HK1192991A - Base station, user equipment and methods therein for control timing configuration assignment in a multiple cell communications network - Google Patents

Description

Base station, user equipment and methods thereof for controlling timing configuration assignment in a multi-cell communication network

Technical Field

Example embodiments relate to a base station and user equipment for assigning and implementing control timing configuration numbers for control timing in a multi-cell communication network and methods thereof.

Background

Long term evolution system

Long Term Evolution (LTE) uses Orthogonal Frequency Division Multiplexing (OFDM) in the downlink direction and Discrete Fourier Transform (DFT) -spread OFDM in the uplink direction. The basic LTE downlink physical resource can thus be seen as a time-frequency grid as shown in fig. 1, where each resource element corresponds to one OFDM subcarrier during one OFDM symbol interval. As shown in fig. 2, in the time domain, LTE downlink transmissions may be organized into radio frames of 10ms, where each radio frame consists of ten equally sized subframes of length Tsubframe =1 ms.

In addition, resource allocation in LTE is generally described in terms of resource blocks, where a resource block corresponds to one slot (0.5 ms) in the time domain and 12 subcarriers in the frequency domain. Starting with 0 from one end of the system bandwidth, resource blocks are numbered in the frequency domain.

Downlink transmissions are dynamically scheduled, i.e. in each subframe, the base station transmits control information about to which user equipment data is transmitted in the current downlink subframe and on which resource blocks the data is transmitted. This control signaling is typically transmitted in the first 1,2, 3 or 4 OFDM symbols in each subframe. A downlink system with 3 OFDM symbols for control purposes is illustrated in fig. 3. The dynamic scheduling information is communicated to the user equipment via a Physical Downlink Control Channel (PDCCH) transmitted in the control region. After successfully decoding the PDCCH, the user equipment performs reception of a Physical Downlink Shared Channel (PDSCH) or transmission of a Physical Uplink Shared Channel (PUSCH) according to a predetermined timing specified in the LTE specification.

LTE uses hybrid automatic repeat request (HARQ), where after receiving downlink data in a subframe, the user equipment attempts to decode it and reports to the base station via a Physical Uplink Control Channel (PUCCH) whether the decoding was successful (transmission Acknowledgement (ACK)) or unsuccessful (transmission Negative Acknowledgement (NACK)). In the event that a decoding attempt is unsuccessful, the base station may retransmit the erroneous data. Similarly, the base station may indicate to the UE via a physical hybrid ARQ indicator channel (PHCIH) that the decoding of the PUSCH is successful (transmission of ACK) or unsuccessful (transmission of NACK).

Uplink control signaling from the user equipment to the base station may include (1) HARQ acknowledgements for received downlink data; (2) user equipment reports related to downlink channel conditions used as assistance for downlink scheduling; and/or (3) a scheduling request indicating that the mobile user equipment requires uplink resources for uplink data transmission.

If the mobile user equipment has not been assigned uplink resources for data transmission, then L1/L2 control information, such as channel state reports, HARQ acknowledgements and scheduling requests, are transmitted in the uplink resources, e.g., specially assigned resource blocks for uplink L1/L2 control on the release 8 (Rel-8) PUCCH. As shown in fig. 4, these uplink resources are located at the edge of the total available transmission bandwidth. Each such uplink resource comprises 12 "subcarriers" (one resource block) in each of two slots of an uplink subframe. To provide frequency diversity, these frequency resources are frequency hopped at a slot boundary, indicated by the arrows, i.e. one "resource" comprises 12 subcarriers of the upper part of the spectrum within the first slot of the subframe and equally sized resources of the lower part of the spectrum during the second slot of the subframe or vice versa. If more resources are needed for uplink L1/L2 control signaling, e.g., in case of a large total transmission bandwidth supporting a large number of users, additional resource blocks may be assigned next to the previously assigned resource blocks.

Carrier aggregation

LTE release 10 (Rel-10) has recently been standardized to support bandwidths greater than 20 MHz. One requirement for LTE Rel-10 is to ensure backward compatibility with LTE Rel-8. This may also include spectrum compatibility. This would mean that an LTE Rel-10 carrier wider than 20MHz should appear as multiple LTE carriers to an LTE Rel-8 user equipment. Each such carrier may be referred to as a Component Carrier (CC). Especially for early LTE Rel-10 deployments, it can be expected that there will be a smaller number of LTE Rel-10 capable user equipments compared to a large number of LTE legacy user equipments. Therefore, it may be useful for legacy user equipments to also guarantee efficient use of wide carriers, i.e. it is possible to implement carriers where legacy user equipments may be scheduled in all parts of the wideband LTE Rel-10 carrier. A straightforward way to achieve this would be by means of Carrier Aggregation (CA). CA means that an LTE Rel-10 user equipment can receive multiple CCs, where a CC has, or at least possibly has, the same structure as a Rel-8 carrier. CA is illustrated in fig. 5.

The number of aggregated CCs and the bandwidth of individual CCs may be different for uplink and downlink. The symmetric configuration refers to a case in which the number of CCs in the downlink and uplink is the same, and the asymmetric configuration refers to a case in which the number of CCs is different. It should be noted that the number of CCs configured in a cell may be different from the number of CCs seen by a user equipment. Although the network configuration is configured with the same number of uplink and downlink CCs, the user equipment may support more downlink CCs than uplink CCs, for example.

During initial access, LTE Rel-10 user equipment behaves similar to LTE Rel-8 user equipment. Upon successful connection to the network, the user equipment may be configured (according to its own capabilities and network) with additional CCs for uplink and downlink. The configuration is based on Radio Resource Control (RRC). Due to the heavy signaling and the rather slow speed of RRC signaling, it is envisaged that multiple CCs may be configured to a user equipment, even if not all currently used. If the user equipment is configured on multiple CCs, this would mean that it has to monitor all downlink CCs for PDCCH and PDSCH. This means wider receiver bandwidth, higher sampling rate, etc., resulting in higher power consumption.

To alleviate the above described problem, LTE Rel-10 supports activation of CCs on top of a configuration. The user equipment monitors only configured and activated CCs for PDCCH and PDSCH. Since activation is based on a faster Medium Access Control (MAC) control element than RRC signaling, activation/deactivation may follow the number of CCs needed to meet current data rate requirements. Upon arrival of a large amount of data, multiple CCs are activated for data transmission and deactivated if no longer needed. All CCs except one CC (downlink (DL) primary CC (dlpcc)) may be deactivated. Thus, activation offers the possibility to configure multiple CCs, but activate them only on an as needed basis. Most of the time, the user equipment will have one or few CCs active resulting in lower reception bandwidth and hence lower battery consumption.

Scheduling of CCs may be done on PDCCH via downlink assignments. Information on the PDCCH may be formatted as a Downlink Control Information (DCI) message. In Rel-8, the user equipment may operate with only one downlink and one uplink CC. The association between downlink assignments, uplink grants and corresponding downlink and uplink CCs is clear. In Rel1-, two CA patterns should be distinguished. The first mode is very similar to the operation of multiple Rel-8 CCs, where the downlink assignment or uplink grant contained in a DCI message transmitted on a CC is valid for the downlink CC itself or for an associated (such as via cell-specific or user equipment-specific linking) uplink CC. The second mode of operation extends the DCI message with a Carrier Indicator Field (CIF). The DCI including the downlink assignment with the CIF is valid for the downlink CC indicated with the CIF, and the DCI including the uplink grant with the CIF is valid for the indicated uplink CC.

The DCI message for downlink assignment includes resource block assignment, parameters related to modulation and coding scheme, HARQ redundancy version, etc., among others. Most DCI formats for downlink assignment also include a bit field for a Transmit Power Control (TPC) command, in addition to those parameters related to the actual downlink transmission. These TPC commands are used to control the uplink power control behavior of the corresponding PUCCH, which is used to transmit HARQ feedback.

In Rel-10LTE, PUCCH transmissions are mapped onto one particular uplink CC, the Uplink (UL) primary CC (UL pcc). A user equipment configured with a single downlink CC (which is then a DL PCC) and an uplink CC (which is then a ul PCC) operates a dynamic ACK/NACK on PUCCH according to Rel-8. The first Control Channel Element (CCE) used to transmit PDCCH for downlink assignment determines the dynamic ACK/NACK resource on Rel-8 PUCCH. Since only one downlink CC cell is specifically linked with the UL PCC, no PUCCH collision may occur since all PDCCHs are transmitted using a different first CCE.

The CA PUCCH should be used when receiving downlink assignments on a single secondary cc (scc) or receiving multiple DL assignments. Downlink SCC assignments are not typical per se. The scheduler in the base station should strive to schedule a single downlink CC assignment on the DL PCC and try to deactivate the SCC if not needed. A possible scenario that may arise is that the base station schedules the user equipment on multiple downlink CCs comprising the PCC. If the user equipment misses all assignments except DL PCC assignments, it will use the Rel-8PUCCH instead of the CAPUCCH. To detect this error condition, the base station must monitor both the Rel-8PUCCH and the CA PUCCH.

In Rel-10LTE, the CA PUCCH format is based on the number of configured CCs. The configuration of the CC is based on RRC signaling. After successful reception/application of the new configuration, an acknowledgement message is transmitted back, making RRC signaling very secure.

Time division duplex

Transmissions and receptions from a node, e.g., a user equipment in a cellular system such as LTE, may be multiplexed in the frequency domain or in the time domain (or a combination thereof). Frequency Division Duplex (FDD) as shown on the left in fig. 6 means that downlink and uplink transmissions occur in different, substantially separate frequency bands. Time Division Duplex (TDD) as shown on the right in fig. 6 means that downlink and uplink transmissions occur in different, non-overlapping time slots. Thus, TDD may operate in unpaired spectrum, while FDD requires paired spectrum.

The structure of the transmitted signals in a communication system is typically organized in the form of a frame structure. For example, LTE uses ten equally sized subframes of length 1ms per radio frame as shown in fig. 7.

In case of FDD operation (upper part of fig. 7), there are two carrier frequencies, one for uplink transmission (fl) and one for downlink transmission (fDL). FDD may be full duplex or half duplex, at least for user equipment in a cellular communication system. In a full duplex case, the user equipment may transmit and receive simultaneously, whereas in half duplex operation, the user equipment may not be able to transmit and receive simultaneously (whereas the base station is able to receive/transmit simultaneously, e.g. receive from a user equipment while transmitting to another user equipment). In LTE, half-duplex user equipment monitors/receives on the downlink unless explicitly indicated to transmit in a certain subframe.

In the case of TDD operation (lower part of fig. 7), there may be only a single carrier frequency, and uplink and downlink transmissions are typically separated in time on a cell basis. Since the same carrier frequency is used for uplink and downlink transmissions, both the base station and the mobile user equipment need to switch from transmission to reception and vice versa. One aspect of any TDD system is the possibility to provide a sufficiently large guard time in which neither downlink nor uplink transmission occurs. This is needed to avoid interference between uplink and downlink transmissions. For LTE, this guard time is provided by a special subframe (subframe 1, and in some cases subframe 6) that is split into three parts: a downlink part (downlink pilot time gap (DwPTS)), a Guard Period (GP), and an uplink part (uplink pilot time gap (UpPTS)). The remaining subframes are allocated for uplink or downlink transmission.

Disclosure of Invention

It is an object of some of the example embodiments presented herein to provide an efficient means of assigning uplink-downlink configurations across all aggregated CCs. Thus, some of the example embodiments may be directed to a method in a base station for configuring control timing to and from a user equipment in a multi-cell communication network. The method comprises determining at least one timing configuration number for a plurality of aggregated cells of a multi-cell communication network. Each aggregated cell is associated with an uplink-downlink configuration number, wherein at least two uplink-downlink configuration numbers of the plurality of aggregated cells are not equal. The plurality of aggregated cells are associated with a user equipment. The method also includes assigning at least one timing configuration number to the user equipment.

Some of the example embodiments may be directed to a base station for configuring control timing to and from a user equipment in a multi-cell communication network. The base station includes: a determining unit configured to determine at least one timing configuration number for a plurality of aggregated cells of a multi-cell communication network. Each aggregated cell is associated with an uplink-downlink configuration number. At least two uplink-downlink configuration numbers of the plurality of aggregated cells are not equal. The plurality of aggregated cells are associated with a user equipment. The base station also includes: an assigning unit configured to assign at least one timing configuration number to the user equipment.

Some of the example embodiments may be directed to a method in a user equipment for configuring control timing for the user equipment in a multi-cell communication network. The method comprises receiving at least one timing configuration number for a plurality of aggregated cells of a multi-cell communication network from a base station. Each aggregated cell is associated with an uplink-downlink configuration number, and wherein at least two uplink-downlink configuration numbers of the plurality of aggregated cells are not equal. The plurality of aggregated cells are associated with a user equipment. The method also includes implementing control timing based on the at least one timing configuration number.

Some of the example embodiments may be directed to a user equipment for configuring control timing for a user equipment in a multi-cell communication network. The user equipment includes: a determining unit configured for receiving at least one timing configuration number for a plurality of aggregated cells of a multi-cell communication network from a base station, wherein each aggregated cell is associated with an uplink-downlink configuration number, and wherein at least two uplink-downlink configuration numbers of the plurality of aggregated cells are not equal. A plurality of aggregated cells are associated with a user equipment. The user equipment also includes: an implementation unit configured to implement control timing based on the at least one timing configuration number.

Drawings

The foregoing will be apparent from the following more particular description of example embodiments as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating example embodiments.

Fig. 1 is an illustrative example of LTE downlink physical resources;

fig. 2 is a schematic diagram of an LTE time domain structure;

fig. 3 is an illustration of a downlink subframe;

FIG. 4 is an illustrative example of uplink L1/L2 control signaling on Rel-8 PUCCH;

fig. 5 is an illustrative example of carrier aggregation;

FIG. 6 is an illustrative example of frequency division duplexing and time division duplexing;

fig. 7 is a schematic diagram of an uplink-downlink time/frequency structure of LTE for the case of FDD and TDD;

fig. 8 is a schematic diagram of different downlink/uplink configurations for the case of TDD;

fig. 9 is an illustrative example of uplink-downlink interference in TDD;

fig. 10 is an illustration of PDSCH a/N feedback timing for configuration 1 and configuration 2 cells;

fig. 11 is an illustration of PUSCH grant and a/N feedback timing for configuration 1 cell and configuration 2 cell;

fig. 12 is an illustration of PDSCH a/N feedback timing for configuration 1 and configuration 3 cells;

fig. 13 is an illustration of PUSCH grant and a/N feedback timing for configuration 1 cell and configuration 3 cell;

fig. 14 is an illustrative example of carrier aggregation for TDD cells with different uplink-downlink configurations;

fig. 15 is an illustrative example of a frame compatibility rating in accordance with some of the example embodiments;

fig. 16 is an illustration of aggregated PUSCH grants and a/N feedback timing for a configuration 1 cell as a Pcell and a configuration 2 cell as a Scell, in accordance with some of the example embodiments;

fig. 17 is an illustration of aggregated PUSCH grants and a/N feedback timing for a configuration 2 cell as a Pcell and a configuration 1 cell as a Scell, in accordance with some of the example embodiments;

fig. 18 is an illustration of aggregated PDSCH a/N feedback timing for configuration 1 and configuration 2 cells, according to some of the example embodiments;

fig. 19 is an illustration of aggregated PUSCH grants and a/N feedback timing for a configuration 1 cell as a Pcell and a configuration 3 cell as a Scell, in accordance with some of the example embodiments;

fig. 20 is a diagram of aggregated PUSCH grants and a/N feedback timing for a configuration 3 cell as a Pcell and a configuration 1 cell as a Scell, in accordance with some of the example embodiments;

fig. 21 is an illustration of aggregated PDSCH a/N feedback timing for configuration 1 cells and configuration 3 cells, according to some of the example embodiments;

fig. 22 is an illustrative example of timing of additional forward subframe DL scheduling PDCCH for a half-duplex UE with aggregation of configuration 1 and configuration 2 cells in support of some of the example embodiments;

fig. 23 is an illustrative example of timing of an additional forward subframe DL scheduling PDCCH supporting half-duplex UEs with aggregation of configuration 1 and configuration 3 cells, in accordance with some of the example embodiments;

fig. 24 is an illustrative example of timing of additional cross-carrier forward subframe DL scheduling PDCCH supporting full-duplex UEs with aggregation of configuration 1 cells as Pcell and configuration 2 cells as Scell, in accordance with some of the example embodiments;

fig. 25 is an illustrative example of timing of additional cross-carrier forward subframe DL scheduling PDCCH in support of full-duplex UEs with aggregation of configuration 1 and configuration 3 cells, in accordance with some of the example embodiments;

fig. 26 is a schematic diagram of a base station configured to perform example embodiments described herein;

FIG. 27 is a schematic diagram of a user device configured to perform example embodiments described herein;

fig. 28 is a flow chart depicting example operation of the base station of fig. 26; and

fig. 29 is a flow chart depicting example operation of the user device of fig. 27.

Detailed Description

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular components, units, techniques, etc. in order to provide a thorough understanding of the example embodiments. However, example embodiments may be practiced in other ways that depart from these specific details. In other instances, detailed descriptions of well-known methods and elements are omitted so as not to obscure the description of the example embodiments.

As part of the development of the example embodiments presented herein, a problem will first be identified and discussed. TDD allows asymmetry in the amount of resources allocated for uplink and downlink transmissions, respectively, by means of different downlink/uplink configurations. In LTE there are seven different configurations as shown in fig. 8. Note that in the following description, under the heading of 'tdd harq timing', a downlink subframe may mean a downlink subframe or a special subframe.

To avoid interference between downlink and uplink transmissions between different cells, neighbor cells should have the same downlink/uplink configuration. If this is not done, uplink transmissions in one cell may interfere with downlink transmissions in a neighbor cell and vice versa, as shown in fig. 9. Thus, the downlink/uplink asymmetry may not typically vary between cells, but rather be signaled as part of the system information and remain fixed for a long period of time.

The description provided herein is arranged as follows. An overview of the current system and method for controlling timing configuration is first presented under the heading 'existing system-TDD HARQ control timing'. The limitations of existing systems are then explored under the subheading 'problem with existing solutions'.

The basis of the example embodiment is then presented in the section entitled 'sub-frame timing compatibility', where a sub-frame timing compatibility hierarchy can be used to replace the complex configuration table (illustrated in 'existing system-TDDHARQ control timing'). An example of a control timing configuration assignment utilizing a sub-frame timing compatibility hierarchy is then provided in the subsection entitled 'configuration assignment'. Examples of control timing configuration assignments based on an ordered list of subframe timing compatibility rankings are provided in subsection 'efficiently stored subframe timing compatibility based computations'.

An example of control timing configuration assignment for a user equipment utilizing a half-duplex mode of operation is then provided in subsection 'example of half-duplex configuration assignment'. Similarly, an example of control timing configuration assignment for a user equipment utilizing a full duplex mode of operation is provided in subsection 'example of full duplex configuration assignment'. Examples of forward downlink scheduling for user equipment having full-duplex and half-duplex modes of operation are then provided under the subheading 'examples of forward downlink scheduling'.

Examples of network node configurations and example operations of such nodes are finally presented under the subheadings 'example node configuration' and 'example node operation'. It should be understood that the example node operations provide a broad description of node operations that can encompass all of the examples provided in the foregoing subheadings regardless of existing systems.

Existing system-TDD HARQ control timing

The timing of HARQ ACK/NACK (a/N) feedback for PUSCH and PDSCH and the timing of grant for PUSCH may be specified with spreading tables and process descriptions for each uplink-downlink configuration.

For TDD UL/DL (U/D) configurations 1-6 and normal HARQ operation, the user equipment should adjust the corresponding PUSCH transmission in subframe n + k according to the PDCCH and PHICH information when PDCCH and/or PHICH transmission with uplink DCI format for the user equipment is detected in subframe n, where k is given in table 1.

TABLE 1 PUSCH grant timing k for TDD configurations 0-6

For TDD U/D configuration 0 and normal HARQ operation, when PDCCH and/or PHICH transmission with uplink DCI format for a user equipment is detected in subframe n, if the Most Significant Bit (MSB) of the UL index in PDCCH with uplink DCI format is set to 1 or compared with I in subframe n =0 or 5_PHICHThe user equipment should adjust the corresponding PUSCH transmission in subframe n + k, where k is given in table 1, if PHICH is received in the corresponding resource of 1. If for TDD U/D configuration 0 and normal HARQ operation, the Least Significant Bit (LSB) of the UL index in DCI format 0/4 in subframe n is set to 1 or is set to I in subframe n =0 or 5_PHICHInformation corresponding to 1The PHICH is received in the source or in subframe n =0 or 6, the user equipment should adjust the corresponding PUSCH transmission in subframe n + 7. If both MSB and LSB of UL index in PDCCH with uplink DCI format in subframe n are transmitted for TDDU/D configuration 0, the user equipment should adjust the corresponding PUSCH transmission in both subframes n + k and n +7, where k is given in table 1.

For PUSCH transmissions scheduled from serving cell c in subframe n, the user equipment should determine that in subframe n + k_PHICHCorresponding PHICH resource of serving cell c, where k for TDD is given in Table 2 provided below_PHICH. For subframe bundling operations, the corresponding PHICH resource is associated with the last subframe in the bundle.

TABLE 2 k for TDD_PHICH

The user equipment should also feed back PDSCH decoding a/N information in the predefined UL subframe. If there is a PDSCH transmission indicated by detection of the corresponding PDCCH or a PDCCH indicating a downlink SPS release within subframe N-K, the user equipment should transmit such HARQ a/N response on the PUCCH in the UL subframe, where K is the association set K = { K } listed in table 3 provided below₀,k₁,...k_M-1In.

TABLE 3 Downlink association set index K for TDD: { K₀,k₁,...k_M-1}

In LTE Rel-10, all HARQ control timings are determined based on the primary cell (Pcell) configuration number as discussed above. The determination of HARQ operation in LTE Rel-10 only works if all aggregated TDD cells have the same U/D configuration. However, in developing the example embodiments presented herein, it has been found that directly extending this operation for aggregating different U/D configurations proves difficult.

Consider the example of PDSCHA/N feedback timing shown in fig. 10 for aggregating configuration 1 cells and configuration 2 cells. In fig. 10, U represents an uplink subframe, D represents a downlink subframe, and S represents a special subframe that can be used for both uplink and downlink. It should be understood that for simplicity, the S subframe will be considered a downlink subframe in the examples provided herein.

If the configuration 2 cell is the Pcell, a/N feedback of the configuration 1 secondary cell (Scell) PDSCH may be fed back based on timing rules of the Pcell. However, if the configuration 1 cell is Pcell, there will be no a/N feedback timing rules for subframes 3 and 8 in configuration 2 Scell.

Consider the PUSCH grant and a/N feedback timing example shown in fig. 11 for aggregating configuration 1 and configuration 2 cells. If the configuration 1 cell is a Pcell, the PUSCH grant and a/N feedback for the configuration 2Scell may be fed back based on timing rules of the Pcell. However, if the configuration 2 cell is Pcell, PUSCH cannot be scheduled for subframes 3 and 8 in configuration 1Scell, since there is no such UL grant timing in configuration 2. Note that the a/N feedback timing rules for these two subframes are also not available.

The control timing problem may be even more severe than the examples discussed above. In the case of aggregation configuration 1 and configuration 3 cells, HARQ control timing does not work regardless of which configuration is Pcell.

More specifically, consider the PDSCH a/N feedback timing shown in fig. 12:

PDSCH a/N for subframes 7 and 8 configuring 3Scell cannot be fed back if configuration 1 is Pcell.

PDSCHA/N of subframe 4 of configuration 1Scell cannot be fed back if configuration 3 is Pcell.

In addition, consider the PUSCH grant and a/N feedback timing shown in fig. 13:

PUSCH of subframe 4 in configuration 3Scell cannot be scheduled if configuration 1 is Pcell.

PUSCH of subframes 7 and 8 in configuration 1Scell cannot be scheduled if configuration 3 is Pcell.

Problems with existing systems

The following are examples of some of the problems of existing solutions that have been recognized when developing the embodiments presented herein. In Rel-10, carrier aggregation of TDD cells is specified with the restriction that the U/D configuration of all aggregated cells is the same. The need to allow more flexible carrier aggregation for TDD cells will be addressed in Rel-11 of LTE.

As discussed above, the U/D configurations of neighboring cells need to be compatible to avoid serious interference problems. There are however cases where the neighbor cells are operated by different operators or different wireless systems. LTE TDD cells adjacent to those neighbor systems are therefore required to adopt certain compatible U/D configurations. As a result, an operator may have several TDD cells with different U/D configurations on different frequencies, as shown in fig. 14.

A further complication from such an aggregation scenario is that nominally TDD user equipment may be required to transmit and receive simultaneously in certain subframes (such as subframes 7 and 8 in fig. 14). Such FDD-like operation is not compatible with existing designs of TDD user equipment. Implementing such full duplex operation in Rel-11 may result in additional user equipment complexity and cost. It is therefore necessary to also take into account possible half-duplex operation during such colliding subframes. That is, the user equipment should be instructed to perform reception or transmission during such a collision subframe, but not both.

To circumvent problems such as those identified above, the addition of additional HARQ control timing rules based on a particular aggregation scenario may be performed. In addition to the existing timing rules for seven TDD configurations, an additional set of rules may be added to specify HARQ behavior for each possible heterogeneous configuration pair. On top of these, additional specifications for the aggregation of three different U/D configurations can also be introduced. Clearly, specifying these additional rules for supporting aggregation of different U/D configurations would greatly increase LTE complexity and implementation cost.

Subframe timing compatibility

To implement a systematic solution for multiple aggregation scenarios with different TDD U/D configurations, subframe timing compatibility is designed and illustrated in fig. 15, according to some of the example embodiments. Sub-frame timing compatibility is a hierarchy that may be encoded as a look-up table, a linked list, or a plurality of numerical representations suitable for storage in a communication device.

The subframe timing compatibility ranking can be designed with the following principle:

(1) the UL subframes in a TDD configuration are also UL subframes in those TDD configurations that can be corrected with an up arrow.

E.g., subframes 2 and 3 are UL subframes in configuration 4. These two subframes are also UL in configurations 3, 1,6 and 0, and these configurations 3, 1,6 and 0 may all be connected with an up arrow from configuration 4. As a second example, subframes 2 and 7 are UL subframes in configuration 2. These two subframes are not both UL in configuration 3, since there is no up arrow connecting the two configurations.

(2) The DL subframes in the TDD configuration are also DL subframes in those TDD configurations that can be corrected with a down arrow.

E.g., subframes 0, 1, 5, 6, and 9 are DL subframes in configuration 6. These five subframes are also DL in configurations 1,2, 3,4 and 5, which may all be connected with a down arrow from configuration 6. As a second example, subframe 7 is a DL subframe in configuration 3, but not a DL subframe in configuration 2, because there is no downward arrow connecting the two configurations.

With these design properties, the subframe timing compatibility ranking may provide the following utility:

(1) given a set of TDD configurations to be aggregated, TDD configurations that can be connected from all given TDD configurations with an up arrow have the following two properties:

the TDD configuration includes UL subframes, which are a superset of all UL subframes from all given TDD configurations.

The TDD configuration includes DL subframes that are available in all given TDD configurations.

Example 1

Given TDD configurations 1 and 2, all subframes that are UL in configuration 1 or 2 are also UL subframes in configurations 1,6, and 0. The DL subframe in configuration 1,6 or 0 is also a DL subframe in configurations 1 and 2.

Given TDD configurations 1 and 3, all subframes that are UL in configuration 1 or 3 are also UL in configurations 6 and 0. The DL subframe in configuration 6 or 0 is also a DL subframe in configurations 1,2, 3,4,5, and 6.

Given TDD configurations 2, 3, and 4, all subframes that are UL in any of the three configurations are also UL in configurations 6 and 0. The DL subframe in configuration 6 or 0 is also a DL subframe in configurations 1,2, 3,4,5, and 6.

Given a set of TDD configurations, TDD configurations that can be connected from all given TDD configurations with a down arrow have the following two properties:

the TDD configuration includes DL subframes, which are a superset of all DL subframes from all given TDD configurations.

The TDD configuration includes UL subframes that are available in all given TDD configurations.

Example two

Given TDD configurations 1 and 2, all subframes that are DL in configuration 1 or 2 are also DL in configurations 2 and 5. The UL subframe in configuration 2 or 5 is also a UL subframe in configurations 1,2, 6, and 0.

Given TDD configurations 1 and 3, all subframes that are DL in configuration 1 or 3 are also DL in configurations 4 and 5. The UL subframe in configuration 4 or 5 is also a UL subframe in configurations 0, 3,4, and 6.

Given TDD configurations 2, 3, and 4, all subframes that are DL in any of the three configurations are also DL in configuration 5. The UL subframe in configuration 5 is also a UL subframe in configurations 0, 1,2, 3,4, and 6.

Configuration assignment

In Rel-8TDD, the following two subframe timing sets are set based on the same parameter, which is the serving cell U/D configuration number: (1) UL HARQ control and grant subframe timing and (2) DL HARQ a/N subframe timing. In Rel-10TOD CA, two types of subframe timing across all cells are set based on the same parameter, which is the pcell u/D configuration number.

To support carrier aggregation of TDD cells with different U/D configurations, the user equipment may be configured with the following two numbers according to the teachings of the example embodiments: (1) a UL control timing configuration number for setting UL HARQ and grant timing across all aggregated cells; and (2) a DL HARQ control timing configuration number for setting DL HARQ timing across all aggregated cells.

The UL control timing configuration number may be set to a configuration number of a configuration that can be connected with an up arrow from all aggregated configurations in the subframe timing compatibility hierarchy in fig. 15. If more than one configuration number is selectable, the selected setting may be the configuration at the lowest level in the subframe timing compatibility hierarchy. The selected setting may result in more DL subframes for PUSCH grants and a/N feedback. The following example scenarios are provided below to illustrate some of the example embodiments.

Example case 1:

if cells with configurations 1 and 2 are aggregated, the UL control timing configuration number may be set to 1,6, or 0. The selected setting may be 1.

Example case 2:

if cells with configurations 1 and 3 are aggregated, the UL control timing configuration number may be set to 6 or 0. The selected setting may be 6, which is different from the U/D configuration numbers of the two TDD cells.

This UL control timing configuration number setting guarantees the same PUSCH grant and PHICH timing across all CCs and DL subframes are available at these timings regardless of Pcell configuration. That is, the PUSCH grant and PHICH subframe are never in subframes with conflicting U/D directions across different CCs. This setup further ensures that all UL subframes from all aggregated CCs can be scheduled in or across CCs.

The DL HARQ control timing configuration number may be set to a configured configuration number, which may be connected with a down arrow from all aggregated configurations in the subframe timing compatibility hierarchy in fig. 15. If more than one configuration number is selectable, the selected setting may be a setting of the configuration at the highest level in the subframe timing compatibility hierarchy. The selected setting may result in more UL subframes for PDSCH a/N feedback. The following example scenarios are provided below to illustrate some of the example embodiments.

Example case 1:

if cells with configurations 1 and 2 are aggregated, the DL HARQ control timing configuration number may be set to 2 or 5. The selected setting may be 2.

Example case 2:

if cells with configurations 1 and 3 are aggregated, the DL HARQ control timing configuration number may be set to 4 or 5. The selected setting may be 4, which is different from the U/D configuration numbers of the two TDD cells.

This DL HARQ control timing configuration number setting guarantees the same PDSCH a/N feedback timing across all CCs and UL subframes are available at these timings regardless of Pcell configuration.

Example Carrier aggregation to configure 1 and 2TDD cells

To support aggregation of configuration 1 and 2TDD cells, two HARQ control timing configuration numbers may be set as follows:

the UL control timing configuration number may be set to 1.

The DL HARQ control timing configuration number may be set to 2.

Note that these configuration number settings apply regardless of which of the two TDD cells is used as the Pcell.

The aggregated PUSCH grant and a/N feedback timing for configuration 1 cells as Pcell and configuration 2 cells as Scell are illustrated in fig. 16. The aggregated PUSCH grant and a/N feedback timing for configuration 2 cells as Pcell and configuration 1 cells as Scell are illustrated in fig. 17. This analysis shows that all UL subframes can be scheduled from the Pcell (if cross-carrier scheduling is configured) or from the Scell itself (if cross-carrier scheduling is not configured). In addition, the a/N feedback timing for all UL subframes is clearly assigned.

PDSCHA/N feedback timing for aggregation of configuration 1 cell and configuration 2 cell is shown in fig. 18. This analysis confirms that the a/N feedback for all PDSCH in both Pcell and Scell is clearly assigned to the appropriate UL subframe on Pcell.

Example Carrier aggregation to configure 1 and 3TDD cells

To support aggregation of configuration 1 and 3TDD cells, two HARQ control timing configuration numbers may be set as follows:

the UL control timing configuration number may be set to 6.

The DL HARQ control timing configuration number may be set to 4.

Note that these configuration number settings apply regardless of which of the two TDD cells is used as the Pcell.

The aggregated PUSCH grant and a/N feedback timing (i.e., for uplink a/N feedback timing) for configuration 1 cells as Pcell and configuration 3 cells as Scell is illustrated in fig. 19. The aggregated PUSCH grant and a/N feedback timing for configuration 3 cells as Pcell and configuration 1 cells as Scell are illustrated in fig. 20. This analysis shows that all UL subframes can be scheduled from the Pcell (if cross-carrier scheduling is configured) or from the Scell itself (if cross-carrier scheduling is not configured). In addition, the a/N feedback timing for all UL subframes is clearly assigned.

PDSCHA/N feedback timing for aggregation of configuration 1 cell and configuration 3 cell is shown in fig. 21. This analysis confirms that the a/N feedback for all PDSCH in both Pcell and Scell is clearly assigned to the appropriate UL subframe on Pcell.

Computing subframe timing compatibility based on efficient storage

As should be understood from the above, according to some of the example embodiments, the UL control and DL HARQ control timing configuration numbers may be set based on systematic rules, e.g., encoded in the subframe timing compatibility hierarchy as shown in fig. 15, for a given set of aggregated TDD cells with different U/D configurations. The UL control and DL HARQ control timing configuration numbers thus selected may be different from any of the U/D configuration numbers of the aggregated cells.

The UL control timing configuration number may be set to a configuration number of a configuration that can be connected with an upward arrow from all aggregated configurations in the subframe timing compatibility hierarchy in fig. 15. If more than one configuration number is selectable, the setting may be selected to the configuration at the lowest level in the subframe compatibility hierarchy. This setup generates more DL subframes for PUSCH grant and a/N feedback.

The DL HARQ control timing configuration number may be set to a configuration number of a configuration that can be connected with a downward arrow from all aggregated configurations in the subframe timing compatibility hierarchy in fig. 15. If more than one configuration number is selectable, the setting may be selected to be the configuration at the highest level in the subframe timing compatibility hierarchy. This setting results in more UL subframes for PDSCH a/N feedback.

Some of the example embodiments may also be directed to an efficient digital representation and storage method of sub-frame timing compatibility rankings. Some of the example embodiments may also be directed to an efficient calculation method and corresponding apparatus for calculating UL control timing configuration numbers and DL HARQ control timing configuration numbers.

According to some of the example embodiments, the subframe timing compatibility ranking may be represented by a set table. The UL control timing configuration number and the DL HARQ control timing configuration number may be calculated using a set intersection operation. If there is more than one control timing configuration number candidate after the set intersection operation, the network node may select a preferred control timing configuration number setting based at least on the system load and user equipment application needs.

A UL control timing configuration candidate set and a DL HARQ control timing configuration candidate set may be stored for each of the LTE cell U/D configurations. Examples of specific values of the candidate set are shown in the tables provided below.

Table 4 control timing configuration set

According to some of the example embodiments, for a given set of cell U/D configurations to be aggregated, the UL control timing configuration number may be set to a configuration number from the intersection of all UL control timing configuration candidate sets corresponding to the cell U/D configurations to be aggregated. The following example scenarios are provided below to illustrate some of the example embodiments.

Example case 1:

if cells with configurations 1 and 2 are aggregated, the corresponding UL control timing configuration candidate sets may be {1,6,0} and {2,1,6,0 }. The intersection of all these sets can be computed as 1,6, 0. Thus, the UL control timing configuration number may be set to 1,6, or 0.

Example case 2:

if cells with configurations 1 and 3 are aggregated, the corresponding UL control timing configuration candidate sets may be {1,6,0} and {3,6,0 }. The intersection of all these sets can be computed as 6, 0. Therefore, the UL control timing configuration number may be set to 6 or 0.

Example case 3:

if cells with configurations 1,3, and 4 are aggregated, the corresponding UL control timing configuration candidate set may be {1,6,0}, {3,6,0}, and {4,1,3,6,0 }. The intersection of all these sets can be computed as 6, 0. Therefore, the UL control timing configuration number may be set to 6 or 0.

According to some of the example embodiments, for a given set of cell U/D configurations to be aggregated, the DL HARQ control timing configuration number may be set to a configuration number from the intersection of all DL HARQ control timing configuration candidate sets corresponding to the cell U/D configurations to be aggregated. The following example scenarios are provided below to illustrate some of the example embodiments.

Example case 1:

if cells with configurations 1 and 2 are aggregated, the corresponding DL HARQ control timing configuration candidate set may be {1,2,4,5} and {2,5 }. The intersection of all these sets can be computed as 2, 5. Therefore, the DL HARQ control timing configuration number may be set to 2 or 5.

Example case 2:

if cells with configurations 1 and 3 are aggregated, the corresponding DL HARQ control timing configuration candidate set may be {1,2,4,5} and {3,4,5 }. The intersection of all these sets can be computed as 4, 5. Therefore, the DL HARQ control timing configuration number may be set to 4 or 5.

Example case 3:

if cells with configurations 1,3 and 4 are aggregated, the corresponding DL HARQ control timing configuration candidate set may be {1,2,4,5}, {3,4,5} and {4,5 }. The intersection of all these sets can be computed as 4, 5. Therefore, the DL HARQ control timing configuration number may be set to 4 or 5.

If there is more than one control timing configuration number candidate after the set intersection operation, the network node or the user equipment may select and signal a preferred control timing configuration number setting based at least on the system load and user equipment application needs. The signaling of control timing may be accomplished, for example, with Radio Resource Control (RRC) signaling.

It should also be appreciated that the subframe timing compatibility ranking may be represented by an ordered set table, according to some of the example embodiments. The UL control timing configuration number and the DL HARQ control timing configuration number may be calculated with a set intersection operation while preserving the number order within the set. The selected control timing configuration number may be the first or last number after the set intersection operation.

A UL control timing configuration candidate set and a DL HARQ control timing configuration candidate set may be stored for each of the LTE cell U/D configurations. Specific values of the candidate or ordered set are shown in table 4. The order of the candidate configuration numbers of each of the candidate sets shown in the table may be preserved in storage.

For a given set of cell U/D configurations to be aggregated, the UL control timing configuration number may be set to the configuration number from the intersection of all UL control timing configuration candidate sets corresponding to the cell U/D configurations to be aggregated, where the set intersection operation preserves the numbering ordering in the set concerned. The following example scenarios are provided below to illustrate some of the example embodiments.

Example case 1:

if cells with configurations 1 and 2 are aggregated, the corresponding UL control timing configuration candidates or ordered sets may be {1,6,0} and {2,1,6,0 }. The intersection of all these sets can be computed as 1,6, 0. Therefore, the selected UL control timing configuration number may be 1.

Example case 2:

if cells with configurations 1 and 3 are aggregated, the corresponding UL control timing configuration candidates or ordered sets may be {1,6,0} and {3,6,0 }. The intersection of all these sets can be computed as 6, 0. Therefore, the selected UL control timing configuration number may be 6.

Example case 3:

if cells with configurations 1,3, and 4 are aggregated, the corresponding UL control timing configuration candidates or ordered sets may be {1,6,0}, {3,6,0}, and {4,1,3,6,0 }. The intersection of all these sets can be computed as 6, 0. Therefore, the selected UL control timing configuration number may be 6.

For a given set of cell U/D configurations to be aggregated, the DL HARQ control timing configuration number may be set to the configuration number from the intersection of all DL HARQ control timing configuration candidate sets corresponding to the cell U/D configurations to be aggregated, where the set intersection operation preserves the numbering ordering in the set concerned. The following example scenarios are provided below to illustrate some of the example embodiments.

Example case 1:

if cells with configurations 1 and 2 are aggregated, the corresponding DL HARQ control timing configuration candidates or ordered sets may be {1,2,4,5} and {2,5 }. The intersection of all these sets can be computed as 2, 5. Therefore, the selected DL HARQ control timing configuration number may be 2.

Example case 2:

if cells with configurations 1 and 3 are aggregated, the corresponding DL HARQ control timing configuration candidates or ordered sets may be {1,2,4,5} and {3,4,5 }. The intersection of all these sets can be computed as 4, 5. Therefore, the selected DL HARQ control timing configuration number may be 4.

Example case 3:

if cells with configurations 1,3 and 4 are aggregated, the corresponding DL HARQ control timing configuration candidates or ordered sets may be {1,2,4,5}, {3,4,5} and {4,5 }. The intersection of all these sets can be computed as 4, 5. Therefore, the selected DL HARQ control timing configuration number may be 4.

Examples of half-duplex configuration assignments

A user equipment capable of half-duplex operation only may perform transmission or reception in a subframe instead of two actions. Therefore, according to some of the example embodiments, a subframe in a collision-free U/D direction may be scheduled with a PDCCH transmitted within the same subframe time (intra-subframe scheduling).

For subframes with conflicting U/D directions across CCs, half-duplex user equipment needs to be informed in advance of the scheduled direction. Forward subframe UL scheduling has been used in LTE. However, additional forward subframe DL scheduling PDCCH may be required.

According to an example embodiment, the following features are designed for forward subframe DL scheduling PDCCH:

if cross-CC scheduling is not configured, additional forward subframe DL scheduling PDCCH for individual cells (referred to as intra-CC forward subframe DL scheduling PDCCH) may be added.

If cross-CC scheduling is configured, additional cross-CC forward subframe DL scheduling PDCCH from Pcell may be added.

The forward scheduling timing may be based on the UL grant timing of the same target cell. Other forward scheduling timing methods may also be used.

Forward subframe DL scheduling PDCCH can be implemented according to the flexible carrier indicator teaching.

Example Carrier aggregation to configure 1 and 2TDD cells

To support aggregation of configuration 1 and 2TDD cells, two HARQ control timing configuration numbers may be set as follows:

the UL control timing configuration number may be set to 1.

The DL HARQ control timing configuration number may be set to 2.

For subframes with conflicting U/D directions across CCs, the half-duplex user equipment needs to be informed of the scheduled direction in advance. An additional forward subframe DL scheduling PDDCH based on UL grant timing can be introduced as follows:

if configuration 1 is Pcell and cross-CC scheduling is configured, two additional cross-CC forward subframe DL scheduling PDCCHs (from configuration 1 cells) are shown in fig. 22.

Two additional intra-CC forward subframe DL scheduling PDCCHs (from configuration 2 cells) are shown in fig. 22 if configuration 2 is Pcell or if cross-CC scheduling is not configured.

Example Carrier aggregation to configure 1 and 3TDD cells

To support aggregation of configuration 1 and 3TDD cells, two HARQ control timing configuration numbers may be set as follows:

the UL control timing configuration number may be set to 6.

The DL HARQ control timing configuration number may be set to 4.

For subframes with conflicting U/D directions across CCs, half-duplex user equipment needs to be informed in advance of the scheduled direction. An additional forward subframe DL scheduling PDDCH based on UL grant timing can be introduced as follows:

if cross-CC scheduling is not configured, three intra-CC forward subframes DL scheduling PDCCHs from Pcell and Scell may be added as shown in fig. 23.

If cross-CC scheduling is configured, three cross-CC forward subframe DL scheduling PDCCHs from the Pcell may be added as shown in FIG. 23.

Examples of full-duplex configuration assignments

A full-duplex user equipment may perform transmission and reception simultaneously in subframes with conflicting U/D directions across different CCs. According to the above teachings of example embodiments, if cross-carrier scheduling is not configured, all DL subframes may be scheduled within a CC and within a subframe.

If cross-carrier scheduling is configured, in the subframe in the collision-free direction, the DL subframe in the scheduling cell may carry a cross-carrier DL scheduling PDCCH to schedule other DL subframes at the same subframe time on other cells. In addition, in a subframe having a collision direction, if the scheduling cell is a DL subframe, a PDCCH may be transmitted from the subframe to schedule other DL subframes of the same subframe time on other cells. Further, in a subframe having a collision direction, if a scheduling cell is a UL subframe, a PDCCH cannot be transmitted from the subframe to schedule other DL subframes of the same subframe time on other cells.

Thus, cross-CC forward subframe DL scheduling of PDCCH from the scheduling cell may be enabled, according to some of the example embodiments. According to some of the example embodiments, cross-CC forward subframe DL scheduling PDCCH designed in example embodiments directed to half-duplex operation is applied to support full-duplex operation with certain cross-carrier scheduling scenarios.

Example Carrier aggregation to configure 1 and 2TDD cells

To support aggregation of configuration 1 and 2TDD cells, two HARQ control timing configuration numbers may be set as follows:

the UL control timing configuration number may be set to 1.

The DL HARQ control timing configuration number may be set to 2.

If configuration 2 is Pcell, all DL subframes may be scheduled within a subframe and within a CC or across CCs.

If configuration 1 is Pcell, all DL subframes may be scheduled within CC and within subframes if cross-CC scheduling is not configured. If cross scheduling is configured, all DL subframes in Scell may be CC scheduled in subframes other than subframes 3 and 8. Note that these two subframes are subframes with conflicting U/D directions. Thus, the half-duplex solution can be reused here. The two subframes may be scheduled with a forward subframe scheduling PDCCH based on their UL grant timing. These two additional cross-CC forward subframe DL scheduling PDCCHs are shown in fig. 24.

Example Carrier aggregation to configure 1 and 3TDD cells

To support aggregation of configuration 1 and 3TDD cells, two HARQ control timing configuration numbers may be set as follows:

the UL control timing configuration number may be set to 6.

The DL HARQ control timing configuration number may be set to 4.

If cross-CC scheduling is not configured, all DL subframes may be scheduled within a CC and within a subframe. If cross scheduling is configured, all DL subframes in Scell may be CC scheduled within a subframe except subframes 7 and 8 in configuration 3 may not be cross scheduled within a subframe if configuration 1 is Pcell. Further, if configuration 3 is Pcell, subframe 4 cannot be cross-scheduled within a subframe.

With the half-duplex solution from the example embodiment directed to half-duplex scheduling, PDCCH is scheduled using two (if Pcell for configuration 1) or one (if Pcell for configuration 3) additional cross-CC forward subframes DL based on the corresponding UL grant timing as shown in fig. 25.

Examples of forward downlink scheduling

The forward subframe DL scheduling PDCCH introduced in example embodiments directed to half and full duplex assignments is a new feature and may require implementation complexity to integrate into existing network node hardware and software architectures. It would therefore be beneficial to reduce the need to rely on such a new forward subframe DL for scheduling PDCCH.

According to some of the example embodiments, the following two operation rules may be implemented on the user equipment for subframes with conflicting directions across the aggregated CCs:

in full duplex operation, the user equipment may monitor the PDCCH when scheduling a CC with a DL direction (even if the user equipment has been previously given a grant for transmission in a CC with a UL direction).

In half-duplex operation, if the user equipment has not been previously given any grant to transmit in any CC with UL direction, the user equipment may monitor the PDCCH when scheduling CCs with DL direction.

Example node configuration

Fig. 26 illustrates an example of a base station 103, which may incorporate some of the example embodiments discussed above. As shown in fig. 26, the base station 103 may include receive 302 and transmit 304 units configured to receive and transmit, respectively, any form of communication or control signals within the network. It should be understood that the receive 302 and transmit 304 units may be included as a single transceiver unit. It should also be appreciated that the receive 302 and transmit 304 units or transceiving units may be in the form of any input/output communication port known in the art.

The base station 103 may also include at least one memory unit 308 that may be in communication with the receiving unit 302 and the transmitting unit 304. Memory unit 308 may be configured to store received or transmitted data and/or executable program instructions. The memory unit 308 may also be configured to store timing compatibility rankings and/or control timing configuration candidates or ordered sets. The memory unit 308 may be any suitable type of computer-readable memory and may be of the volatile and/or nonvolatile type.

The base station 103 further comprises a determining unit 308 configured for determining at least one timing configuration number for the plurality of aggregated cells. The base station further comprises an assignment unit 310 configured for assigning an uplink-downlink configuration to the user equipment 101.

The determination unit 308 and/or the assignment unit 310 may be any suitable type of calculation unit, such as a microprocessor, a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA), or an Application Specific Integrated Circuit (ASIC). It should be understood that the determining and/or assigning units may be included as a single unit or any number of units.

Fig. 27 illustrates an example of a user device 101, which may incorporate some of the example embodiments discussed above. As shown in fig. 27, the user equipment 101 may include a receiving 402 unit and a transmitting 404 unit configured to receive and transmit, respectively, any form of communication or control signals within the network. It should be understood that the receive 402 and transmit 404 units may be included as a single transceiver unit. It should also be appreciated that the receive 402 and transmit 404 units or transceiving units may be in the form of any input/output communication port known in the art.

User equipment 101 may also include at least one memory unit 408 that may be in communication with the receiving 402 and transmitting 404 units. Memory unit 408 may be configured to store received or transmitted data and/or executable program instructions. The memory unit 408 may also be configured for storing timing compatibility rankings and/or HARQ control timing configuration candidates or ordered sets. The memory unit 408 can be any suitable type of computer-readable memory and can be of the volatile and/or nonvolatile type.

The user equipment 101 may further comprise an implementation unit 408 configured for implementing the control timing based on the at least one timing configuration number. The user equipment 101 may also comprise a determining unit 402 configured for receiving or determining at least one timing configuration number. The implementation unit 408 and/or the determination unit 402 may be any suitable type of calculation unit, such as a microprocessor, a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA), or an Application Specific Integrated Circuit (ASIC). It should be understood that the implementing unit and the determining unit need not be provided as two separate units but may be provided as a single unit or any number of units.

Example node operation

Fig. 28 is a flow diagram depicting example operations that may be taken by the base station 103 of fig. 26. Example operation 10

The base station determines 10 at least one timing configuration number for a plurality of aggregated cells of the multi-carrier network. Each aggregated cell is associated with an uplink-downlink configuration number. At least two uplink-downlink configuration numbers of the plurality of aggregated cells are not equal. A plurality of aggregated cells are associated with a user equipment. The determination unit 308 is configured to perform the determination 10.

According to some example embodiments, the at least one timing configuration number may indicate or be used to determine a downlink HARQ control timing configuration for establishing downlink HARQ a/N timing across multiple aggregated cells. According to some of the example embodiments, the at least one timing configuration number may indicate or be used to determine an uplink control timing configuration number for establishing uplink scheduling grants and/or a/N timing across a plurality of aggregated cells.

Example operation 11

According to some of the example embodiments, determining 10 may further comprise determining 11 at least one timing configuration number based on uplink-downlink configuration numbers of the plurality of aggregated cells. The determination unit 308 is configured to perform the determination 10.

In some of the example embodiments, the at least one timing configuration number may be determined to be equal to one of said uplink-downlink configuration numbers of the plurality of aggregated cells, e.g. as shown in example case 2 under the subtitle configuration assignment. In some of the example embodiments, the at least one timing configuration number may be determined not to equal any of the uplink-downlink configuration numbers of the plurality of aggregated cells, for example as shown in example case 1 under the subtitle configuration assignment. The at least one timing configuration number may be determined such that control data is transmitted to and from the user equipment and the network in a collision-free manner.

Example operation 12

According to some of the example embodiments, determining 10 may further comprise determining 12 an uplink-downlink configuration based on the subframe timing compatibility ordering, for example as shown in fig. 15. The determination unit 308 may perform the determination 12.

Example operation 14

According to some of the example embodiments, the determining may further comprise arranging 14 the subframe timing compatibility ordering such that the uplink-downlink configuration at a higher level of ordering comprises uplink subframes which are a superset of all uplink subframes from the uplink-downlink configuration at a lower level of ordering. The determination unit may be configured to perform the arrangement 14.

Example operation 16

According to some of the example embodiments, determining 12 may further comprise arranging 16 the subframe timing compatibility ordering such that the uplink-downlink configuration at a lower level of the ordering comprises uplink subframes which are a superset of all downlink subframes from the uplink-downlink configuration at a higher level of the ordering. The determination unit may be configured to perform the arrangement 16.

Example operation 18

The base station 103 assigns 18 at least one timing configuration number to the user equipment. Assignment unit 310 is configured to perform assignment 18.

Example operation 20

According to some of the example embodiments, assignment 18 may also include assigning 20 forward subframe downlink scheduling with respect to PDCCH when there are colliding subframes, as illustrated in fig. 22-25. Assignment unit 310 can be configured to perform assignment 20.

Example operation 22

According to some of the example embodiments, as illustrated in fig. 22, 24 and 25, assignment 18 may also include assigning 22 cross component carrier forward subframe downlink scheduling with respect to PDCCH when there is a colliding subframe. Assignment unit 310 can be configured to perform assignments 22.

Example operation 24

According to some of the example embodiments, the method may further comprise regulating 24 use of the forward subframe downlink scheduling by monitoring the PDCCH in a scheduling component carrier having a downlink subframe in a full duplex mode of operation if an advance grant for transmission of a carrier component in the uplink direction has been given to the user equipment.

Example operation 26

According to some of the example embodiments, the method may also comprise regulating 26 use of forward subframe downlink scheduling by monitoring PDCCH in a scheduling component carrier having a downlink subframe in a half-duplex mode of operation if no advance grant has been given to the user equipment to transmit carrier components in the uplink direction. The assignment unit and/or the determination unit may perform the conditioning 26.

Example operation 28

According to some of the example embodiments, the method may also comprise communicating 28 the at least one timing configuration number to the user equipment via RRC signalling. The determination unit and/or the transmission unit may perform the communication 28.

Fig. 29 is a flowchart depicting example operations that may be taken by the user device 101 of fig. 27.

Example operation 30

The user equipment determines 30 at least one timing configuration number for a plurality of aggregated cells of the multi-carrier network, wherein each aggregated cell is associated with an uplink-downlink configuration number, wherein at least two uplink-downlink configuration numbers of the plurality of aggregated cells are not equal. A plurality of aggregated cells are associated with a user equipment. The determination unit 308 is configured for performing the determination 30.

According to some example embodiments, the at least one timing configuration number may indicate or be used to determine a HARQ control timing configuration for establishing downlink HARQ a/N timing across multiple aggregated cells. According to some of the example embodiments, the at least one timing configuration number may indicate or be used to determine an uplink control timing configuration number for establishing uplink scheduling grants and/or a/N timing across a plurality of aggregated cells.

Example operation 31

According to some of the example embodiments, the determining 30 may further comprise receiving 31 at least one timing configuration from the base station. It should be appreciated that the at least one timing configuration number may be received via RRC signaling. The determining unit and/or the receiving unit may be configured to perform the receiving 31.

Example operation 32

According to some of the example embodiments, determining 30 may further comprise determining 32 at least one timing configuration number such that control data is transmitted to and from the user equipment and the network in a collision-free manner. The determination unit may be configured to perform the determination 32.

Example operation 33

The user equipment 101 implements 33 the control timing based on the at least one timing configuration number. The enforcement unit 408 is configured to perform enforcement operations.

In some of the example embodiments, the at least one timing configuration number may be implemented to be equal to one of said uplink-downlink configuration numbers of the plurality of aggregated cells, e.g. as shown in example case 2 under a subheading configuration assignment. In some of the example embodiments, the at least one timing configuration number may be implemented not to equal any of the uplink-downlink configuration numbers of the plurality of aggregated cells, e.g., as shown in example case 1 under the subtitle configuration assignment.

Example operation 34

According to some of the example embodiments, the implementation 33 may further include scheduling 34 a forward subframe downlink with respect to the PDCCH when there is a colliding subframe. The enforcement unit 408 may be configured to execute the schedule 34.

Example operation 36

According to some of the example embodiments, implementation 33 may further include scheduling 36 a cross component carrier forward subframe downlink with respect to PDCCH when there is a colliding subframe. Enforcement unit 408 may be configured to execute schedule 36.

Example operation 37

According to some of the example embodiments, the implementation 33 may further comprise scheduling 37 the control data based on the at least one timing configuration such that the control data is transmitted to and from the user equipment and the network in a collision-free manner.

Conclusion

The description of the example embodiments provided herein has been presented for purposes of illustration. The description is not intended to be exhaustive or to limit example embodiments to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of various alternatives to the embodiments provided. The examples discussed herein were chosen and described in order to explain the principles and the nature of various example embodiments and their practical application to enable one skilled in the art to utilize the example embodiments in various ways and with various modifications as are suited to the particular use contemplated. The features of the embodiments described herein may be combined in all possible combinations of methods, apparatus, modules, systems, and computer program products. It should be understood that the example embodiments presented herein may be implemented in any combination with each other.

It should be noted that the word "comprising" does not necessarily exclude the presence of other elements or steps than those listed and the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. It should also be noted that any reference signs do not limit the scope of the claims, that the exemplary embodiments may be implemented at least partly by means of both hardware and software, and that the same item of hardware may represent several "means", "units" or "devices".

"device" as that term is used herein is to be broadly interpreted to include a radiotelephone having the ability to be used for internet/intranet access, a web browser, an organizer, a calendar, a camera (e.g., a video and/or still image camera), a sound recorder (e.g., a microphone), and/or a Global Positioning System (GPS) receiver; personal Communications System (PCS) user equipment that may combine a cellular radiotelephone with data processing; a Personal Digital Assistant (PDA) which may comprise a radiotelephone or a wireless communication system; a laptop computer; cameras with communication capabilities (e.g., video and/or still image cameras); and any other computing or communication device capable of transceiving, such as a personal computer, home entertainment system, television, and the like.

Although the description is mainly given for user equipment as a measurement or recording unit, the skilled person will understand that "user equipment" is a non-limiting term meaning any wireless device, terminal or node (e.g. PDA, laptop, mobile station, sensor, fixed relay, mobile relay or even radio base station, e.g. femto base station) capable of receiving in the DL and transmitting in the UL.

A cell is associated with a radio node, wherein a radio node or radio network node or eNodeB, which are used interchangeably in the description of example embodiments, includes in a general sense any node that transmits radio signals for measurements, e.g. an eNodeB, a macro/micro/pico base station, a home eNodeB, a relay, a beacon device or a repeater. A radio node herein may comprise a radio node operating in one or more frequencies or frequency bands. It may be a CA capable radio node. It may also be a single RAT or a multi-RAT node. The multi-RAT nodes may include nodes with co-located RATs or nodes supporting multi-standard radio (MSR) or hybrid radio nodes.

Various example embodiments described herein are described in the general context of method steps or processes, which may be implemented in one aspect by a computer program product, embodied in a computer-readable medium, including computer-executable instructions, such as program code, executed by computers in networked environments. Computer-readable media can include removable and non-removable memory devices including, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), Compact Disks (CDs), Digital Versatile Disks (DVDs), and the like. Generally, program modules may include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of program code for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps or processes.

In the drawings and specification, there have been disclosed example embodiments. Many variations and modifications may be made to these embodiments. Therefore, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the embodiments being defined by the following claims.

Claims (48)

1. A method in a base station (103) for configuring control timing to and from a user equipment (101) in a multi-cell communication network, the method comprising:

determining (10) at least one timing configuration number for a plurality of aggregated cells of the multi-cell communication network, each aggregated cell being associated with an uplink-downlink configuration number, wherein at least two uplink-downlink configuration numbers of the plurality of aggregated cells are not equal and the plurality of aggregated cells are associated with the user equipment (101); and

assigning (18) the at least one timing configuration number to the user equipment (101).

2. The method of claim 1, wherein the at least one timing configuration number indicates a downlink hybrid automatic repeat request, HARQ, control timing configuration for establishing downlink HARQ a/N timing across the plurality of aggregated cells.

3. The method according to any of claims 1-2, wherein the at least one timing configuration number indicates an uplink control timing configuration number used for establishing uplink scheduling grant timing across the plurality of aggregated cells, and/or positive acknowledgement/negative acknowledgement, a/N, timing.

4. The method according to any of claims 1-3, wherein the at least one timing configuration number is equal to one of the uplink-downlink configuration numbers of the plurality of aggregated cells.

5. The method according to any of claims 1-3, wherein the at least one timing configuration number is not equal to any of the uplink-downlink configuration numbers of the plurality of aggregated cells.

6. The method according to any of claims 1-5, wherein the at least one timing configuration number is determined such that control data is transmitted to and from the user equipment and the network in a collision-free manner.

7. The method according to any of claims 1-6, wherein the determining (10) further comprises determining (11) the at least one timing configuration number based on the uplink-downlink configuration numbers of the plurality of aggregated cells.

8. The method of claim 7, wherein the determining (10) further comprises determining (12) the at least one timing configuration number based on a subframe timing compatibility ordering.

9. The method of claim 8, wherein the determining (12) further comprises arranging (14) the subframe timing compatibility ordering such that an uplink-downlink configuration at a higher level of the ordering comprises an uplink subframe that is a superset of all uplink subframes from an uplink-downlink configuration at a lower level of the ordering.

10. The method according to any of claims 8-9, wherein the determining (12) further comprises arranging (16) the subframe timing compatibility ordering such that an uplink-downlink configuration on a lower level of the ordering comprises a downlink subframe that is a superset of all downlink subframes from an uplink-downlink configuration on a higher level of the ordering.

11. The method according to any of claims 1-10, wherein the assigning (18) further comprises communicating the at least one timing configuration number to the user equipment via radio resource control, RRC, signaling.

12. The method according to any of claims 1-11, wherein the assigning (18) further comprises, when there is a colliding subframe, assigning (20) a forward subframe downlink scheduling timing in relation to a physical downlink control channel, PDCCH.

13. The method according to any of claims 1-12, wherein the assigning (18) further comprises, when there is a colliding subframe, assigning (22) a cross component carrier forward subframe downlink scheduling timing in relation to a physical downlink control channel, PDCCH.

14. A base station (103) for configuring control timing to and from a user equipment (101) in a multi-cell communication network, the base station comprising:

a determining unit (308) configured for determining at least one timing configuration number for a plurality of aggregated cells of the multi-cell communication network, each aggregated cell being associated with an uplink-downlink configuration number, wherein at least two uplink-downlink configuration numbers of the plurality of aggregated cells are not equal and the plurality of aggregated cells are associated with the user equipment (101); and

an assigning unit (310) configured for assigning the at least one timing configuration number to the user equipment (101).

15. The base station of claim 14, wherein the at least one timing configuration number indicates a downlink hybrid automatic repeat request, HARQ, control timing configuration for establishing downlink HARQ a/N timing across the plurality of aggregated cells.

16. The base station according to any of claims 14-15, wherein the at least one timing configuration number indicates an uplink control timing configuration number for establishing uplink scheduling grant timing across the plurality of aggregated cells, and/or positive acknowledgement/negative acknowledgement, a/N, timing.

17. The base station according to any of claims 14-16, wherein the at least one timing configuration number is equal to one of the uplink-downlink configuration numbers of the plurality of aggregated cells.

18. The base station according to any of claims 14-16, wherein the at least one timing configuration number is not equal to any of the uplink-downlink configuration numbers of the plurality of aggregated cells.

19. The base station according to any of claims 14-18, wherein the at least one timing configuration number is determined such that control data is transmitted to and from the user equipment and the network in a collision-free manner.

20. The base station according to any of claims 14-19, wherein the determining unit (308) is further configured for determining the at least one timing configuration number based on the uplink-downlink configuration numbers of the plurality of aggregated cells.

21. The base station according to claim 20, wherein the determining unit (308) is further configured for determining the at least one timing configuration number based on a subframe timing compatibility ordering.

22. The base station of claim 20 wherein the subframe timing compatibility ordering is arranged such that an uplink-downlink configuration at a higher level of the ordering comprises an uplink subframe that is a superset of all uplink subframes from an uplink-downlink configuration at a lower level of the ordering.

23. The base station according to any of claims 21-22, wherein the subframe timing compatibility ordering is arranged such that an uplink-downlink configuration at a lower level of the ordering comprises a downlink subframe that is a superset of all downlink subframes from an uplink-downlink configuration at a higher level of the ordering.

24. The base station according to any of claims 14-23, wherein the assigning unit (310) is further configured for communicating the at least one timing configuration number to the user equipment via radio resource control, RRC, signaling.

25. The base station according to any of claims 14-24, wherein the assigning unit (310) is further configured to assign a forward subframe downlink scheduling timing in relation to a physical downlink control channel, PDCCH, when there is a colliding subframe.

26. The base station according to any of claims 14-25, wherein the assigning unit (310) is further configured to assign a cross component carrier forward subframe downlink scheduling timing in relation to a physical downlink control channel, PDCCH, when there is a colliding subframe.

27. A method in a user equipment (101) for configuring control timing for the user equipment (101) in a multi-cell communication network, the method comprising:

determining (30) at least one timing configuration number for a plurality of aggregated cells of the multi-cell communication network, each aggregated cell being associated with an uplink-downlink configuration number, wherein at least two uplink-downlink configuration numbers of the plurality of aggregated cells are not equal and the plurality of aggregated cells are associated with the user equipment (101); and

-implementing (33) control timing based on the at least one timing configuration number.

28. The method as in claim 27, wherein the at least one timing configuration number indicates a downlink hybrid automatic repeat request, HARQ, control timing configuration for establishing downlink HARQ a/N timing across the plurality of aggregated cells.

29. The method according to any of claims 27-28, wherein the at least one timing configuration number indicates an uplink control timing configuration number used for establishing uplink scheduling grant timing across the plurality of aggregated cells, and/or positive acknowledgement/negative a/N timing.

30. The method according to any of claims 27-29, wherein the at least one timing configuration number is equal to one of the uplink-downlink configuration numbers of the plurality of aggregated cells.

31. The method according to any of claims 27-29, wherein the at least one timing configuration number is not equal to any of the uplink-downlink configuration numbers of the plurality of aggregated cells.

32. The method according to any of claims 27-31, wherein the implementing (33) further comprises scheduling (37) control data based on the at least one timing configuration number such that the control data is transmitted to and from the user equipment and the network in a collision-free manner.

33. The method according to any of claims 27-32, wherein the determining (30) further comprises receiving (31) the at least one timing configuration from a base station (103).

34. The method of claim 33, wherein the at least one timing configuration is received via radio resource control, RRC, signaling.

35. The method according to any of claims 27-34, wherein the determining (30) further comprises determining (32) the at least one timing configuration number such that control data is transmitted to and from the user equipment and the network in a collision-free manner.

36. The method according to any of claims 27-35, wherein the implementing (33) further comprises, when there is a colliding subframe, scheduling (34) a forward subframe downlink scheduling timing in relation to a physical downlink control channel, PDCCH.

37. The method of any of claims 27-36, wherein the implementing (33) further comprises, when there is a colliding subframe, scheduling (36) a cross component carrier forward subframe downlink scheduling timing with respect to a physical downlink control channel, PDCCH.

38. A user equipment (101) for configuring control timing for a user equipment in a multi-cell communication network, the user equipment comprising:

a determining unit (402) configured for determining at least one timing configuration number for a plurality of aggregated cells of the multi-cell communication network, each aggregated cell being associated with an uplink-downlink configuration number, wherein at least two uplink-downlink configuration numbers of the plurality of aggregated cells are not equal and the plurality of aggregated cells are associated with the user equipment (101); and

an implementation unit (408) configured for implementing control timing based on the at least one timing configuration number.

39. The user equipment of claim 38, wherein the at least one timing configuration number indicates a downlink hybrid automatic repeat request, HARQ, control timing configuration for establishing downlink HARQ a/N timing across the plurality of aggregated cells.

40. The user equipment according to any of claims 38-39, wherein the at least one timing configuration number indicates an uplink control timing configuration number used for establishing uplink scheduling grant timing across the plurality of aggregated cells, and/or positive acknowledgement/negative acknowledgement (A/N) timing.

41. The user equipment according to any of claims 38-40, wherein the at least one timing configuration number is equal to one of the uplink-downlink configuration numbers of the plurality of aggregated cells.

42. The user equipment of any of claims 38-40, wherein the at least one timing configuration number is not equal to any of the uplink-downlink configuration numbers of the plurality of aggregated cells.

43. The user equipment according to any of claims 38-42, wherein the enforcing unit (408) is further configured to schedule control data based on the at least one timing configuration number such that control data is transmitted to and from the user equipment and the network in a collision-free manner.

44. The user equipment according to any of claims 38-43, wherein the determining unit (402) is further configured for receiving the at least one timing configuration number from the base station (103).

45. The user equipment of claim 44, wherein the at least one timing configuration number is received via Radio Resource Control (RRC) signaling.

46. The user equipment according to any of claims 38-45, wherein the enforcing unit (408) is configured to enforce the at least one timing configuration number such that control data is transmitted to and from the user equipment and the network in a collision-free manner.

47. The user equipment according to any of claims 38-46, wherein the enforcing unit (408) is further configured to schedule a forward subframe downlink scheduling timing in relation to a physical downlink control channel, PDCCH, when there are colliding subframes.

48. The user equipment according to any of claims 38-47, wherein the enforcing unit (408) is further configured for scheduling cross component carrier forward subframe downlink scheduling timing with respect to a physical downlink control channel, PDCCH, when there is a colliding subframe.