HK1167553B - Method and apparatus for handling inconsistent control information in a wireless communication system - Google Patents

Description

Method and apparatus for processing inconsistent control information in wireless communication system

The present application claims priority from united states provisional application 61/160,926 entitled "METHOD and APPARATUS FOR linking information IN LTE" and united states provisional application 61/160,996 entitled "METHOD and APPARATUS FOR linking information IN LTE", filed on day 3, month 17 of 2009, both of which are incorporated herein by reference.

Technical Field

The present disclosure relates to communication, and more particularly, to techniques for communicating in a wireless communication system.

Background

Wireless communication systems are widely deployed to provide various communication content such as voice, video, packet data, messaging, broadcast, and so on. These wireless systems may be multiple-access systems capable of supporting multiple users by sharing the available system resources. Examples of such multiple-access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal FDMA (OFDMA) systems, and single carrier FDMA (SC-FDMA) systems.

A wireless communication system may include multiple base stations capable of supporting communication for multiple User Equipments (UEs). A UE may communicate with a base station via the downlink and uplink. The downlink (or forward link) refers to the communication link from the base stations to the UEs, and the uplink (or reverse link) refers to the communication link from the UEs to the base stations.

The base station may transmit control information and data to the UE. The control information may carry various parameters for data transmission. The UE may receive the control information and process the data transmission based on the control information to recover the data sent by the base station. It is desirable for the UE to interpret the control information from the base station appropriately.

Disclosure of Invention

Techniques for handling inconsistent control information in a wireless communication system are described. In an aspect, inconsistent control information may be handled differently for the downlink and uplink. In one design, a UE may receive a first grant with first control information for a first data transmission and may then receive a second grant with second control information for a second data transmission. The UE may determine that the second control information is inconsistent with the first control information. In one design, the first control information may carry a first transport block size and the second control information may carry a second transport block size. The UE may assume that the second control information is inconsistent with the first control information because the second transport block size is different from the first transport block size. The UE may determine whether to retain or discard the second grant based on whether the first grant and the second grant are for data transmission on the downlink or uplink.

In one design, the UE may retain the second grant if the first grant and the second grant are for data transmission on the downlink. The first grant and the second grant may be the two most recent grants for the transport block. Different data transmissions for the transport blocks may allow for different transport block sizes. The UE may compare the subsequent grant of the transport block with the second/most recent grant to detect for inconsistent control information.

In one design, the UE may discard the second grant if the first grant and the second grant are for data transmission on the uplink. The first grant may be an initial grant for a transport block and the second grant may be a most recent grant for the transport block. Different data transfers for the transport blocks may allow a single transport block size. The UE may compare the subsequent grant of the transport block with the first/initial grant to detect for inconsistent control information.

The inconsistent control information may also be detected and processed in other ways, as described below. Also as described below, the base station may process in a manner that allows for the UE to process inconsistent control information. Various aspects and features of the disclosure are described in further detail below.

Drawings

Fig. 1 shows a wireless communication system.

Fig. 2 shows data transmission with hybrid automatic repeat request (HARQ).

Fig. 3 shows an example of a UE receiving inconsistent control information.

Fig. 4 shows a process of receiving control information.

Fig. 5 shows a process of transmitting control information.

Fig. 6 shows a block diagram of a base station and a UE.

Detailed Description

The techniques described herein may be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA and other systems. The terms "system" and "network" are often used in a manner that enables interchange. A CDMA system may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), CDMA2000, and so on. UTRA includes wideband CDMA (wcdma), time division synchronous CDMA (TD-SCDMA), and other variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. TDMA systems may implement radio technologies such as global system for mobile communications (GSM). OFDMA systems may implement radio technologies such as evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11(Wi-Fi), IEEE 802.16(WiMAX), IEEE 802.20, Flash-OFDM, and so forth. UTRA and E-UTRA are part of the Universal Mobile Telecommunications System (UMTS). The 3GPP Long Term Evolution (LTE) and LTE-advanced (LTE-a) in Frequency Division Duplex (FDD) and Time Division Duplex (TDD) are newly released UMTS that utilize E-UTRA using OFDMA on the downlink and SC-FDMA on the uplink. UTRA, E-UTRA, UMTS, LTE-A and GSM are described in documents of the organization entitled "third Generation partnership project" (3 GPP). cdma2000 and UMB are described in documents of the organization entitled "third generation partnership project 2" (3GPP 2). The techniques described herein may be used for the aforementioned systems and radio technologies as well as for other systems and radio technologies. For clarity, some aspects of the techniques of this application are described below for LTE, and LTE terminology is used in much of the description below.

Fig. 1 illustrates a wireless communication system 100, which may be an LTE system or some other system. System 100 may include several evolved node bs (enbs) 110 and other network entities. An eNB may be an entity in communication with a UE and may also be referred to as a node B, a base station, an access point, and so on. Each eNB 110 may provide communication coverage for a particular geographic area and support communication for UEs located within this coverage area.

UEs 120 may be distributed throughout the system, and each UE may be stationary or mobile. A UE may also be called a mobile station, terminal, access terminal, subscriber unit, station, etc. A UE may be a cellular telephone, a Personal Digital Assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless telephone, a Wireless Local Loop (WLL) station, a smart phone, a netbook, a smartbook, and so forth.

The system may support HARQ to improve reliability of data transmission and to support rate matching for varying channel conditions. For HARQ, the transmitter may send a transmission of a transport block and, if necessary, one or more additional transmissions until the transport block is decoded correctly by the receiver, or a maximum number of transmissions is sent, or some other termination condition is encountered. The transport blocks may also be referred to as packets, codewords, and so on. The transmission of transport blocks may also be referred to as HARQ transmission, data transmission, and so on.

Fig. 2 shows an example of transmitting a data transmission on the downlink using HARQ. The transmission timeline may be divided into subframe units. Each subframe may cover a predetermined duration, e.g., 1 millisecond (ms) in LTE.

In the example shown in fig. 2, the eNB may have data to send to the UE and may process transport block a based on the transport format to obtain data symbols. The transport format may be associated with a Modulation and Coding Scheme (MCS), a Transport Block (TB) size, and/or other parameters of the transport block. The MCS may be associated with a modulation scheme/order (order), a code rate, and so on. The eNB may send Downlink Control Information (DCI) on a Physical Downlink Control Channel (PDCCH) and a first transmission of transport block a on a Physical Downlink Shared Channel (PDSCH) to the UE in subframe i. As described below, the DCI may carry various parameters for the first transmission.

The UE may receive DCI and a first transmission of transport block a from the eNB and may process the first transmission based on the DCI. The UE's decoding of transport block a may be erroneous and may send a Negative Acknowledgement (NACK) in subframe i + L, where L is the HARQ feedback delay, which may be equal to 2, 3, 4, etc. The eNB may receive the NACK and may send a new DCI on the PDCCH and a second transmission of transport block a on the PDSCH in subframe i + M, where M may be equal to 4, 6, 8, and so on. The UE may receive the DCI and a second transmission of transport block a from the eNB and process the first and second transmissions based on this DCI. The UE may decode transport block a correctly and may send an Acknowledgement (ACK) in subframe i + M + L. The eNB may receive the ACK and may then process and send another transport block B in a similar manner.

The system may support multiple HARQ processes. Each HARQ process may be active or inactive at any given moment, and one or more transport blocks may be transmitted in each active HARQ process. Once one or more transport blocks sent on the HARQ process terminate, one or more new transport blocks may be sent on the HARQ process.

The system may support synchronous HARQ and/or asynchronous HARQ. For synchronous HARQ, the transmission of a transport block may be sent in a subframe known a priori by the transmitter and receiver. For asynchronous HARQ, transport block transmissions may be scheduled and sent in any subframe. The techniques described herein may be used for both synchronous HARQ and asynchronous HARQ.

As shown in fig. 2, the eNB may transmit DCI to the UE with each transmission of a transport block. For a given transmission of a transport block, the DCI may include a PDCCH grant for the UE. The terms "grant" and "allocation" are often used in a manner that can be interchanged with one another. The PDCCH grant may include a New Data Indicator (NDI), MCS index, resource allocation information, and the like. The NDI may be inverted (toggled) for a first transmission of the transport block and may be maintained at the same value for each subsequent transmission of the transport block. (for semi-persistent scheduling, NDI may be set to '0' for a new transport block, or to '1' for another transmission of the current transport block.) the resource allocation information may indicate the number of resource blocks allocated to the UE for the transmission of the transport block. For LTE, the MCS index may be a 5-bit value ranging from 0 to 31. Each MCS index value ranging from 0 to 28 may be associated with a particular modulation order and a particular TBS index value. The TB size of the transport block may be determined based on the TBs index value and the number of allocated resource blocks. Each MCS index value within the range 29-31 may be associated with a particular modulation order for the downlink or with a particular redundancy version for the uplink but not with a TBS index value. The TB size of MCS indices ranging from 29 to 31 can be equal to the TB size of the latest PDCCH grant or the initial PDCCH grant of the same transport block, which should include MCS indices ranging from 0 to 28. (the difference between the latest and initial PDCCH grants is described below.) then, the TB size can be (i) carried explicitly by MCS indices ranging from 0 to 28, or (ii) carried implicitly by MCS indices ranging from 29 to 31. The DCI may also include other parameters for transport block transmission. For example, the DCI may include a HARQ process ID for data transmission on the downlink, an aperiodic Channel Quality Indicator (CQI) request on the uplink, and the like.

The UE may receive and process a transmission of a transport block based on DCI sent with the transmission. The UE may determine whether the transmission is of a new transport block or a current transport block based on whether the NDI is reversed. The UE may maintain a buffer to store log-likelihood ratios (LLRs) for soft symbols or transport blocks and may decode the transport blocks based on the soft symbols. (i) The UE may clear the buffer for the new transport block if the NDI is inverted, and (ii) may leave the buffer unchanged and use the soft symbols in the buffer to decode the current transport block if the NDI is not inverted. The UE may determine the TB size of the transport block based on the MCS index and the resource allocation for transmission. The UE may also obtain other parameters from the DCI and may process the transmission based on the DCI.

The UE may receive inconsistent control information, which may be defined in various ways. In one design, control information may be considered inconsistent if multiple PDCCH grants for the same transport block indicate different TB sizes. In another design, for a given parameter, the control information may be considered inconsistent if multiple PDCCH grants indicate different values. In yet another design, the control information may be deemed inconsistent if the parameter value is not among the set of allowed values for the parameter. For example, the number of allocated resource blocks may be limited to an integer multiple of 2, 3, or 5. In this case, a PDCCH grant with 7 allocated resource blocks would be considered to include inconsistent control information. The inconsistent control information may also be defined in other ways.

Fig. 3 illustrates an example of a UE receiving inconsistent control information. In the example shown in fig. 3, the UE receives a first PDCCH grant for a given HARQ process in subframe t, with the NDI reversed and the first TB size being TBs 1. The UE receives a second PDCCH grant for the same HARQ process in subframe t + M, where NDI is not reversed and the second TB size is TBs 2. The second TB size is different from the first TB size. The UE receives a third PDCCH grant for the same HARQ process in subframe t +2M, where NDI is not reversed and the second TB size is TBs 2.

As shown in fig. 3, the UE receives 3 PDCCH grants of the same HARQ process. These PDCCH grants may be (i) downlink assignments for data transmissions on the downlink to the UE, or (ii) uplink assignments for data transmissions on the uplink for the UE. Since the NDI is inverted only for the first PDCCH grant in subframe t and not for subsequent PDCCH grants in subframes t + M and t +2M, the UE interprets the 3 PDCCH grants in subframes t, t + M and t +2M as 3 transmissions of the same transport block. In general, a PDCCH grant when NDI is reversed and all subsequent PDCCH grants where NDI is not reversed can be treated as PDCCH grants for the same transport block. However, the TB sizes of the 3 PDCCH grants in fig. 3 are not uniform. In particular, the first PDCCH grant indicates a TB size of TBs1, while the two subsequent PDCCH grants indicate a TB size of TBs2, which is not equal to TBs 1.

Generally, the UE may receive inconsistent control information for data transmission on the downlink and/or inconsistent control information for data transmission on the uplink. The inconsistent control information for data transmission for each link may be defined by multiple PDCCH grants indicating the same transport block of different TB sizes. Inconsistent control information may be handled in various ways.

In a first scheme of handling inconsistent control information, different interpretations may be employed for inconsistent control information for the downlink and uplink. In one design, the downlink inconsistent control information may be retained and the uplink inconsistent control information may be discarded. For the downlink, retaining the inconsistent control information may result in (enterai) retaining the PDCCH grant with the inconsistent control information and possibly clearing the buffer at the UE so that the soft symbols of the new transport block may replace the soft symbols of the old transport block. This behavior is needed for the downlink, since the eNB may have traffic information, quality of service (QoS) information, and queue information for data to send to the UE. Therefore, the UE preferably follows the latest PDCCH grant from the eNB. For the uplink, dropping inconsistent control information may result in dropping the PDCCH grant with inconsistent control information and returning to a valid PDCCH grant. This behavior may be needed for the uplink, since the eNB does not have enough information about the data to be transmitted by the UE. Further, the inconsistent control information may be due to decoding errors at the UE.

For the first scheme, a transport block transmitted on the downlink may have one or more TB sizes. For the example shown in fig. 3, the second and third PDCCH grants will be treated as valid allocations. For corresponding second and third transmissions of the transport block in subframes t + M and t +2M, the second TB size TBs2 will replace the first TB size TBs 1. As described above, for a given PDCCH grant, if the MCS index is in the range of 0 ~ 28, the TB size of a transport block can be determined based on the MCS index and the number of allocated resource blocks. The TB size can be determined based on the latest PDCCH grant of the same transport block if the MCS index is in the range of 29-31, wherein the MCS index is in the range of 0-28.

For the first scheme, a transport block transmitted on the uplink may have only one TB size. For the example shown in fig. 3, both the second and third PDCCH grants will be discarded. In one design, a first PDCCH grant and a first TB size TBs1 may be used for second and third transmissions of a transport block sent in subframes t + M and t +2M, respectively. The TB size of each transmission of a transport block may be determined based on the TB size in the first/initial PDCCH grant of the transport block, since any inconsistent TB sizes of the transport block will be discarded. As described above, for a given PDCCH grant, if the MCS index is in the range of 0 ~ 28, the TB size of a transport block can be determined based on the MCS index and the number of allocated resource blocks. The TB size can be determined based on an initial PDCCH grant of the same transport block if the MCS index is in the range of 29-31, wherein the MCS index is in the range of 0-28. In another design, transmission on the uplink may be skipped for each PDCCH grant with inconsistent control information.

The behavior of the UE to retain the inconsistent control information for the downlink and to discard the inconsistent control information for the uplink is described in more detail below.

In a second scheme, inconsistent control information for both the downlink and uplink may be discarded. The inconsistent control information may result from different TB sizes of multiple PDCCH grants for the same transport block. Discarding inconsistent control information may cause the PDCCH grant with inconsistent control information to be discarded and returned to a valid PDCCH grant. For the example shown in fig. 3, the second PDCCH grant in subframe t + M may be discarded by the UE because the second TB size is not equal to the first TB size. For the downlink, the UE may reserve a buffer of soft symbols obtained from previous transmissions of the transport block. For the uplink, the UE may skip transmitting the transport block in subframe t + M. This behavior of the uplink may also be applied to the first scheme.

For the second scheme, a PDCCH grant may be discarded if it includes control information that is deemed inconsistent. The dropped PDCCH grant is no longer used for future reference. Instead, the initial PDCCH grant may be used as a reference for comparison with subsequent PDCCH grants of the same transport block. For the example shown in fig. 3, the UE may compare the third PDCCH grant received in subframe t +2M with the first PDCCH grant received in subframe t, since the second PDCCH grant has been discarded. In this example, the UE will also drop the third PDCCH grant because it includes control information that is inconsistent with the first PDCCH grant in subframe t (since the TB size of the third PDCCH grant is not the same as the TB size of the first PDCCH grant).

For the uplink, the UE may correctly receive the first PDCCH grant and may acquire the TB size TBs 1. The UE may then grant transmission of a transport block of size TBS1 for the first PDCCH. Alternatively, the UE may miss the first PDCCH grant but correctly receive the second PDCCH grant and obtain the TB size TBs 2. In this case, the UE may not send the transmission of the first PDCCH grant, but may send the transmission of a transport block of size TBS2 for the second PDCCH grant. The eNB may perform blind decoding/detection and may attempt to decode transmissions from the UE based on different TB sizes TBs1 and TBs 2. This behavior of the uplink may also be applied to the first scheme.

In a third aspect, inconsistent control information for both the downlink and uplink may be retained. Reserving the inconsistent control information may cause a PDCCH grant with the inconsistent control information to be reserved and used. For the third scheme, the transport blocks may have different TB sizes. For the example shown in fig. 3, the UE may retain the second PDCCH grant received in subframe t + M even though the second TB size is not equal to the first TB size. For the downlink, the UE may process a second transmission of the transport block based on a second PDCCH grant. For the uplink, the UE may replace the current PDU constructed based on the first TB size TBs1 with a new Protocol Data Unit (PDU) constructed based on the second TB size TBs 2. The UE may continue to update or retain other HARQ parameters, which should not be affected by the inconsistent control information. For example, the UE may continue to increment (rather than reset) the CURRENT TX NB parameter, which represents the number of transmissions sent for a transport block. Similarly, the UE may retain the third PDCCH grant received in subframe t + 2M.

For the downlink and uplink, the UE may receive a PDCCH grant with an MCS index in the range of 0-28, and may determine the TB size based on the MCS index and the number of allocated resource blocks. The UE may also receive a PDCCH grant with an MCS index in the range of 29-31 and may determine the TB size based on the latest PDCCH grant of the same transport block with the MCS index in the range of 0-28. For the example shown in fig. 3, the second PDCCH grant in subframe t + M may include an MCS index in the range of 0-28 to carry the second TB size TBs 2. If the third PDCCH grant in subframe t +2M includes MCS indices in the range of 29-31, the second TB size TBs2 from the second PDCCH grant may be used for the third transmission of the transport block in subframe t + 2M. This behavior may be applied to the first scenario.

The UE may correctly receive the second PDCCH grant and may acquire the second TB size indicated by the MCS index ranging from 0 to 28. The third PDCCH grant may include an MCS index ranging from 29 to 31, and the UE may then use the second TB size of the second PDCCH grant from the same transport block. However, if the UE misses the second PDCCH grant but correctly receives a third PDCCH grant with an MCS index in the range of 29-31, the UE can use the first TB size from the first PDCCH grant. The UE may thus use a different TB size for the third transmission depending on whether the second PDCCH grant was received correctly or in error. The eNB may blindly decode transmissions from the UE for different TB sizes to account for PDCCH grants missed by the UE.

In the fourth scheme, inconsistent control information for downlink and uplink may be avoided by no change in the parameter of interest of a PDCCH grant specifying the same transport block. For example, for the same NDI in the same HARQ process, the TB size may be specified to be the same for all PDCCH grants. This may avoid different TB sizes due to eNB scheduling. The eNB may send PDCCH grants with the same TB size, but the UE may receive different TB sizes due to decoding errors. Thus, the first, second or third scheme described above may be used to handle different TB sizes received by the UE.

Table 1 summarizes the 4 schemes described previously for handling inconsistent control information.

TABLE 1-schemes for handling inconsistent control information

The UE may receive a PDCCH grant with an MCS index in the range of 29-31. If inconsistent control information is retained, the UE may determine the TB size of the current PDCCH grant based on the latest PDCCH grant of the same transport block with MCS index in the range of 0-28. If inconsistent control information is discarded, the UE may determine the TB size of the current PDCCH grant whose MCS index should be in the range of 0-28 based on the initial PDCCH grant of the same transport block. The foregoing behavior is applicable to both the downlink and uplink.

Fig. 4 shows a design of a process 400 for receiving control information in a wireless communication system. Process 400 may be performed by a UE (as described below) or some other entity. The UE may receive a first grant with first control information for a first data transmission (block 412). The UE may then receive a second grant with second control information for a second data transmission (block 414). The UE may receive the first grant and the second grant in different time intervals (e.g., in different subframes). The UE may determine that the second control information is inconsistent with the first control information (block 416). The UE may determine whether to retain or discard the second grant based on whether the first grant and the second grant are for data transmission on the downlink or uplink (block 418). The UE may also determine whether to retain or discard the second grant based further on whether the first grant and the second grant are for the same transport block, which may be determined based on the NDI and HARQ process ID sent in each grant. The HARQ process ID may be indicated explicitly (e.g., for downlink grants) or implicitly (e.g., for uplink grants).

In one design of block 416, the first control information may include a first value of a parameter and the second control information may include a second value of the parameter. The second control information may be deemed inconsistent with the first control information due to the second value being different from the first value. In another design, the first control information may include a first transport block size and the second control information may include a second transport block size. The second control information may be deemed inconsistent with the first control information due to the second transport block size being different from the first transport block size. Inconsistent control information may also be determined in other ways.

In block 418, for the first scheme described previously, the UE may retain the second grant if the first and second grants are for data transmission on the downlink. The first grant and the second grant may be the two most recent grants of the transport block. Different transport block sizes may be allowed for different data transmissions of the transport block. The UE may compare the subsequent grant of the transport block to the second/most recent grant to detect for inconsistent control information. The second grant may not carry an explicit transport block size for the transport block. For example, the second grant may include an MCS index in the range of 29-31. The UE may determine the transport block size for the second data transmission based on the most recent grant of a transport block with an explicit transport block size, e.g., with an MCS index in the range of 0-28.

In block 418, for the first scheme described previously, the UE may discard the second grant if the first and second grants are for data transmission on the uplink. The first grant may be an initial grant for a transport block and the second grant may be a most recent grant for the transport block. A single transport block size may be allowed for different data transfers of the transport block. The UE may compare the subsequent grant of the transport block with the first/initial grant to detect for inconsistent control information. The initial grant may carry an explicit transport block size, e.g., may have an MCS index in the range of 0-28. The second grant may not carry an explicit transport block size, e.g., may have an MCS index in the range of 29-31. The UE may determine the transport block size for the second data transmission based on the transport block size that is explicit in the initial grant.

The UE may also retain or discard the second grant in other manners. For example, the UE may retain or discard the second grant based on the second, third, or fourth scheme described above.

In one design, the first grant and the second grant may be for data transmission on a downlink. The UE may receive and process the first data transmission based on the first control information. The UE may also receive and process a second data transmission based on the second control information. In another design, the first grant and the second grant may be for data transmission on the uplink. The UE may send a first data transmission based on the first control information. The UE may skip sending the second data transmission because the second control information is inconsistent with the first control information. Alternatively, the UE may send the second data transmission based on the first control information.

Fig. 5 shows a design of a process 500 for transmitting control information in a wireless communication system. Process 500 may be performed by a base station/eNB (as described below) or some other entity. The base station may send a first grant with first control information for a first data transmission to the UE (block 512). The base station may also send a second grant with second control information for a second data transmission to the UE (block 514). The UE may assume that the second control information is inconsistent with the first control information. For example, the first control information may include a first transport block size, and the second control information may include a second transport block size. The UE may assume that the second control information is inconsistent with the first control information because the second transport block size is different from the first transport block size.

The base station may process the first data transmission and the second data transmission based on whether the first grant and the second grant are for data transmission on the downlink or the uplink (block 516). In one design, the first grant and the second grant may be for data transmission on a downlink. The base station may send a first data transmission based on the first control information and may send a second data transmission based on the second control information. In another design, the first grant and the second grant may be for data transmission on the uplink. The base station may receive and process the first data transmission based on the first control information and may also receive and process the second data transmission based on the second control information. The base station may perform blind decoding for the second data transmission if a decoding error is obtained for the second data transmission when processing the second data transmission based on the second control information.

Fig. 6 shows a block diagram of a design of base station/eNB 110 and UE 120, which may be one of the base stations/enbs and one of the UEs in fig. 1. The base station 110 may have T antennas 634a 634T and the UE 120 may have R antennas 652a 652R, where generally T ≧ 1 and R ≧ 1.

At base station 110, a transmit processor 620 may receive data for one or more UEs from a data source 612 and control information (e.g., PDCCH grants) from a controller/processor 640. Processor 620 may process (e.g., encode, interleave, and modulate) the data and control information to obtain data symbols and control symbols, respectively. A Transmit (TX) multiple-input multiple-output (MIMO) processor 630 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide T output symbol streams to T Modulators (MODs) 632 a-632T. Each modulator 632 may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 632 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 632 a-632T may be transmitted through T antennas 634 a-634T, respectively.

At the UE 120, the antennas 652a through 652r may receive downlink signals from the base station 110 and provide received signals to demodulators (DEMODs) 654a through 654r, respectively. Each demodulator 654 may condition (e.g., filter, amplify, downconvert, and digitize) its received signal to obtain input samples. Each demodulator 654 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 656 may acquire received symbols from all R demodulators 654 a-654R, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. A receive processor 658 may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for UE 120 to a data sink 660, and provide decoded control information to a controller/processor 680.

On the uplink, at UE 120, a transmit processor 664 may receive and process data from a data source 662, and control information from a controller/processor 680. The symbols from transmit processor 664 may be precoded by a TX MIMO processor 666 (if applicable), further processed by modulators 654a through 654r (e.g., SC-FDM, etc.), and transmitted to base station 110. At base station 110, the uplink signals from UE 120 may be received by antennas 634, processed by demodulators 632, detected by a MIMO detector 636 if applicable, and further processed by a receive processor 638 to obtain the decoded data and control information sent by UE 120. The processor 638 may provide the decoded data to a data sink 639 and the decoded control information to the controller/processor 640.

Controllers/processors 640 and 680 may direct operation at base station 110 and UE 120, respectively. Processor 640 and/or other processors and modules at base station 110 may perform or direct process 500 in fig. 5 and/or other processes for the techniques described herein. Processor 680 and/or other processors and modules at UE 120 may perform or direct process 400 in fig. 4 and/or other processes for the techniques described herein. Memories 642 and 682 may store data and program codes for base station 110 and UE 120, respectively. A scheduler 644 may schedule UEs for data transmission on the downlink and/or uplink.

In one configuration, wireless communications apparatus 110 can include means for sending a first grant with first control information for a first data transmission to a UE, means for sending a second grant with second control information for a second data transmission to the UE, and means for processing the first data transmission and the second data transmission based on whether the first grant and the second grant are for data transmission on a downlink or an uplink. The modules may be processors 620, 638, and/or 640 to perform the functions of the modules. The above modules may also be modules or any means for performing the functions of the above modules.

In another configuration, the wireless communication apparatus 120 can include means for receiving a first grant with first control information for a first data transmission, means for receiving a second grant with second control information for a second data transmission, means for determining that the second control information is inconsistent with the first control information, and means for determining whether to retain or discard the second grant based on whether the first grant and the second grant are for data transmission on a downlink or uplink. The aforementioned means may be processor 658 and/or 680 for performing the functions of the aforementioned means. The above modules may also be modules or any means for performing the functions of the above modules.

Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The various illustrative logical blocks, modules, and circuits described in connection with the application may be implemented or performed with a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The steps of a method or algorithm described in connection with the present application may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.

In one or more exemplary designs, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media may be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any suitable connection is termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes Compact Disc (CD), laser disc, optical disc, Digital Versatile Disc (DVD), floppy disk and blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above should also be included within the scope of computer-readable media.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the present application is not intended to be limited to the examples and designs presented herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (30)

1. A method of wireless communication performed by a user equipment, comprising:

receiving a first grant with first control information for a first data transmission of a transport block;

receiving a second grant with second control information for a second data transmission of the transport block;

determining that the second control information is inconsistent with the first control information, wherein the first control information includes a first value of a parameter and the second control information includes a second value of the parameter, and wherein the second control information is deemed inconsistent with the first control information due to the second value being different from the first value;

discarding the second grant if the first grant and the second grant are for data transmission of the transport block on an uplink; and

reserving the second grant if the first grant and the second grant are for data transmission of the transport block on a downlink.

2. The method of claim 1, wherein the first control information comprises a first transport block size and the second control information comprises a second transport block size, and wherein the second control information is deemed to be inconsistent with the first control information due to the second transport block size being different from the first transport block size.

3. The method of claim 1, wherein the first grant and the second grant are the last two grants for the transport block, and wherein a subsequent grant for the transport block is compared to the second grant to detect inconsistent control information.

4. The method of claim 1, wherein different transport block sizes are allowed for different data transmissions of a transport block.

5. The method of claim 1, wherein the second grant does not carry an explicit transport block size for the transport block, the method further comprising:

determining a transport block size for the second data transmission based on a most recent grant for the transport block having an explicit transport block size.

6. The method of claim 1, wherein the first grant is an initial grant for the transport block, wherein the second grant is a most recent grant for the transport block, and wherein a subsequent grant for the transport block is compared to the first grant to detect inconsistent control information.

7. The method of claim 1, wherein a single transport block size is allowed for different data transmissions of a transport block.

8. The method of claim 6, wherein the initial grant carries an explicit transport block size and the second grant does not carry an explicit transport block size, the method further comprising:

determining a transport block size for the second data transmission based on the transport block size that is explicit in the initial grant.

9. The method of claim 1, further comprising:

receiving and processing the first data transmission based on the first control information; and

receiving and processing the second data transmission based on the second control information.

10. The method of claim 1, further comprising:

sending the first data transmission based on the first control information; and

not sending the second data transmission because the second control information is inconsistent with the first control information.

11. A wireless communications apparatus, comprising:

means for receiving a first grant having first control information for a first data transmission of a transport block;

means for receiving a second grant with second control information for a second data transmission of the transport block;

means for determining that the second control information is inconsistent with the first control information, wherein the first control information comprises a first value of a parameter and the second control information comprises a second value of the parameter, and wherein the second control information is deemed inconsistent with the first control information because the second value is different from the first value;

means for discarding the second grant if the first grant and the second grant are for data transmission of the transport block on an uplink; and

means for reserving the second grant if the first grant and the second grant are for data transmission of the transport block on a downlink.

12. The apparatus of claim 11, wherein the first control information comprises a first transport block size and the second control information comprises a second transport block size, and wherein the second control information is deemed to be inconsistent with the first control information due to the second transport block size being different from the first transport block size.

13. The apparatus of claim 11, wherein the first grant and the second grant are the last two grants for the transport block, and wherein a subsequent grant for the transport block is compared to the second grant to detect inconsistent control information.

14. The apparatus of claim 11, wherein the first grant is an initial grant for the transport block, wherein the second grant is a most recent grant for the transport block, and wherein a subsequent grant for the transport block is compared to the first grant to detect for inconsistent control information.

15. A wireless communications apparatus, comprising:

at least one processor configured to:

receiving a first grant with first control information for a first data transmission of a transport block,

receiving a second grant with second control information for a second data transmission of the transport block,

determining that the second control information is inconsistent with the first control information, wherein the first control information includes a first value of a parameter and the second control information includes a second value of the parameter, and wherein the second control information is deemed inconsistent with the first control information due to the second value being different from the first value,

discarding the second grant if the first grant and the second grant are for data transmission of the transport block on an uplink; and

reserving the second grant if the first grant and the second grant are for data transmission of the transport block on a downlink.

16. The apparatus of claim 15, wherein the first control information comprises a first transport block size and the second control information comprises a second transport block size, and wherein the second control information is deemed to be inconsistent with the first control information due to the second transport block size being different from the first transport block size.

17. The apparatus of claim 15, wherein the first grant and the second grant are the last two grants for the transport block, and wherein a subsequent grant for the transport block is compared to the second grant to detect inconsistent control information.

18. The apparatus of claim 15, wherein the first grant is an initial grant for the transport block, wherein the second grant is a most recent grant for the transport block, and wherein a subsequent grant for the transport block is compared to the first grant to detect for inconsistent control information.

19. A method of wireless communication performed by a base station, comprising:

transmitting a first grant with first control information for a first data transmission of a transport block to a User Equipment (UE);

transmitting a second grant to the UE with second control information for a second data transmission of the transport block, wherein the second control information is deemed by the UE to be inconsistent with the first control information, wherein the first control information includes a first value of a parameter, the second control information includes a second value of the parameter, and wherein the second control information is deemed to be inconsistent with the first control information due to the second value being different from the first value; and

processing the first and second data transmissions based on whether the first and second grants are for data transmissions on the downlink or uplink, wherein the second grant is discarded if the first and second grants are for data transmissions of the transport block on the uplink and retained if the first and second grants are for data transmissions of the transport block on the downlink.

20. The method of claim 19, wherein the first control information comprises a first transport block size and the second control information comprises a second transport block size, and wherein the second control information is deemed inconsistent with the first control information by the UE due to the second transport block size being different from the first transport block size.

21. The method of claim 19, wherein processing the first data transmission and the second data transmission comprises:

sending the first data transmission based on the first control information; and

sending the second data transmission based on the second control information.

22. The method of claim 19, wherein processing the first data transmission and the second data transmission comprises:

receiving and processing the first data transmission based on the first control information;

receiving and processing the second data transmission based on the second control information; and

blindly decoding the second data transmission if a decoding error occurs for the second data transmission.

23. A wireless communications apparatus, comprising:

means for sending a first grant with first control information for a first data transmission of a transport block to a User Equipment (UE);

means for transmitting a second grant to the UE with second control information for a second data transmission of the transport block, wherein the second control information is deemed by the UE to be inconsistent with the first control information, wherein the first control information includes a first value of a parameter and the second control information includes a second value of the parameter, and wherein the second control information is deemed to be inconsistent with the first control information due to the second value being different from the first value; and

means for processing the first data transmission and the second data transmission based on whether the first grant and the second grant are for data transmission on a downlink or an uplink, wherein the second grant is discarded if the first grant and the second grant are for data transmission of the transport block on an uplink and retained if the first grant and the second grant are for data transmission of the transport block on a downlink.

24. The apparatus of claim 23, wherein the first control information comprises a first transport block size and the second control information comprises a second transport block size, and wherein the second control information is deemed inconsistent with the first control information by the UE due to the second transport block size being different from the first transport block size.

25. The apparatus of claim 23, wherein means for processing the first data transmission and the second data transmission comprises:

means for sending the first data transmission based on the first control information; and

means for transmitting the second data transmission based on the second control information.

26. The apparatus of claim 23, wherein means for processing the first data transmission and the second data transmission comprises:

means for receiving and processing the first data transmission based on the first control information;

means for receiving and processing the second data transmission based on the second control information; and

means for blindly decoding the second data transmission if a decoding error occurs for the second data transmission.

27. A wireless communications apparatus, comprising:

at least one processor configured to:

transmitting a first grant with first control information for a first data transmission of a transport block to a User Equipment (UE),

sending a second grant to the UE with second control information for a second data transmission of the transport block, wherein the second control information is deemed by the UE to be inconsistent with the first control information, wherein the first control information includes a first value of a parameter and the second control information includes a second value of the parameter, and wherein the second control information is deemed to be inconsistent with the first control information due to the second value being different from the first value, and

processing the first and second data transmissions based on whether the first and second grants are for data transmissions on the downlink or uplink, wherein the second grant is discarded if the first and second grants are for data transmissions of the transport block on the uplink and retained if the first and second grants are for data transmissions of the transport block on the downlink.

28. The apparatus of claim 27, wherein the first control information comprises a first transport block size and the second control information comprises a second transport block size, and wherein the second control information is deemed inconsistent with the first control information by the UE due to the second transport block size being different from the first transport block size.

29. The apparatus of claim 27, wherein the at least one processor is configured to:

sending the first data transmission based on the first control information, an

Sending the second data transmission based on the second control information.

30. The apparatus of claim 27, wherein the at least one processor is configured to:

receiving and processing the first data transmission based on the first control information,

receiving and processing the second data transmission based on the second control information, an

Blindly decoding the second data transmission if a decoding error occurs for the second data transmission.