US20160057769A1

US20160057769A1 - Uplink enhancements for efficient operation in small cell environments

Info

Publication number: US20160057769A1
Application number: US14/778,985
Authority: US
Inventors: Debdeep CHATTERJEE; Seunghee Han; Jong-Kae Fwu
Original assignee: Intel IP Corp
Current assignee: Intel IP Corp
Priority date: 2013-04-26
Filing date: 2014-03-11
Publication date: 2016-02-25
Also published as: EP2989790B1; CN105103622A; WO2014176245A1; CN105324952A; US20140321360A1; TWI559714B; US10638449B2; CN105052202A; HUE040641T2; HUE037091T2; WO2014175997A1; JP6138340B2; HK1217146A1; EP2989827A1; WO2014176480A1; US9974048B2; TWI552619B; CN105103626B; TW201631957A; US10237846B2

Abstract

In embodiments, apparatuses, methods, and storage media may be described for processes that may be performed in a network with decoupled uplink (UL)-downlink (DL) association. Specifically, if a user equipment (UE) is configured to receive DL transmissions from a macro cell, and transmit UL transmissions to a small cell, hybrid automatic repeat request (HARQ) or power control (PC) may be described.

Description

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to U.S. Provisional Patent Application No. 61/816,662, filed Apr. 26, 2013, entitled “Advanced Wireless Communication Systems and Techniques,” the entire disclosure of which is hereby incorporated by reference in its entirety.

FIELD

Embodiments of the present invention relate generally to the technical field of uplink transmissions in wireless networks.

BACKGROUND

The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in the present disclosure and are not admitted to be prior art by inclusion in this section.
Realization of hyper-dense networks has been identified as a promising direction towards addressing the increased demands from mobile traffic on system capacity and throughput in next-generation wireless systems. In some cases, these hyper-dense networks may involve hotspot deployments in both indoor and outdoor environments and deployment of low-power nodes (LPNs).
In some cases, a hyper-dense network may include both legacy downlink (DL)-uplink (UL) association and decoupled DL-UL association. Specifically, legacy DL-UL association may involve a user equipment (UE) coupled with a cell in the network and be configured to both transmit UL signals to a base station of the cell such as an eNodeB (eNB), and receive DL signals from the eNB. Decoupled DL-UL association may involve a UE that is coupled with two different cells in the network, and the UE may be configured to transmit UL signals to one of the cells while receiving DL signals from another of the cells.
In some cases, decoupled DL-UL association may introduce delay or latency to one or more UL or DL transmissions of the UE.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements. Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings.

FIG. 1 schematically illustrates a high-level example of a network comprising a UE and a base station, in accordance with various embodiments.

FIG. 2 schematically illustrates a high-level example of a network having a UE with decoupled DL-UL association, in accordance with various embodiments.

FIG. 3 depicts an example process for UL signal re-transmission by a UE, in accordance with various embodiments.

FIG. 4 depicts an alternative example of a process for UL signal re-transmission by a UE, in accordance with various embodiments.

FIG. 5 depicts an alternative example of a process for UL signal re-transmission by a UE, in accordance with various embodiments.

FIG. 6 depicts an example of a process for timely delivery of reports from a small cell to a macro cell, in accordance with various embodiments.

FIG. 7 depicts an example power control process, in accordance with various embodiments.

FIG. 8 depicts an alternative example power control process, in accordance with various embodiments.

FIG. 9 schematically illustrates an example system that may be used to practice various embodiments described herein.

DETAILED DESCRIPTION

Apparatuses, methods, and storage media are described herein for identifying one or more procedures for networks with decoupled DL-UL association. Specifically, different processes are discussed related to HARQ and power control (PC). It will be understood that although the different HARQ and PC processes described below are described with respect to decoupled networks, in other embodiments the HARQ and PC processes may be applicable to other networks such as TDD networks with dynamic UL-DL configurations for the purpose of traffic adaptation and interference management.
In the following detailed description, reference is made to the accompanying drawings which form a part hereof wherein like numerals designate like parts throughout, and in which is shown by way of illustration embodiments that may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense.
Various operations may be described as multiple discrete actions or operations in turn, in a manner that is most helpful in understanding the claimed subject matter.
However, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations may not be performed in the order of presentation. Operations described may be performed in a different order than the described embodiment. Various additional operations may be performed and/or described operations may be omitted in additional embodiments.
For the purposes of the present disclosure, the phrases “A and/or B” and “A or B” mean (A), (B), or (A and B). For the purposes of the present disclosure, the phrase “A, B, and/or C” means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).
The description may use the phrases “in an embodiment,” or “in embodiments,” which may each refer to one or more of the same or different embodiments. Furthermore, the terms “comprising,” “including,” “having,” and the like, as used with respect to embodiments of the present disclosure, are synonymous.
FIG. 1 schematically illustrates a wireless communication network 100 (hereinafter “network 100”) in accordance with various embodiments. The network 100 may include a UE 110 coupled with a eNB 105. In some embodiments, the network 100 may be an access network of a third generation partnership project (3GPP) long term evolution (LTE) network such as evolved universal terrestrial radio access network (E-UTRAN). In these embodiments the eNB 105 may be an eNodeB (eNB, also referred to as an evolved NodeB) configured to wirelessly communicate with the UE 110 using a wireless protocol such as the 3GPP LTE wireless protocol.
As shown in FIG. 1, the UE 110 may include a transceiver module 122, which may also be referred to as a multi-mode transceiver chip. The transceiver module 122 may be configured to transmit and receive wireless signals. Specifically, the transceiver module 122 may be coupled with one or more of a plurality of antennas 125 of the UE 110 for communicating wirelessly with other components of the network 100, e.g., eNB 105 or another UE. The antennas 125 may be powered by a power amplifier 130 which may be a component of the transceiver module 122, or coupled with the transceiver module 122 and generally between the transceiver module 122 and the antennas 125 as shown in FIG. 1. In one embodiment, the power amplifier 130 may provide the power for all transmissions on the antennas 125. In other embodiments, there may be multiple power amplifiers on the UE 110. The use of multiple antennas 125 may allow for the UE 110 to use transmit diversity techniques such as spatial orthogonal resource transmit diversity (SORTD), multiple-input multiple-output (MIMO), or full-dimension MIMO (FD-MIMO).
In certain embodiments the transceiver module 122 may include a communication module 120, which may be referred to as a broadband module. Communication module 120 may contain both transmitter circuitry 145 configured to cause the antennas 125 to transmit one or more signals from the UE 110, and receiver circuitry 150 configured to cause the antennas 125 to receive one or more signals at the UE 110. In other embodiments, the communication module 120 may be implemented in separate chips or modules, for example one chip including the receiver circuitry 150 and another chip including the transmitter circuitry 145. In some embodiments the signals may be cellular signals transmitted to or received from a 3GPP eNB such as eNB 105. In some embodiments, the transceiver module 122 may include or be coupled with a re-transmission module 155 configured to facilitate re-transmission of one or more of the wireless signals, as described below.
Similarly to the UE 110, the eNB 105 may include a transceiver module 135. The transceiver module 135 may be further coupled with one or more of a plurality of antennas 140 of the eNB 105 for communicating wirelessly with other components of the network 100, e.g., UE 110. The antennas 140 may be powered by a power amplifier 160 which may be a component of the transceiver module 135, or may be a separate component of the eNB 105 generally positioned between the transceiver module 135 and the antennas 140 as shown in FIG. 1. In one embodiment, the power amplifier 160 may provide the power for all transmissions on the antennas 140. In other embodiments, there may be multiple power amplifiers on the eNB 105. The use of multiple antennas 140 may allow for the eNB 105 to use transmit diversity techniques such as SORTD, MIMO, or FD-MIMO. In certain embodiments the transceiver module 135 may contain both transmitter circuitry 165 configured to cause the antennas 140 to transmit one or more signals from the eNB 105, and receiver circuitry 170 configured to cause the antennas 140 to receive one or more signals at the eNB 105. In other embodiments, the transceiver module 135 may be replaced by transmitter circuitry 165 and receiver circuitry 170 which are separate from one another (not shown). In some embodiments, though not shown, the transceiver module 135 may include a communication module such as communication module 120 that includes the receiver circuitry 170 and the transmitter circuitry 165.
FIG. 2 depicts a high-level example of a network having a UE with decoupled DL-UL association with a macro cell and a small cell, in accordance with various embodiments. Specifically, FIG. 2 depicts a network 200. The network 200 may include a macro cell 205 with a first coverage area. The macro cell 205 may include an eNB 210 which may be similar to eNB 105. The eNB 210 may be configured to transmit and/or receive signals from one or more UEs in the macro cell 205, for example UE 215.
The network 200 may also include one or more small cells such as small cells 220 a, 220 b, and 220 c. The small cells 220 a, 220 b, and 220 c may be grouped in a “cluster” which may be a logical or physical grouping. The small cells 220 a, 220 b, or 220 c may be a piconet, a hotspot deployment, a LPN, or some other type of cell with a smaller coverage area than the macro cell 205. The small cells 220 a, 220 b, and 220 c may each have an eNB such as eNBs 225 a, 225 b, and 225 c, respectively. The eNBs 225 a, 225 b, and 225 c may be configured to transmit and/or receive signals to or from UEs located in a respective small cell 220 a, 220 b, and 220 c. In some embodiments the coverage area of a macro cell may entirely overlap the coverage area of a small cell, for example as shown with small cell 220 c and macro cell 205. In other embodiments the coverage area of a macro cell may only partially overlap the coverage area of a small cell, for example as shown with small cell 220 a and macro cell 205. In some embodiments a small cell may be a remote radio head (RRH) with an identity that is separate from the associated macro cell. For example, the macro cell and the small cells may operate with different physical cell identifiers (PCIs). Therefore, in some embodiments the small cells may not have all the functionalities of an eNB. However, for the sake of consistency small cells will be discussed herein with eNBs, but it will be understood that other configurations of small cells may be usable in different embodiments.
In some embodiments one or more of the small cells may be communicatively coupled to another of the small cells by a backhaul link such as backhaul link 230 shown coupling small cells 220 b and 220 c. Specifically, the eNBs 225 b and 225 c may be communicatively coupled via backhaul link 230. In some embodiments one or more of the small cells may be coupled to the macro cell by a backhaul link such as backhaul link 235 shown coupling small cell 220 a to macro cell 205. Specifically, the eNBs 220 a and 210 may be communicatively coupled via backhaul link 235. The enumerated backhaul links are discussed herein as examples and other links may be present in the network 200. When backhaul links are discussed below, links 230 and 235 will be discussed but it will be understood that the discussion is not exclusive of one or more other backhaul links that may be present in the network 200, such as the backhaul link shown, but not enumerated, between eNBs 220 a and 220 b.
In some embodiments, the network 200 may be configured such that one or more of the small cells 220 a, 220 b, or 220 c use a frequency band that at least partially overlaps the frequency band of the macro cell 205. In embodiments, this may be referred to as co-channel deployment of the macro cell 205 and the small cells 220 a, 220 b, and 220 c, and may be referred to herein as “Scenario 1” or “Sce 1.” In embodiments, Sce 1 may be described as the small cells 220 a, 220 b, or 220 c using the same component carriers (cc's) as the macro cell 205. In some embodiments, one or more of the small cells 220 a, 220 b, or 220 c in a Sce 1 network may be located outdoors. In some embodiments, the small cells 220 a, 220 b, and 220 c may be located relatively close to each other. For example, the small cells 220 a, 220 b, and 220 c of a Sce 1 network may be located relatively closer to one another than small cells described in 3GPP Release 10 (Rel-10) and Release 11 (Rel-11) specifications related to enhanced inter-cell interference (eICIC), further eICIC (FeICIC) or coordinated multi-point (CoMP) transmission scenarios. In a Sce 1 network, the backhaul links 230 and 235 may be “ideal” or “non-ideal.” An ideal backhaul link may be characterized by a very high throughput (for example, up to 10 Gigabits per second) and a very low latency (e.g., less than 2.5 microseconds), while a non-ideal backhaul link may be characterized by typical backhaul technologies such as digital subscriber line technologies (xDSL), microwave, or other backhauls like relaying. Other backhaul links of the network may be non-ideal backhaul links.
In other embodiments, the network 200 may be configured such that one or more of the small cells 220 a, 220 b, or 220 c use a frequency band that does not overlap the frequency band of the macro cell 205, that is the small cells 220 a, 220 b, or 220 c may use different component carriers than the macro cell 205. In some embodiments, the small cells 220 a, 220 b, or 220 c may be located outdoors. In these embodiments, the network 200 may be referred to as a “Scenario 2a” or “Sce 2a” network. In embodiments, the small cells 220 a, 220 b, and 220 c may be located relatively close to one another, such as described above with respect to the Sce 1 network. Additionally, backhaul links 230 and 235 of a Sce 2a network may be either ideal or non-ideal, while other backhaul links of the network may be non-ideal.
In other embodiments, the network 200 may be configured similarly to the Sce 2a network described above, however one or more of the small cells 220 a, 220 b, or 220 c may be located indoors. In this embodiment, the network 200 may be referred to as a Sce 2b network. In a Sce 2b network, one or more of the small cells 220 a, 220 b, or 220 c may use different frequencies or component carriers than the macro cell 205. Additionally, backhaul links 230 and 235 may be idea or non-ideal, while other backhaul links are non-ideal. In a Sce 2b network, the small cells 220 a, 220 b, or 220 c may be located relatively close to one another as described with respect to the Sce 1 and Sce 2a networks. However, in some embodiments the small cells 220 a, 220 b, or 220 c may be relatively sparse such as the indoor hotspot scenario discussed with respect to the 3GPP Rel-10 specifications.
In some embodiments, a Sce 1 network may be different from, for example, a CoMP such as the CoMP networks described in the 3GPP Rel-11 specifications. In some embodiments, it may be desirable for the Sce 1 network to exhibit improved non-ideal backhaul connectivity over backhaul links 230 and 235. Additionally, as mentioned above, a Sce 1 network may have a higher density of small cells 220 a, 220 b, and 220 c in a cluster than the density of a CoMP network.
In some embodiments Sce 2a and Sce 2b networks may be different than a network with carrier aggregation (CA) such as those proposed in the 3GPP Rel-11 specifications. Specifically, Sce 2a and Sce 2b networks may allow for non-ideal backhaul connectivity between different cells, such as over backhaul links 230 or 235. CA is discussed in greater detail below with respect to Sce 2a and Sce 2b networks.
A UE 215 of a network 200 with decoupled DL-UL association may be in both a coverage area of a macro cell 205 and a coverage area of a small cell 220 c, as shown in FIG. 2. In some embodiments, it may benefit the UE 215 to receive DL signals from the eNB 210 of the macro cell 205, while transmitting UL signals to the eNB 225 c of the small cell 220 c. For example, if the UE 215 is near the cell edge of the small cell 220 c, the DL signal from the eNB 210 of the macro cell 205 may be stronger than a DL signal from the eNB 225 c of the small cell 220 c. However, the UL pathloss of a UL transmission from the UE 215 to the eNB 225 c of the small cell 220 c may be smaller than the UL pathloss of a UL transmission from the UE 215 to the eNB 210 of the macro cell 205. The difference in pathloss may be, for example, because the UE 215 may only have a limited transmission power. The benefits of the decoupled DL-UL associations may be even larger for UEs that may not benefit from cell range expansion (CRE) and eICIC or FeICIC mechanisms as described in 3GPP Rel-10 and Rel-11 specifications due to heavy cell reference signal (CRS) interference from the macro cell 205 in the absence of efficient CRS cancellation receivers.
In embodiments, a network 200 with decoupled DL-UL association with non-ideal backhaul may experience one or more difficulties. Specifically, the network 200 may experience one or more difficulties with regards to timely transmission of Physical Hybrid Automatic Repeat Request Indication Channel (PHICH) transmissions from the eNB 210 of the macro cell 205 corresponding to Physical Uplink Shared Channel (PUSCH) transmissions from the UE 215 to the eNB 225 c of the small cell 220 c. Secondly, the network 200 may experience one or more difficulties with regards to timely delivery of DL Hybrid Automatic Repeat Request (HARQ) Acknowledgement (ACK) signals, herein referred to as HARQ-ACK signals, or HARQ non-Acknowledgement (NACK) signals, herein referred to as HARQ-NACK signals, and channel state information (CSI) reports from the small cell 220 c to the macro cell 205. Thirdly, the network 200 may experience one or more difficulties with regards to power control for UEs with decoupled DL-UL association. Each of the above described difficulties, and potential resolutions to that difficulties, will be described in greater detail below.
In the discussion below, transmissions will be discussed between two cells, for example the macro cell 205 and the small cell 225 c, or between the UE 215 and one of the cells. The transmissions may be discussed with respect to wireless transmissions to/from the UE 215, or backhaul transmissions between two cells. However, when cells are referred to, it will be understood that the transmissions may be between the respective eNBs of the cells.
PHICH Transmissions Corresponding to PUSCH Transmissions
In a network such as network 200, it may be desirable to control the timing of DL PHICH transmissions and UL PUSCH transmissions, because the PHICH and PUSCH transmissions may be related and useful for one or more processes such as HARQ processes. Specifically, the UE may transmit a first UL signal to an eNB, for example in a UL PUSCH transmission. In some cases, the UE may then receive an indication in a DL PHICH transmission that the UE should re-transmit the signal. The indication may be based, for example, on interference in the signal, missing data, or some other reason. In response to receiving the indication, the UE may re-transmit the signal in a UL PUSCH transmission. A brief discussion of legacy HARQ processes indicating a timing relationship between DL PHICH transmissions and UL PUSCH transmissions is given below. In some embodiments, the timing relationship may be based on a maximum allowed HARQ-ACK re-transmission delay. That is, the longest time allowed between the transmission of an original signal and a re-transmission of that signal based on a DL PHICH indication. In some embodiments, the re-transmission delay may be 8 ms.
Specifically, in frequency division duplexing (FDD) systems, a legacy UE may expect to receive HARQ-ACK feedback from an eNB in subframe i of a radio frame that has one or more subframes. Specifically, in some embodiments the radio frame may have 10 subframes. The HARQ-ACK feedback in subframe i may correspond to a UL PUSCH transmission in subframe i-4 of the radio frame (or a previous radio frame).
In a time division duplexing (TDD) system, assuming that the UE is configured with a single serving cell or multiple serving cells with the same UL/DL TDD subframe configuration, the legacy behavior of the UE for UL HARQ-ACK may be described with reference to 3GPP Technical Specification (TS) 36.213 v11.2.0 (February, 2013).
Specifically, for Frame Structure type 2 UL/DL configuration 1-6, a DL HARQ-ACK signal received on the PHICH assigned to a UE in subframe i may be associated with the UL PUSCH transmission in the subframe i-k as indicated in Table 1, below. Table 1 may correspond to Table 8.3-1 of 3GPP TS 36.213 v11.2.0.

TABLE 1

TDD UL/DL	subframe number i

Configuration	0	1	2	3	4	5	6	7	8	9

0	7	4				7	4
1		4			6		4			6
2				6					6
3	6								6	6
4									6	6
5									6
6	6	4				7	4			6

For Frame Structure type 2 UL/DL configuration 0, a HARQ-ACK signal may be received by the legacy UE in a DL PHICH transmission in a resource corresponding to I_PHICH=0, for example as described in Section 9.1.2 of 3GPP TS 36.213 v11.2.0, assigned to the UE in subframe i. The resource may be associated with the corresponding UL PUSCH transmission in subframe i-k as indicated above in Table 1. For Frame Structure type 2 UL/DL configuration 0, a HARQ-ACK received in a DL PHICH transmission in the resource corresponding to I_PHICH=1 assigned to a UE in subframe i may be associated with an UL PUSCH transmission in the subframe i-6.
Additionally, for FDD and normal HARQ operation, a legacy UE may detect, on a given serving cell, a DL Physical Downlink Control Channel (PDCCH) or enhanced PDCCH (ePDCCH) transmission with downlink control information (DCI) format 0/4, and/or a DL PHICH transmission in subframe n intended for the UE. In response, the UE may adjust the corresponding UL PUSCH transmission in subframe n+4 according to the detected DL PDCCH, ePDCCH, and/or PHICH information.
For TDD, if a UE is configured with a single serving cell, or if the UE is configured with more than one serving cell and the TDD UL/DL configuration of all of the configured serving cells is the same, the UE may adjust the timing of a UL PUSCH transmission based on reception of a DL PDCCH, ePDCCH, or PHICH transmission. Specifically, for TDD UL/DL configurations 1-6 and normal HARQ operation, the UE 215 may, upon detection of a DL PDCCH or ePDCCH transmission with a UL DCI format, and/or detection of a DL PHICH transmission in subframe n intended for the UE 215, adjust the corresponding UL PUSCH transmission in subframe n+k, as indicated in Table 2 below. This timing adjustment may be based at least in part on the PDCCH, ePDCCH, and/or PHICH information.

TABLE 2

TDD UL/DL	subframe number n

Configuration	0	1	2	3	4	5	6	7	8	9

0	4	6				4	6
1		6			4		6			4
2				4					4
3	4								4	4
4									4	4
5									4
6	7	7				7	7			5

For TDD UL/DL configuration 0 and normal HARQ operation, the UE may likewise adjust the timing of a UL PUSCH transmission. Specifically, the UE may detect a DL PDCCH or ePDCCH transmission with a UL DCI format and/or a DL PHICH transmission in subframe n intended for the UE. In response, the UE may adjust the corresponding UL PUSCH transmission in subframe n+k if the most significant bit (MSB) of the UL index in the PDCCH or ePDCCH transmission with UL DCI format is set to 1, or if the DL PHICH transmission is received in subframe n=0 or 5 in the resource corresponding to I_PHICH=0, for example as described in Section 9.1.2 of TS 36.213 v11.2.0. In this mode of operation, k may be given a value as shown above in Table 2.
If, for TDD UL/DL configuration 0 and normal HARQ operation, the least significant bit (LSB) of the UL index in the DCI format 0/4 is set to 1 in subframe n, or a DL PHICH transmission is received in subframe n=0 or 5 in the resource corresponding to I_PHICH=1, for example as described in Section 9.1.2 of TS 36.213 v11.2.0, or a DL PHICH is received in subframe n=1 or 6, the UE may adjust the corresponding UL PUSCH transmission in subframe n+7.
If, for TDD UL/DL configuration 0, both the MSB and LSB of the UL index in the received PDCCH or ePDCCH transmission with a UL DCI format are set in subframe n, then the UE 215 may adjust the corresponding UL PUSCH transmission in both subframe n+k and n+7, with k described in Table 2 above.
As can be seen above, the timing of a DL PHICH, PDCCH, or ePDCCH transmission relative to the timing of a corresponding UL PUSCH transmission may be strictly controlled. However, if a UE 215 is in a network 200 with decoupled DL-UL association, then the DL PHICH, PDCCH, or ePDCCH transmissions may be received by the UE 215 from the macro cell 205 while the corresponding UL PUSCH transmission may be transmitted by the UE 215 to the small cell 220 c. The decoupled DL-UL association may introduce delays because the macro cell 205 and the small cell 220 c may have to coordinate with one another over backhaul links such as backhaul links 230 and 235. Specifically, if timing of a UL PUSCH transmission received by the small cell 220 c is related to timing of a DL PHICH transmission of the macro cell 205, the cells 220 c and 205 may be required to communicate with one another over the backhaul links, which may delay the HARQ process. Four alternative solutions to coordinating the timing of UL PUSCH transmissions and DL PHICH, PDCCH, or ePDCCH transmissions are described below.
As a first alternative solution, the HARQ-ACK retransmission delay may be extended from 8 ms to 16 ms for FDD transmissions. Additional UL grants may be transmitted from the macro cell 205 to the UE 215 in a PDCCH or ePDCCH transmission. A UL grant may indicate to the UE 215 when the UE 215 is assigned UL resources for UL transmissions, for example UL PUSCH transmissions. In some embodiments, the UL grant may include an indication that the UE 215 is to re-transmit the previous UL transmission to the small cell 220 c. Therefore, the UL grant may take the place of a DL PHICH transmission because the UL grant may be used to trigger the UL re-transmission instead of the DL PHICH transmission. In some embodiments the DL PHICH transmission may not even occur, and the network 200 may be considered PHICH-less.
In some embodiments, the PUSCH decoding results, that is the result of the eNB 225 c decoding the original PUSCH transmission, may need to be forwarded to eNB 210, for example over backhaul links 230 and 235. In some embodiments the results may need to be forwarded within a time-window that allows for sufficient time-budget for the transmission of the UL grants from the macro cell 205. For example, if the network 200 is an FDD network, with the extension of the HARQ-ACK retransmission delay to 16 ms, the macro cell 205 may need to transmit the UL grant indicating retransmission within 12 subframes of the original PUSCH UL transmission to maintain a similar timing relationship as in legacy UE operation of (n+4)-th subframe PUSCH retransmission in FDD deployments if the UL grant or DL PHICH indicating retransmission is received on the n-th subframe. Additionally, in some embodiments the UE 215 may be configured to receive a signal or indication, for example from higher layers, regarding whether to use a HARQ-ACK retransmission delay of 8 ms and a HARQ-ACK retransmission delay of 16 ms. Additionally, if a higher HARQ-ACK retransmission delay is used, the maximum number of HARQ processes allowed in the network 200 may be higher than 8 concurrent HARQ processes, which is the maximum number of HARQ processes allowed in the currently specified 3GPP LTE specifications.
As a second alternative solution, PUSCH scheduling information may be transmitted to the UE 215 in a DL ePDCCH transmission from the small cell 220 c. In this embodiment, the operation of the network 200 may be PHICH-less. That is, the eNBs may not trigger re-transmission of a UL PUSCH transmission using a DL PHICH transmission as described above. In this embodiment, UL grants indicating retransmission may be transmitted to the UE 215 from the small cell 220 c in DL ePDCCH transmissions from the small cell 220 c. In this embodiment, the HARQ-ACK information may not need to be extended because the timing of the PUSCH UL signals targeted to the small cell 220 c may be controlled by the small cell 220 c.
In some embodiments it may be possible for the small cell 220 c to transmit UL grants using dynamic point selection (DPS) ePDCCH scheduling as described in the 3GPP Rel-11 specifications. In this embodiment two ePDCCH sets may be configured for the UE 215. The ePDCCH sets may respectively correspond to the transmissions from the macro cell 205 and the small cell 220 c, respectively. The two ePDCCH sets may be scheduled by configuring difference virtual cell identifiers (VCIDs) corresponding to the macro cell 205 and the small cell 220 c for the respective ePDCCH sets.
FIG. 3 depicts an example process that briefly summarizes the two alternative solutions described above. Initially, UE 215 may receive at 300 a transmission from a macro cell 205. For example, the UE 215 may receive a DL transmission such as a PDCCH or ePDCCH transmission from macro cell 205. The UE 215 may then transmit a DL transmission at 305 to a small cell 220 c. Specifically, the UE 215 may transmit a UL PUSCH transmission to small cell 220 c. The UE 215 may then receive at 310 a UL grant. For example, as described above, the UL grant may be received in a DL PDCCH or ePDCCH transmission from the macro cell 205 or the small cell 220 c. Finally, the UE 215 may re-transmit at 315 the UL PUSCH transmission to the small cell 220 c based on the received UL grant.
As a third alternative solution, and with reference to FIG. 4, UE 215 may receive at 400 a transmission from a macro cell 205. For example, the UE 215 may receive a DL transmission such as a DL PDCCH or ePDCCH transmission from macro cell 205. The UE 215 may then transmit a UL transmission at 405 to a small cell 220 c. Specifically, the UE 215 may transmit a UL PUSCH transmission to small cell 220 c. The UE 215 may then receive at 410 PUSCH scheduling information from macro cell 205, for example in a DL PDCCH or ePDCCH transmission. The PUSCH scheduling information may be controlled by the macro cell 205 even though the UL PUSCH transmission may be targeted to the small cell 220. In this embodiment, the PUSCH scheduling information may include a new data indicator which indicates whether to transmit new data or whether to re-transmit a previously transmitted PUSCH transmission. If the new data indicator indicates to not transmit new data, for example the indicator has a value of “0,” then the scheduled PUSCH transmission may be used to re-transmit a previous PUSCH UL transmission at 415. For example, the previous UL PUSCH transmission may be stored in a buffer of the UE 215, and the UE 215 may not flush its buffer before re-transmitting the previous UL PUSCH transmission. In this embodiment if a DL PHICH transmission is received, the UE 215 may not act according to the received DL PHICH transmission.
A fourth alternative process may be discussed with reference to FIG. 5. UE 215 may receive at 500 a transmission from a macro cell 205. For example, the UE 215 may receive a DL transmission such as a DL PDCCH or ePDCCH transmission from macro cell 205. The UE 215 may then transmit a transmission at 505 to a small cell 220 c. Specifically, the UE 215 may transmit a UL PUSCH transmission to small cell 220 c. A DL PHICH transmission corresponding to the UL PUSCH transmission may be received by the UE 215 at 510 from the small cell 220 c rather than the macro cell 205. In some embodiments, the macro cell 205 and small cell 220 c may have different PCIs In embodiments, the DL PHICH transmission may be based on the PCI of the cell transmitting the DL PHICH transmission. Therefore, in this embodiment the UE 215 may attempt to detect the DL PHICH transmission based on the PCI of the small cell 220 c at 515. Based on the detected PCI parameters, the DL PHICH transmission may be identified and decoded, and the UE 215 may re-transmit the previous UL PUSCH transmission.
In some embodiments, the UE 215 may be configured with the PCI to be used for detecting and decoding a DL PHICH transmission by way of radio resource control (RRC) signaling received in a DL physical downlink shared channel (PDSCH) transmission. The RRC signaling may be UE-specific and received in a system information block (SIB) message of a DL physical downlink shared channel (PDSCH) transmission. The RRC signaling may further contain an indicator of the PCI to use, the number of OFDM symbols for a DL PDCCH transmission, a starting symbol for a DL PDSCH transmission, the duration of a DL PHICH transmission, and/or other configuration parameters of the DL PHICH transmission that are currently associated with the PBCH transmissions in legacy systems for a UE 215 to receive a DL PHICH transmission from the small cell 220 c. In some embodiments the Ng value of the PHICH configuration may have been received in a DL physical broadcast channel (PBCH) transmission from an eNB of the network 205. As a default operation, in case a UE 215 is not configured by the UE-specific RRC signaling for decoding the received DL PHICH transmission, the UE 215 may use the configuration for a DL serving cell such as the macro cell 205 which has a system information block-2 (SIB-2) linkage.
In the embodiments described above, one or more of the elements of the processes depicted in FIG. 3, 4, or 5 may be performed in a different order. For example, in some embodiments the UE 215 may be pre-configured with decoupled DL-UL association. Therefore, the initial transmission from the macro cell at 300, 400, or 500 may not occur, or may occur after the small cell transmission at 305, 405, or 505.
DL HARQ-ACK and CSI Reports
In some embodiments macro cell 205 may transmit data to the UE 215, for example using a DL PDSCH transmission. In response, the UE 215 may provide HARQ feedback such as a HARQ-ACK or HARQ-NACK message in a UL physical uplink control channel (PUCCH) transmission. Upon receiving the HARQ feedback message, the macro cell 205 may re-transmit the data transmission in a subsequent DL PDSCH transmission. This process may be referred to as DL HARQ. In some embodiments, DL HARQ may be asynchronous. That is, the network 200 may include a plurality of HARQ processes and any of the HARQ processes may be used in DL HARQ. As a result, a strict DL HARQ round-trip time may not be mandatory. However, in some embodiments the UE 215 may transmit the HARQ feedback message to the small cell 220 c. In order for the macro cell 205 to re-transmit the data transmission, the small cell 220 c may need to forward to HARQ feedback message to the macro cell 205, for example over backhaul links 230 and 235. The forwarding of the HARQ feedback message may introduce undesirable latency that may affect traffic with strict QoS or latency requirements.
Additionally, in some embodiments the UE 215 may provide channel state information (CSI) feedback to the small cell 220 c in a UL PUCCH transmission. The CSI feedback may be related to the quality of one or more communication channels of the network 200, and may be used by the small cell 220 c or macro cell 205 to adjust one or more parameters of the UL or DL transmissions respectively. In some embodiments, it may be desirable for the small cell 220 c to supply the CSI feedback to the macro cell 205 so that the macro cell 205 may adjust a parameter of the DL transmissions if a particular signal or frequency is experiencing QoS degradation due to interference or some other reason. In some embodiments, if transmission of the CSI feedback from the small cell 220 c to the macro cell 205 is delayed, the quality of the DL transmissions may be degraded because the macro cell 205 may not be able to adjust the parameter(s) of the DL transmissions.
In some embodiments, the UL PUCCH transmissions may be formatted according to a PUCCH format as described, for example, in 3GPP TS 36.213 v11.2.0 (February, 2013), §10.1.1. In some embodiments, one or more of the above described difficulties may be reduced or minimized if UL PUCCH transmissions carrying delay-sensitive HARQ-ACK feedback are targeted directly to the macro cell 205. For example, UL PUCCH transmissions that are formatted according to PUCCH formats 1a, 1b, or 3 may be delay-sensitive. Therefore, UL PUCCH transmissions with those PUCCH formats may be targeted directly to the macro cell 205. These UL PUCCH transmissions may be targeted to the macro cell 205 through semi-static configuration of virtual cell identifiers (VCIDs) that are both format-specific and UE-specific. These VCIDs may be used for the generation of the PUCCH transmission base sequences.
Resource allocation for UL PUCCH format 1a or 1b transmissions may be signaled using a combination of semi-static RRC signaling of the PUCCH starting offset and other dynamic parameters described below via a DL PDCCH or ePDCCH transmission from the macro cell 205 or via a DL ePDCCH transmission from the small cell 220 c. Specifically, the semi-static RRC signaling may include a PUCCH starting offset for PUCCH formats 1a or 1b. Specifically, UE-specific signaling of a PUCCH format 1a or 1b starting offset, N⁽¹⁾ _PUCCH _— _UEfor PDCCH and N⁽¹⁾ _{PUCCH. j}for ePDCCH set j, respectively, may be configured via higher layers based on coordination between the macro cell 205 and the small cell 220 c. In embodiments, the configuration of the PUCCH format 1a or 1b starting offset may be considered to be semi-static because it is signaled via the RRC and may not change with a high frequency (i.e. change on a frequency of approximately 600 milliseconds). Therefore, those parameters may be considered “semi-static.” Given the semi-static nature of this configuration, necessary PUCCH resource coordination between the macro cell 205 and the small cell 220 c to determine the UE-specific PUCCH format 1a or 1b starting position may be feasible even with non-zero backhaul latency. In some embodiments, the final dynamic resource allocation information may be determined by using the semi-statically configured UE-specific PUCCH 1a/1b starting offset, a lowest control channel element (CCE), n_CCEfor the DL PDCCH or ePDDCH transmission from the macro cell 205 or small cell 220 c, an antenna port (AP) configuration of the UE 215, or ACK-NACK resource offset (ARO) configuration. In some embodiments the AP configuration or ARO configuration information may be most applicable to ePDCCH-based dynamic resource allocation for PUCCH format 1a or 1b.
For PUCCH format 3, the UE-specific resource allocation may likewise be semi-static. Therefore, in embodiments the macro cell 205 and small cell 220 c may synchronize the resource allocation information over the backhaul even with non-zero delay.
In some embodiments, the network 200 may have a maximum number of DL HARQ processes that can be maintained between the network 200 and the UE 215. For example, in FDD networks, the network 200 may allow a maximum of 8 DL HARQ processes between the network 200 and the UE 215. In TDD networks, the network 200 may allow a maximum of between 4 and 15 DL HARQ processes dependent on a TDD UL/DL configuration of the TDD transmission. The TDD UL/DL configuration may be as described, for example, in Table 7-1 of 3GPP TS 36.213 v11.2.0 (February, 2013). In some embodiments, the maximum number of DL HARQ processes may be increased to provide more flexibility in scheduling HARQ-ACK feedback. For example, some HARQ-ACK feedback may still be routed through the small cell 220 c via UL PUCCH transmissions using PUCCH formats 2a or 2b. This HARQ-ACK feedback may be related to DL PDSCH, PDCCH, or ePDCCH transmissions that are not highly latency sensitive. Although PUCCH formats 2a and 2 b are used herein as an example, in some embodiments the specific PUCCH format may be based on the use of a normal cyclic prefix (CP) and in other embodiments the specific PUCCH format may be different.
In some embodiments, the delay-sensitive HARQ-ACK feedback that is targeted to the macro cell 205 may also be accompanied by a scheduling request (SR) that may be needed by the small cell 220 c. In some embodiments, the SR may need to be forwarded by the macro cell 205 to the small cell 220 c, for example over backhaul links 230 and 235. In some embodiments, UL grants for UEs 215 with decoupled DL-UL association may be transmitted by the small cell 220 c using one or more DL ePDCCH transmissions. Buffer status reports (BSRs) and SRs in UL PUCCH transmissions using PUCCH format 1 from a UE 215 with decoupled DL-UL association may be received at the small cell 220 c. Reception of these UL PUCCH transmissions may facilitate maximal decoupling of DL and UL scheduling from the macro cell 205 and the small cell 220 c, respectively.
FIG. 6 depicts a high level example of a process for DL HARQ according to the embodiments described above. Initially, the UE 215 may identify the transmission format of the UL PUCCH transmission at 600. Based on the format, a format-specific and UE-specific VCID may be generated at 605. The VCID may be used as the basis for generating a PUCCH base sequence at 610. One or more dynamic transmission parameters may then be identified at 615 and a UL PUCCH transmission may be generated at 620 that targets the macro cell 205.
UL PC
In some embodiments a UE 215 with decoupled UL-DL association may be subjected to inefficiencies with regards to UL PC. Specifically, with regards to Sce 1 networks, a decoupled DL-UL association may require careful selection of which pathloss reference to use for open loop (OL) PC. For example, a PC process that relies on the DL association point, that is eNB 210, as a pathloss reference may not be ideal for a UL PC process because the DL pathloss may be different than the UE pathloss. Therefore, careful selection of the pathloss reference for the UL PC may be desirable.
Additionally, a decoupled DL-UL association may generate inefficiencies regarding how a closed loop (CL) PC mechanism may operate in a network 200 with a non-ideal backhaul between a macro cell 205 and a small cell 220 c. Specifically, CL PC may not be configured to compensate for a UE 215 with decoupled DL-UL association when the UE 215 uses a different pathloss reference for OL PC calculations than CL PC calculations because it may be very difficult for the macro cell 205 and small cell 220 c to share a common PC process for a particular UE 215 over non-ideal backhaul links with a delay as low as 10-30 ms. Similar challenges may be present for UL PC for Sce 2a and Sce 2b networks.
In the description below, different PC processes may be most relevant to different channels. Additionally, different PC processes may be most relevant to Sce 1, Sce 2a, or Sce 2b networks. Therefore, the different channels and networks are addressed individually below. However, the different processes described below are merely examples of different embodiments, and certain channels may find efficiencies from using processes described for another channel in other embodiments.
PUSCH-Sce 1
For PUSCH transmissions, the CL PC process may be maintained at the small cell 220 c, and transmit power control (TPC) commands may be sent by the small cell 220 c along with UL grant information using ePDCCH DL transmissions. The UL grant information may be similar to the UL grant information described above. The transmission of the TPC commands and the UL grant information may assist the UE 215 in CL PC processes for low-mobility UEs. A low-mobility UE may be a UE 215 that is moving with a relatively low frequency or velocity.
In some embodiments, if the UE 215 uses the DL association point as its pathloss reference, an adjustment to the UL OL PC may be desirable. Specifically, to adjust for the use of a non-ideal DL pathloss reference in a UL PC process, an additional accumulative or non-cumulative TPC parameter may be used by the small cell 220 c to compensate for the non-ideal DL pathloss reference. Alternatively, the existing TPC field bit-width may be increased by one or more bits to support a larger range of TPC commands that may be used to compensate for the non-ideal DL pathloss reference. In other embodiments a different parameter or value may be used to compensate for the non-ideal DL pathloss reference.
PUCCH—Sce 1
Two options may be available for the selection of a pathloss reference for PUCCH PC in Sce 1 networks. Specifically, as a first option (referred to herein as Option 1a), a UE 215 may use the macro cell 205 (i.e. the DL association point) as its pathloss reference. As a second option (referred to herein as Option 1b), a UE 215 may be signaled via higher layers or Layer 1 signaling as to whether to use the macro cell 205 or the small cell 220 c (i.e. the UL association point) as its pathloss reference. As used herein, the use of the macro cell 205 as a pathloss reference may be referred to as a DL pathloss reference, while the use of the small cell 220 c as a pathloss reference may be referred to as a UL pathloss reference.
OL PC may be performed using one or more parameters such as P_O _— _PUCCH, P_O _— _NOMINAL _— _PUCCH, or P_O _— _UE _— _PUCCHas described, for example, in 3GPP Technical Specification (TS) 36.213 v11.2.0 (February, 2013), §5.1.2. In some embodiments, P_O _— _PUCCHmay be the sum of P_O _— _NOMINAL _— _PUCCH, which may be a cell-specific parameter indicated via RRC signaling, and P_O _— _UE _— _PUCCH, which may be a UE-specific parameter indicated via RRC signaling.
For Option 1b, the UE 215 may be configured with two values for the OL PC parameters such as P_O _— _PUCCH, one each corresponding to the UL pathloss reference and DL pathloss reference, respectively. For the case of independent configuration of the two values of P_O _— _PUCCH, a common value of P_O _— _NOMINAL _— _PUCCHmay be configured with two independent configurations of P_O _— _UE _— _PUCCHprovided by higher layers, one each corresponding to the UL pathloss reference and DL pathloss reference, respectively. For this embodiment, each configuration of P_O _— _UE _— _PUCCHmay be associated with a different CL PC process (as described in further detail below with regards to Option 2a) because reconfiguration of the P_O _— _UE _— _PUCCHvalue may result in a resetting of the PUCCH power control adjustment state (i.e. the CL PC process).
Two options may be available for CL PC processes for PUCCH. Specifically, as a first option (referred to herein as Option 2a), two independent CL PC processes may be maintained for each UE in the network. The processes may be maintained at the UE side as well as the network side. One of the processes may be maintained at the macro cell 205 and the other may be maintained at the small cell 220 c. In embodiments, the different PUCCH processes may be maintained and performed substantially in parallel with or concurrently with one another. As a second option (referred to herein as Option 2b), only one CL PC process for PUCCH may be maintained.
For Option 2a, for each CC, one or more CL PC processes for PUSCH may be maintained at the small cell 220 c, and two independent concurrent PC processes may be maintained for PUCCH. Specifically, one CL PC process may be maintained for PUCCH UL transmissions carrying delay-sensitive DL HARQ-ACK information targeted for the macro cell 205 (for example, UL PUCCH transmissions with PUCCH formats 1a, 1b, and 3). Another CL PC process may be maintained for PUCCH UL transmissions carrying CSI (for example, PUCCH UL transmissions with PUCCH formats 1, 2, 2a, or 2b) that may be received by the small cell 220 c.
In some embodiments, certain OL PC parameters such as P_O _— _PUCCHmay need to be communicated between the macro cell 205 and the small cell over backhaul links 230 and 235. In other embodiments the UE 215 may be configured with independent sets of OL PC parameters, for example as proposed under Option 1b, above.
If Option 2a is used in conjunction with Option 1b (i.e. with the use of multiple pathloss references), then a TPC command for PUCCH transmissions that may be received at the UE 215 in a DL PDCCH or DL ePDCCH transmission, may need to be associated with one of the CL PC processes. The CL PC process to which the TPC command should be applied may be implicitly indicated by association of each PUCCH CL PC process to the respective pathloss reference choice. Specifically, the UE may maintain two CL PC processes and apply the TPC parameter that is dynamically signaled (via PDCCH or ePDCCH) to the corresponding CL PC process depending on which pathloss reference was signaled to the UE for use via RRC signaling per Option 1b.
If Option 2a is used in conjunction with Option 1a (i.e., UE 215 uses the DL association point as its pathloss reference), then the use of an appropriate CL PC process may be defined in a PUCCH format-specific manner. For example, a first CL PC process may be maintained at the macro cell 205 for UL PUCCH transmissions with PUCCH formats 1a, 1b, or 3. A second CL PC process may be maintained at the small cell 220 c for UL PUCCH transmissions with PUCCH formats 1, 2, 2a, or 2b. Additional or alternative processes may be used in other embodiments, or the processes may be split between different PUCCH formats. Additionally or alternatively, explicit dynamic signaling may be used to indicate the application of the particular CL PC process. For instance, one new bit in a downlink control information (DCI) signal received in a DL PDCCH or ePDDCH transmission may be used to indicate which CL PC process the TPC command should be applied to.
A general process for UL PC for a UE 215 that incorporates one or more of the embodiments above related to Option 2a may be described with respect to FIG. 7. Initially, the UE 215 may identify the CL PC process for PUSCH at 700, as described above. Next, the UE 215 may identify a CL PC process for a first set of UL PUCCH transmissions with PUCCH formats such as 1a, 1b, or 3 at 705. Next, the UE 215 may identify a CL PC process for a second set of UL PUCCH transmissions with PUCCH formats such as 1, 2, 2a, or 2 b at 710. Finally, the UE 215 may optionally identify the pathloss reference to use for the PC processes at 715. The pathloss reference may be the UL pathloss reference or the DL pathloss reference, and may be signaled via higher layer signaling, Layer 1 signaling, or some other type of signal or indicator.
If Option 2b is used in conjunction with Option 1a then UE 215 may use the DL association point as its pathloss reference. In some embodiments the CL PC process for PUCCH may be maintained at the macro cell 205. For UL PUCCH transmissions carrying delay-sensitive HARQ-ACK information (e.g. UL PUCCH transmissions formatted according to PUCCH formats 1a, 1b, and 3) targeted to the macro cell 205, assuming the macro cell 205 is maintaining the CL PC process, normal PC for PUCCH may be applied as specified in existing Rel-10 and Rel-11 3GPP specifications.
For other PUCCH transmissions targeted to the small cell 220 c, for example UL PUCCH transmissions formatted according to PUCCH formats 1, 2, 2a, 2 b or some other format, the PUCCH UL transmission may be adjusted to account for the use of the DL pathloss reference in the UL transmission targeting the small cell 220 c (assuming the macro cell 205 is maintaining the CL PC process). In one embodiment, the TPC value carried as part of the DCI may be applied as a non-cumulative TPC command. In this embodiment, the bit-width for the TPC field for PUCCH may be increased or altered to accommodate a larger range of TPC commands. Alternatively, a new field may be added to one or more DCI formats such as DCI formats 1A, 1B, 1D, 1, 2A, 2, 2B, 2C, or 2D, which may be carried by a DL ePDCCH transmission received from the small cell 220 c. In this embodiment, the new field in the received DCI may be applied as an additional non-cumulative parameter instead of the TPC field discussed above.
If Option 2b is used in conjunction with Option 1a then UE 215 may use the DL association point as its pathloss reference. In some embodiments, the CL PC process for PUCCH may be maintained at the small cell 220 c. For UL PUCCH transmissions carrying delay-sensitive HARQ-ACK information (e.g. UL PUCCH transmissions formatted according to PUCCH formats 1a, 1b, and 3) targeted to the small cell 220 c, normal PC for PUCCH may be applied as specified in existing Rel-10 and Rel-11 3GPP specifications (assuming the small cell 220 c is maintaining the CL PC process). However, in some embodiments the bit-width of the existing TPC field may be extended to compensate for the effect of UE 215 using a wrong pathloss reference, i.e., pathloss reference to the macro cell as per Option 1a.
For other PUCCH transmissions targeted to the macro cell 205, for example UL PUCCH transmissions formatted according to PUCCH formats 1, 2, 2a, 2 b or some other format, the UL PUCCH transmission may be adjusted to account for the use of the DL pathloss reference in the UL transmission targeting the macro cell 205 (assuming the CL PC process is maintained at the small cell 220 c). In one embodiment, the TPC value carried as part of the DCI may be applied as a non-cumulative TPC command. Alternatively, a new field may be added to one or more DCI formats such as DCI formats 1A, 1B, 1D, 1, 2A, 2, 2B, 2C, 2D, 3, or 3A which may be carried by a DL ePDCCH transmission received from the macro cell 205. In this embodiment, the new field in the received DCI may be applied instead of the TPC field discussed above.
If Option 1b is used in conjunction with Option 2b, then the pathloss reference may be signaled via higher layers as described previously. In some embodiments, the CL PC process for PUCCH may be maintained at the macro cell 205. For UL PUCCH transmissions carrying delay-sensitive HARQ-ACK information (e.g. UL PUCCH transmissions formatted according to PUCCH formats 1a, 1b, and 3) targeted to the macro cell 205, assuming the macro cell 205 is maintaining the CL PC process, normal PC for PUCCH may be applied as specified in existing Rel-10 and Rel-11 3GPP specifications.
For other PUCCH transmissions targeted to the small cell 220 c, the TPC field for PUCCH in the received DCI may be re-interpreted as a non-cumulative TPC command, in which case the bit-width for the TPC field for PUCCH may be further increased to accommodate additional TPC commands. Alternatively, a new field may be added to the DCI formats 1A, 1B, 1D, 1, 2A, 2, 2B, 2C, or 2D (which may correspond to DCI transmissions carried by an ePDCCH DL transmission from the small cell 220 c) as an additional non-cumulative TPC command for PUCCH that is applied instead of the TPC field currently specified in existing 3GPP Rel-10 and Rel-11 specifications.
If Option 1b is used in conjunction with Option 2b, then the pathloss reference may be signaled via higher layers as described previously. In some embodiments, the CL PC process for PUCCH may be maintained at the small cell 220 c. For UL PUCCH transmissions carrying delay-sensitive HARQ-ACK information (e.g. UL PUCCH transmissions with PUCCH formats 1a, 1b, or 3) targeted to the macro cell 205, the TPC field for a UL PUCCH transmission in a received DCI command may be re-interpreted as a non-cumulative TPC command. In this embodiment, the bit-width for the TPC field for PUCCH may be increased. Alternatively, a new field may be added to the DCI formats 1A, 1B, 1D, 1, 2A, 2, 2B, 2C, 2D, 3, or 3A (which may be carried by DL PDCCH or ePDCCH transmissions from the macro cell 205) as an additional non-cumulative TPC command for PUCCH that is applied instead of the currently specified TPC field. For other PUCCH transmissions targeted to the small cell 220 c, PC for PUCCH may be applied as specified in existing 3GPP Rel-10 or Rel-11 specifications.
A general process for UL PC for a UE 215 that incorporates one or more of the embodiments above related to Option 2b may be described with respect to FIG. 8. Initially the CL PC process for PUCCH may be identified at 800. Next, the TPC command for the CL PC process may be identified at 805, for example in a DCI field of a DL PDCCH or ePDCCH transmission. Finally, the TPC command may be used as a non-cumulative adjustment to adjust the UL PUCCH transmission power at 810. As described above, the adjustment may be to compensate for the use of a non-ideal pathloss reference.
UL PC for UEs in Sce 2a and Sce 2b Networks with CA-PUSCH
Some Sce 2A and Sce 2B networks may be configured with DL CA. Specifically, in some Sce 2A and Sce 2B networks, DL or UL signals may be transmitted from eNB 210, eNB 225 c, or UE 215 respectively using more than one carrier or channel. In embodiments CA transmissions may be on two separate cells or channels, a primary cell (PCell) and a secondary cell (SCell). In embodiments, if UE 215 is configured with DL and UL CA, then legacy UL PC for PUSCH transmissions such as that defined in Rel-10 or Rel-11 specifications may be supported using self-scheduling for each CC.
UL PC for UEs in Sce 2a and Sce 2b Networks with CA-PUCCH
In some Sce 2a or Sce 2b networks, UE 215 may be configured to transmit UL PUCCH transmissions on the SCell. In some embodiments the UE 215 may be configured with a SIB-2 linkage between macro cell 205 DL PCell transmissions and small cell 220 c UL PCell transmissions.
If multiple UL PUCCH transmissions from the multiple serving cells in CA are allowed, each UL PUCCH transmission from a serving cell may be identified as corresponding to the serving cell. For example, if UE 215 transmits HARQ-ACK information in a UL PUCCH transmission, and the HARQ-ACK information corresponds to DL data received in a DL PDSCH transmission from a DL serving cell such as macro cell 205, or the UE 215 transmits CSI information in a UL PUCCH transmission, the pathloss reference for PC of the UL PUCCH transmission may be derived from the DL serving cell. In embodiments, this PC process may mean that in some embodiments it may not be necessary or useful to forward UL control information (UCI) from the macro cell 205 to small cell 220 c, or vice-versa.
When PUCCH format 1b, which may have channel selection enabled, is used to transmit a UL PUCCH transmission with HARQ-ACK information in a Sce 2a or Sce 2b network with CA, some PUCCH resource may be derived from the CCE or enhanced CCE (eCCE) index of a DL PDCCH or ePDCCH transmission transmitted on the PCell. Other PUCCH resources may be derived from the RRC signaling. The network 200 may configure the PUCCH resources so that the UL PUCCH transmission may be transmitted on an SCell.
For example, if both a PCell such as macro cell 205 and a secondary cell such as small cell 220 c are configured by multiple-input multiple-output (MIMO), for example with two transmit beamforming systems (TBs), then four HARQ-ACK UL PUCCH transmissions, HARQ-ACK (0), HARQ-ACK (1), HARQ-ACK (2), and HARQ-ACK (3) may be transmitted. HARQ-ACK (0) and HARQ-ACK (1) may be related to the PCell, while HARQ-ACK (2) and HARQ-ACK (3) may be related to the SCell.
In embodiments where cross-carrier scheduling is not configured, the PUCCH resources n⁽¹⁾ _PUCCH,0and n⁽¹⁾ _PUCCH,1may be derived from the CCE or eCCE index of a DL PDCCH or ePDCCH transmission of the PCell, and the PUCCH resources n⁽¹⁾ _PUCCH,2and n⁽¹⁾ _PUCCH,3may be given by RRC signaling. In this example, because n⁽¹⁾ _PUCCH,2and n⁽¹⁾ _PUCCH,3may be for the PUCCH resources related to UL PUCCH transmissions on the UL SCell, the UL PUCCH transmission that uses PUCCH resources n⁽¹⁾ _PUCCH,2and n⁽¹⁾ _PUCCH,3may be transmitted on the SCell. In this embodiment, a CA channel selection operation may be performed across the various serving cells. When the PUCCH resource for UL PUCCH transmission is for the UL PCell, the pathloss reference for PUCCH PC may be derived from the DL PCell. When the PUCCH resource for UL PUCCH transmissions is for the UL SCell, the pathloss reference for PUCCH PC may be derived from the DL SCell.
In some embodiments, TPC commands for UL PUCCH transmissions targeting small cell 220 c may not be carried by a DCI field in a DL PDCCH or ePDCCH transmission from the small cell 220 c, which may be the DL SCell. Specifically, the “TPC for PUCCH” field, which may be a field of the DCI, may be reinterpreted in this case as the ACK-NACK resource indicator (ARI), which may indicate PUCCH format 1a/1b or PUCCH format 3 resource, for example for FDD networks. In other embodiments, for example networks with non-ideal backhaul, it may not be possible to transmit TPC commands for PUCCH in a DL transmission or DL CC from the macro cell 205 in a timely fashion.
Instead of transmitting the TPC commands, in some embodiments a new 2-bit field may be added to DCI fields with DCI formats 1A, 1B, 1D, 1, 2A, 2, 2B, 2C, or 2D for an accumulative or non-cumulative PUCCH TPC command that is carried in DL PDCCH or ePDCCH transmissions on the SCell. In other embodiments, for example where common search space (CSS) is supported for ePDCCH, then the new field may also be considered for DCI formats 3 or 3A to facilitate group power control for groups of UEs.
If multiple UL PUCCH transmissions with implicit resource allocation corresponding to independent PDSCH scheduling using DL PDCCH or ePDCCH transmissions from the macro cell 205 (i.e. the PCell) and small cell 220 c (i.e. the SCell) to multiple serving cells in CA are allowed by the network 200, then it may not be necessary or desirable to add the additional TPC bits as described above. In this embodiment, UL PUCCH resources may be derived implicitly for both the PCell and the SCell. In other words, dynamic PUCCH resource for the PCell and the SCell may be implicitly derived from the DL PDCCH or ePDCCH transmissions transmitted by the PCell or SCell, respectively. In these embodiments, it may be sufficient to restore the TPC fields in a DL PDCCH or ePDCCH transmission that indicate scheduling of a DL PDSCH transmission transmitted on an SCell as real TPC which is not used as ARI, as described above. In this embodiment, the used PUCCH format for a UL PUCCH transmission with HARQ-ACK information may be PUCCH format 1a or 1b, or PUCCH format 1b with channel selection.
UL PC for UEs in Sce 2a and Sce 2b Networks without CA
In embodiments where a Sce 2a or Sce 2b network has decoupled DL-UL association and the network is not configured with CA, the network may have a SIB-2 linkage between DL parameters of the macro cell 205 and UL parameters of the small cell 220 c. However, in this embodiment, all UL control information may need to be communicated by the small cell 220 c to the macro cell 205 via backhaul links 230 and 235. As a result, delivery of time-sensitive information such as DL HARQ-ACK information to the macro cell 205 may be delayed if the backhaul links are susceptible to delays. Therefore, in this embodiment, UL PC for PUSCH, PUCCH, and SRS may either rely on OL PC or a less dynamic version of CL PC based on a “semi-static” PC process maintained at the small cell 220 c and communicated over the delay-prone backhaul to the macro cell 205.
Embodiments of the present disclosure may be implemented into a system using any suitable hardware and/or software to configure as desired. FIG. 9 schematically illustrates an example system 900 that may be used to practice various embodiments described herein. FIG. 9 illustrates, for one embodiment, an example system 900 having one or more processor(s) 905, system control module 910 coupled to at least one of the processor(s) 905, system memory 915 coupled to system control module 910, non-volatile memory (NVM)/storage 920 coupled to system control module 910, and one or more communications interface(s) 925 coupled to system control module 910.
In some embodiments, the system 900 may be capable of functioning as the UE 110 or 215 as described herein. In other embodiments, the system 900 may be capable of functioning as one of eNBs 105, 210, 225 a, 225 b, or 225 c, as described herein. In some embodiments, the system 900 may include one or more computer-readable media (e.g., system memory or NVM/storage 920) having instructions and one or more processors (e.g., processor(s) 905) coupled with the one or more computer-readable media and configured to execute the instructions to implement a module to perform actions described herein.
System control module 910 for one embodiment may include any suitable interface controllers to provide for any suitable interface to at least one of the processor(s) 905 and/or to any suitable device or component in communication with system control module 910.
System control module 910 may include memory controller module 930 to provide an interface to system memory 915. The memory controller module 930 may be a hardware module, a software module, and/or a firmware module.
System memory 915 may be used to load and store data and/or instructions, for example, for system 900. System memory 915 for one embodiment may include any suitable volatile memory, such as suitable DRAM, for example. In some embodiments, the system memory 915 may include double data rate type four synchronous dynamic random-access memory (DDR4 SDRAM).
System control module 910 for one embodiment may include one or more input/output (I/O) controller(s) to provide an interface to NVM/storage 920 and communications interface(s) 925.
The NVM/storage 920 may be used to store data and/or instructions, for example. NVM/storage 920 may include any suitable non-volatile memory, such as flash memory, for example, and/or may include any suitable non-volatile storage device(s), such as one or more hard disk drive(s) (HDD(s)), one or more compact disc (CD) drive(s), and/or one or more digital versatile disc (DVD) drive(s), for example.
The NVM/storage 920 may include a storage resource physically part of a device on which the system 900 may be installed or it may be accessible by, but not necessarily a part of, the device. For example, the NVM/storage 920 may be accessed over a network via the communications interface(s) 925.
Communications interface(s) 925 may provide an interface for system 900 to communicate over one or more network(s) and/or with any other suitable device. The system 900 may wirelessly communicate with the one or more components of the wireless network in accordance with any of one or more wireless network standards and/or protocols. In some embodiments the communications interface(s) 925 may include the transceiver modules 122 or 135.
For one embodiment, at least one of the processor(s) 905 may be packaged together with logic for one or more controller(s) of system control module 910, e.g., memory controller module 930. For one embodiment, at least one of the processor(s) 905 may be packaged together with logic for one or more controllers of system control module 910 to form a System in Package (SiP). For one embodiment, at least one of the processor(s) 905 may be integrated on the same die with logic for one or more controller(s) of system control module 910. For one embodiment, at least one of the processor(s) 905 may be integrated on the same die with logic for one or more controller(s) of system control module 910 to form a System on Chip (SoC).
In some embodiments the processor(s) 905 may include or otherwise be coupled with one or more of a graphics processor (GPU) (not shown), a digital signal processor (DSP) (not shown), wireless modem (not shown), digital camera or multimedia circuitry (not shown), sensor circuitry (not shown), display circuitry (not shown), and/or GPS circuitry (not shown).
In various embodiments, the system 900 may be, but is not limited to, a server, a workstation, a desktop computing device, or a mobile computing device (e.g., a laptop computing device, a handheld computing device, a tablet, a netbook, a smart phone, a gaming console, etc.). In various embodiments, the system 900 may have more or less components, and/or different architectures. For example, in some embodiments, the system 900 includes one or more of a camera, a keyboard, liquid crystal display (LCD) screen (including touch screen displays), non-volatile memory port, multiple antennas, graphics chip, application-specific integrated circuit (ASIC), and speakers.

Examples

A first example (Example 1) may include a method comprising: receiving, by a user equipment (UE), a downlink transmission from a first cell; transmitting, by the UE responsive to the downlink transmission, a physical uplink shared channel (PUSCH) transmission; receiving, by the UE responsive to the PUSCH transmission, an uplink (UL) grant indicating a re-transmission of the PUSCH transmission; and transmitting, by the UE responsive to the UL grant, the PUSCH transmission.
Example 2 may include the method of example 1, wherein the UL grant is a UL grant from the first cell.
Example 3 may include the method of example 2, wherein the UL grant is received on a physical downlink control channel (PDCCH) or an enhanced PDCCH (ePDCCH) of the first cell.
Example 4 may include the method of example 1, wherein the UL grant is a UL grant from a second cell.
Example 5 may include the method of example 4, wherein the UL grant is received on a physical downlink control channel (PDCCH) or an enhanced PDCCH (ePDCCH) of the second cell.
Example 6 may include the method of any of examples 1-5, wherein the first cell or the second cell are configured to not transmit an indicator to the UE on a physical hybrid automatic repeat request indicator channel (PHICH) of the first cell or a PHICH of the second cell.
Example 7 may include an apparatus comprising means to perform the method of any of examples 1-6.
Example 8 may include one or more non-statutory computer readable media comprising instructions to, upon executions of the instructions by one or more processors of a computing device, perform the method of any of examples 1-6.
Example 9 may include an apparatus to be employed in a user equipment (UE), the apparatus comprising: receiver circuitry to receive a downlink transmission from a first cell; transmitter circuitry to transmit, responsive to the downlink transmission, a physical uplink shared channel (PUSCH) transmission; wherein the receiver circuitry is further to receive, responsive to the PUSCH transmission, an uplink (UL) grant indicating a re-transmission of the PUSCH transmission; and the transmitter circuitry is further to transmit, responsive to the UL grant, the PUSCH transmission.
Example 10 may include the apparatus of example 9, wherein the UL grant is a UL grant from the first cell.
Example 11 may include the apparatus of example 10, wherein the receiver circuitry is further to receive the UL grant on a physical downlink control channel (PDCCH) or an enhanced PDCCH (ePDCCH) of the first cell.
Example 12 may include the apparatus of example 9, wherein the UL grant is a UL grant from a second cell.
Example 13 may include the apparatus of example 12, wherein the receiver circuitry is further to receive the UL grant on a physical downlink control channel (PDCCH) or an enhanced PDCCH (ePDCCH) of the second cell.
Example 14 may include the apparatus of any of examples 9-13, wherein the first cell or the second cell are configured to not transmit an indicator to the UE on a physical hybrid automatic repeat request indicator channel (PHICH) of the first cell or a PHICH of the second cell.
Example 15 may include an apparatus comprising: a communication module to: receive a physical downlink control channel (PDCCH) or enhanced PDCCH (ePDCCH) transmission from a first cell; and transmit, responsive to the PDCCH or ePDCCH transmission, a physical uplink shared channel (PUSCH) transmission; and a re-transmission module to: facilitate, in response to identification of an uplink (UL) grant received in a downlink (DL) transmission and independent of a physical hybrid automatic repeat request indicator channel (PHICH) transmission from the first cell or a second cell, a re-transmission of a previously-transmitted PUSCH transmission.
Example 16 may include the apparatus of example 15, wherein the UL grant is a UL grant from the first cell.
Example 17 may include the apparatus of example 16, wherein the communication module is further to receive the UL grant in the PDCCH or ePDCCH transmission of the first cell.
Example 18 may include the apparatus of example 15, wherein the UL grant is a UL grant from the second cell.
Example 19 may include the apparatus of example 18, wherein the communication is further to receive the UL grant in a physical downlink control channel (PDCCH) or an enhanced PDCCH (ePDCCH) of the second cell.
Example 20 may include the apparatus of example 15, wherein the communication module is further to: receive an indication in a radio resource control (RRC) signal from the first cell; and receive, based at least in part on the indication, a PHICH signal from the second cell.
Example 21 may include the apparatus of example 20, wherein the indication, includes an indication of a physical cell identifier (PCI), a number of orthogonal frequency division multiplexing (OFDM) symbols for a PDCCH transmission, a starting symbol for a physical downlink shared channel (PDSCH) transmission, a duration of a PHICH transmission, or a configuration parametera of a physical broadcast channel (PBCH) transmission that may include one or more antenna port (AP) configuration.
Example 22 may include the apparatus of any of examples 15-21, wherein the communication module is a baseband module and the apparatus further comprises a multi-mode transceiver chip that includes the baseband module, the re-transmission module, and a power management unit to control power provided to the baseband and re-transmission modules.
Example 23 may include a method comprising: receiving, by a computing device, a physical downlink control channel (PDCCH) or enhanced PDCCH (ePDCCH) transmission from a first cell; transmitting, by the computing device responsive to the PDCCH or ePDCCH transmission, a physical uplink shared channel (PUSCH) transmission; and facilitating, by the computing device in response to identification of an uplink (UL) grant received in a downlink (DL) transmission and independent of a physical hybrid automatic repeat request indicator channel (PHICH) transmission from the first cell or a second cell, a re-transmission of a previously-transmitted PUSCH transmission.
Example 24 may include the method of example 23, wherein the UL grant is a UL grant from the first cell.
Example 25 may include the method of example 24, further comprising receiving, by the computing device, the UL grant in the PDCCH or ePDCCH transmission of the first cell.
Example 26 may include the method of example 23, wherein the UL grant is a UL grant from the second cell.
Example 27 may include the method of example 26, further comprising receiving, by the computing device, the UL grant in a physical downlink control channel (PDCCH) or an enhanced PDCCH (ePDCCH) of the second cell.
Example 28 may include the method of example 23, further comprising receiving, by the computing device, an indication in a radio resource control (RRC) signal from the first cell; and receiving, by the computing device based at least in part on the indication, a PHICH signal from the second cell.
Example 29 may include the method of example 28, wherein the indication includes an indication of a physical cell identifier (PCI), a number of orthogonal frequency division multiplexing (OFDM) symbols for a PDCCH transmission, a starting symbol for a physical downlink shared channel (PDSCH) transmission, a duration of a PHICH transmission, or a configuration parametera of a physical broadcast channel (PBCH) transmission that may include one or more antenna port (AP) configuration.
Example 30 may include an apparatus comprising means to perform the method of any of examples 23-29.
Example 31 may include one or more non-statutory computer readable media comprising instructions to, upon executions of the instructions by one or more processors of a computing device, perform the method of any of examples 23-29.
Example 32 may include a method comprising: identifying, by a user equipment (UE) configured to transmit uplink signals using one or more power control (PC) processes, one or more closed loop (CL) PC processes for physical uplink shared channel (PUSCH) transmissions of the UE; identifying, by the UE, a second CL PC process for a first physical uplink control channel (PUCCH) transmission from the UE; and identifying, by the UE, a third CL PC process for a second PUCCH transmission from the UE that is concurrent with the second CL PC process.
Example 33 may include the method of example 32, wherein the second or third CL PC process is based on a PUCCH format of the first or second PUCCH transmissions.
Example 34 may include the method of examples 32 or 33, further comprising identifying, by the UE, a pathloss reference based at least in part on a first cell.
Example 35 may include the method of examples 32 or 33, further comprising identifying, by the UE, a first cell or a second cell as a pathloss reference based at least in part on a radio resource control (RRC) signal received by the UE.
Example 36 may include the method of example 35, further comprising receiving, by the UE, a first value for open loop (OL) PC parameters, the first value associated with the use of the first cell as a pathloss reference; and receiving, by the UE, a second value for OL PC parameters, the second value associated with the use of the first cell as a pathloss reference; wherein the OL PC parameters include P_O _— _PUCCH, P_O _— _NOMINAL _— _PUCCH, or P_O _— _UE _— _PUCCH.
Example 37 may include the method of example 35, further comprising identifying, by the UE in a transmission received from the eNB of the first cell, a transmit power control (TPC) command; and changing, by the UE, a transmit power of the first CL PC, second CL PC, or third CL PC based at least in part on the received TPC command.
Example 38 may include an apparatus comprising means to perform the method of any of examples 32-37.
Example 39 may include one or more non-statutory computer readable media comprising instructions to, upon executions of the instructions by one or more processors of a computing device, perform the method of any of examples 32-37.
Example 40 may include an apparatus to be employed in a user equipment (UE), the apparatus comprising: transmitter circuitry to transmit uplink signals using one or more power control (PC) processes; and a processor coupled with the transmitter circuitry, the processor to: identify one or more closed loop (CL) PC processes for physical uplink shared channel (PUSCH) transmissions of the UE; identify a second CL PC process for a first physical uplink control channel (PUCCH) transmission from the UE; and identify a third CL PC process for a second PUCCH transmission from the UE that is concurrent with the second CL PC process.
Example 41 may include the apparatus of example 40, wherein the second or third CL PC process is based on a PUCCH format of the first or second PUCCH transmissions.
Example 42 may include the apparatus of examples 40 or 41, wherein the processor is further to a pathloss reference based at least in part on a first cell.
Example 43 may include the apparatus of examples 40 or 41, wherein the processor is further to a first cell or a second cell as a pathloss reference based at least in part on a radio resource control (RRC) signal received by the UE.
Example 44 may include the method of example 43, further comprising receiving, by the UE, a first value for open loop (OL) PC parameters, the first value associated with the use of the first cell as a pathloss reference; and receiving, by the UE, a second value for OL PC parameters, the second value associated with the use of the first cell as a pathloss reference; wherein the OL PC parameters include P_O _— _PUCCH, P_O _— _NOMINAL _— _PUCCH, or P_O _— _UE _— _PUCCH.
Example 45 may include the method of example 43, further comprising identifying, by the UE in a transmission received from the eNB of the first cell, a transmit power control (TPC) command; and changing, by the UE, a transmit power of the first CL PC, second CL PC, or third CL PC based at least in part on the received TPC command.
Example 46 may include one or more non-transitory computer readable media comprising instructions configured to cause a user equipment (UE) configured to receive downlink transmissions from a first cell of a wireless network and transmit uplink transmissions, upon execution of the instructions by the UE, to: identify a closed loop (CL) power control (PC) process for a physical uplink control channel (PUCCH) of the UE; identify, based on a downlink (DL) signal from the first cell, a non-cumulative transmit power control (TPC) command for the CL PC process; and adjust a transmission power value of a PUCCH transmission based at least in part on a value of the non-cumulative TPC command.
Example 47 may include the one or more non-transitory computer readable media of example 46, wherein the instructions further comprise instructions to adjust the transmission power value of the PUCCH transmission based at least in part on pathloss reference of the PUCCH transmission.
Example 48 may include the one or more non-transitory computer readable media of example 46, wherein the PUCCH CL PC process is maintained at a second cell and the PUCCH transmission is a PUCCH transmission targeted to the first cell.
Example 49 may include the one or more non-transitory computer readable media of example 46, wherein the PUCCH CL PC process is maintained at the first cell and the PUCCH transmission is a PUCCH transmission targeted to a second cell.
Example 50 may include the one or more non-transitory computer readable media of any of examples 46-49, wherein the PUCCH transmission is configured according to a delay-sensitive third generation partnership project (3GPP) PUCCH format.
Example 51 may include a method comprising: identifying, by a user equipment (UE) configured to receive downlink transmissions from a first cell of a wireless network and transmit uplink transmissions, closed loop (CL) power control (PC) process for a physical uplink control channel (PUCCH) of the UE; identifying, by the UE based on a downlink (DL) signal from the first cell, a non-cumulative transmit power control (TPC) command for the CL PC process; and adjusting, by the UE, a transmission power value of a PUCCH transmission based at least in part on a value of the non-cumulative TPC command.
Example 52 may include the method of example 51, further comprising adjusting, by the UE, the transmission power value of the PUCCH transmission based at least in part on pathloss reference of the PUCCH transmission.
Example 53 may include the method of example 51, wherein the PUCCH CL PC process is maintained at a second cell and the PUCCH transmission is a PUCCH transmission targeted to the first cell.
Example 54 may include the method of example 51, wherein the PUCCH CL PC process is maintained at the first cell and the PUCCH transmission is a PUCCH transmission targeted to a second cell.
Example 55 may include the method of any of examples 51-54, wherein the PUCCH transmission is configured according to a delay-sensitive third generation partnership project (3GPP) PUCCH format.
Example 56 may include an apparatus comprising means to perform the method of any of examples 51-55.
Example 57 may include an apparatus to be employed in a user equipment (UE), the apparatus comprising: a transceiver module to receive downlink transmissions from a first cell of a wireless network and transmit uplink transmissions; and a processor coupled with the transceiver module, the processor to: identify a closed loop (CL) power control (PC) process for a physical uplink control channel (PUCCH) of the UE; identify, based on a downlink (DL) signal from the first cell, a non-cumulative transmit power control (TPC) command for the CL PC process; and adjust a transmission power value of a PUCCH transmission based at least in part on a value of the non-cumulative TPC command.
Example 58 may include the apparatus of example 57, wherein the processor is further to adjust the transmission power value of the PUCCH transmission based at least in part on pathloss reference of the PUCCH transmission.
Example 59 may include the apparatus of example 57, wherein the PUCCH CL PC process is maintained at a second cell and the PUCCH transmission is a PUCCH transmission targeted to the first cell.
Example 60 may include the apparatus of example 57, wherein the PUCCH CL PC process is maintained at the first cell and the PUCCH transmission is a PUCCH transmission targeted to a second cell.
Example 61 may include the apparatus of any of examples 57-60, wherein the PUCCH transmission is configured according to a delay-sensitive third generation partnership project (3GPP) PUCCH format.
Although certain embodiments have been illustrated and described herein for purposes of description, this application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that embodiments described herein be limited only by the claims.
Where the disclosure recites “a” or “a first” element or the equivalent thereof, such disclosure includes one or more such elements, neither requiring nor excluding two or more such elements. Further, ordinal indicators (e.g., first, second or third) for identified elements are used to distinguish between the elements, and do not indicate or imply a required or limited number of such elements, nor do they indicate a particular position or order of such elements unless otherwise specifically stated.

Claims

1. A method comprising:

receiving, by a user equipment (UE), a downlink transmission from a first cell;

transmitting, by the UE responsive to the downlink transmission, a physical uplink shared channel (PUSCH) transmission;

receiving, by the UE responsive to the PUSCH transmission, an uplink (UL) grant indicating a re-transmission of the PUSCH transmission; and

transmitting, by the UE responsive to the UL grant, the PUSCH transmission.

2. The method of claim 1, wherein the UL grant is a UL grant from the first cell.

3. The method of claim 2, wherein the UL grant is received on a physical downlink control channel (PDCCH) or an enhanced PDCCH (ePDCCH) of the first cell.

4. The method of claim 1, wherein the UL grant is a UL grant from a second cell.

5. The method of claim 4, wherein the UL grant is received on a physical downlink control channel (PDCCH) or an enhanced PDCCH (ePDCCH) of the second cell.

6. The method of claim 1, wherein the first cell or the second cell are configured to not transmit an indicator to the UE on a physical hybrid automatic repeat request indicator channel (PHICH) of the first cell or a PHICH of the second cell.

7. An apparatus comprising:

a communication module to:

receive a physical downlink control channel (PDCCH) or enhanced PDCCH (ePDCCH) transmission from a first cell; and

transmit, responsive to the PDCCH or ePDCCH transmission, a physical uplink shared channel (PUSCH) transmission; and

a re-transmission module to:

facilitate, in response to identification of an uplink (UL) grant received in a downlink (DL) transmission and independent of a physical hybrid automatic repeat request indicator channel (PHICH) transmission from the first cell or a second cell, a re-transmission of a previously-transmitted PUSCH transmission.

8. The apparatus of claim 7, wherein the UL grant is a UL grant from the first cell.

9. The apparatus of claim 8, wherein the communication module is further to receive the UL grant in the PDCCH or ePDCCH transmission of the first cell.

10. The apparatus of claim 7, wherein the UL grant is a UL grant from the second cell.

11. The apparatus of claim 10, wherein the communication module is further to receive the UL grant in a physical downlink control channel (PDCCH) or an enhanced PDCCH (ePDCCH) of the second cell.

12. The apparatus of claim 7, wherein the communication module is further to:

receive an indication in a radio resource control (RRC) signal from the first cell; and

receive, based at least in part on the indication, a PHICH signal from the second cell.

13. The apparatus of claim 12, wherein the indication, includes an indication of a physical cell identifier (PCI), a number of orthogonal frequency division multiplexing (OFDM) symbols for a PDCCH transmission, a starting symbol for a physical downlink shared channel (PDSCH) transmission, a duration of a PHICH transmission, or a configuration parametera of a physical broadcast channel (PBCH) transmission that may include one or more antenna port (AP) configuration.

14. The apparatus of claim 7, wherein the communication module is a baseband module and the apparatus further comprises a multi-mode transceiver chip that includes the baseband module, the re-transmission module, and a power management unit to control power provided to the baseband and re-transmission modules.

15. A method comprising:

identifying, by a user equipment (UE) configured to transmit uplink signals using one or more power control (PC) processes, one or more closed loop (CL) PC processes for physical uplink shared channel (PUSCH) transmissions of the UE;

identifying, by the UE, a second CL PC process for a first physical uplink control channel (PUCCH) transmission from the UE; and

identifying, by the UE, a third CL PC process for a second PUCCH transmission from the UE that is concurrent with the second CL PC process.

16. The method of claim 15, wherein the second or third CL PC process is based on a PUCCH format of the first or second PUCCH transmissions.

17. The method of claim 15, further comprising identifying, by the UE, a pathloss reference based at least in part on a first cell.

18. The method of claim 15, further comprising identifying, by the UE, a first cell or a second cell as a pathloss reference based at least in part on a radio resource control (RRC) signal received by the UE.

19. The method of claim 18, further comprising receiving, by the UE, a first value for open loop (OL) PC parameters, the first value associated with the use of the first cell as a pathloss reference; and

receiving, by the UE, a second value for OL PC parameters, the second value associated with the use of the first cell as a pathloss reference;

wherein the OL PC parameters include P_O _— _PUCCH, P_O _— _NOMINAL _— _PUCCH, or P_O _— _UE _— _PUCCH.

20. The method of claim 18, further comprising identifying, by the UE in a transmission received from the eNB of the first cell, a transmit power control (TPC) command; and

changing, by the UE, a transmit power of the first CL PC, second CL PC, or third CL PC based at least in part on the received TPC command.

21. One or more non-transitory computer readable media comprising instructions configured to cause a user equipment (UE) configured to receive downlink transmissions from a first cell of a wireless network and transmit uplink transmissions, upon execution of the instructions by the UE, to:

identify a closed loop (CL) power control (PC) process for a physical uplink control channel (PUCCH) of the UE;

identify, based on a downlink (DL) signal from the first cell, a non-cumulative transmit power control (TPC) command for the CL PC process; and

adjust a transmission power value of a PUCCH transmission based at least in part on a value of the non-cumulative TPC command.

22. The one or more non-transitory computer readable media of claim 21, wherein the instructions further comprise instructions to adjust the transmission power value of the PUCCH transmission based at least in part on pathloss reference of the PUCCH transmission.

23. The one or more non-transitory computer readable media of claim 21, wherein the PUCCH CL PC process is maintained at a second cell and the PUCCH transmission is a PUCCH transmission targeted to the first cell.

24. The one or more non-transitory computer readable media of claim 21, wherein the PUCCH CL PC process is maintained at the first cell and the PUCCH transmission is a PUCCH transmission targeted to a second cell.

25. The one or more non-transitory computer readable media of claim 21, wherein the PUCCH transmission is configured according to a delay-sensitive third generation partnership project (3GPP) PUCCH format.