KR20120122903A - Method of handling soft buffer for carrier aggregation and related communication device - Google Patents

Abstract

PURPOSE: A method for processing a soft buffer for carrier aggregation and a related communication device are provided to reduce each partition size of the soft buffer by dividing the soft buffer into partitions which store an HARQ(hybrid automatic request) process. CONSTITUTION: A process starts(700). A plurality of weighted values corresponding to a plurality of CC(Component Carrier)s is determined for the soft buffer according to instructions(702). A plurality of sizes of a plurality of sub blocks is determined according to the plurality of weighted values(704). The soft buffer is divided into the plurality of sub blocks according to the plurality of sizes of the plurality of sub blocks. A plurality of HARQ processes with respect to the plurality of CCs is prepared in the plurality of sub blocks(706). The process is completed(708). [Reference numerals] (700) Start; (702) Determination of a plurality of weighted values corresponding to a plurality of CCs for a soft buffer according to instructions; (704) Determination of a plurality of sizes of a plurality of sub blocks according to the plurality of weighted values; (706) Preparation of a plurality of HARQ processes for the plurality of CCs in the plurality of sub blocks by dividing the soft buffer into the plurality of sub blocks according to the plurality of sizes of the plurality of sub blocks; (708) End

Description

METHOD OF HANDLING SOFT BUFFER FOR CARRIER AGGREGATION AND RELATED COMMUNICATION DEVICE}

TECHNICAL FIELD The present invention relates to a method of processing soft buffers for carrier integration and related communication devices in a wireless communication system.

Long-term evolution to support 3GPP Rel-8 and / or 3GPP Rel-9 standards, the successor to UMTS, to further enhance the performance of universal mobile telecommunications systems (UMTS) to meet the increasing needs of users. A long-term evolution (LTE) system was developed by the 3rd Generation Partnership Project (3GPP). LTE systems include new air interfaces and new wireless network architectures that provide high data rates, low latency, packet optimization, and improved system capabilities and coverage. In an LTE system, a radio access network, known as an evolved UTRAN (E-UTRAN), communicates with a number of user equipments (UEs) and is mobile for non access stratum (NAS) control. And a plurality of evolved Node-Bs (eNBs) in communication with a core network including a mobility management entity (MME), a serving gateway, and the like.

The LTE-advanced (LTE-advanced, LTE-A) system, as its name suggests, is an evolution of the LTE system. The LTE-A system aims for faster switching between power states and improves performance at the coverage edge of the eNB. The LTE-A system also includes carrier aggregation (CA), coordinated multipoint transmission / reception (CoMP), uplink (UL), and multiple-input multiple-output. , MIMO), and the like. In order for a UE and an eNB to communicate with each other in an LTE-A system, the UE and the eNB must support a standard developed for an LTE-A system such as a 3GPP Rel-10 standard or a later version.

LTE-A systems introduce CAs in which one or more component carriers (CCs) are integrated to achieve wider band transmission. Therefore, LTE-A system can support a wider bandwidth up to 100MHz by integrating up to 5 CC, each CC has a maximum bandwidth of 20MHz and is backward compatible with the 3GPP Rel-8 standard. The LTE-A system supports CAs for both adjacent and non-neighbor CCs, and each CC is limited to a maximum of 110 resource blocks. CA increases bandwidth flexibility by integrating CC.

If the UE is configured as a CA, the UE has the ability to transmit and / or receive packets with one or multiple CCs to increase throughput. In an LTE-A system, an eNB may configure a UE having a different number of UL and downlink (DL) CCs. In addition, the CC configured in the UE necessarily consists of one DL primary CC (PCC) and one UL PCC. The most important characteristic of DL PCC and UL PCC is the exchange of control information between UE and eNB. CCs other than PCC are named UL or DL secondary CCs (SCCs). The number of UL and DL SCCs is arbitrary and relates to the UL and DL aggregation capabilities of the UE and the available radio resources.

In an LTE system, a hybrid automatic repeat request (HARQ) process is used to provide efficient and reliable communication. Unlike the automatic retransmission request (ARQ) process, a forward error correcting code (FEC) is used in the HARQ process. For example, if the receiver decodes the packet correctly, the receiver feeds back an acknowledgment (ACK) to inform the transmitter that the packet was received correctly. Conversely, if the receiver does not decode the packet correctly, the receiver feeds back a negative acknowledgment (NACK) to the transmitter. In this situation, the UE stores some or all of the packets in the soft buffer of the UE. After receiving the retransmitted packet from the transmitter, the UE combines the soft value of the retransmitted packet and the stored packet. The receiver decodes the packet using the combined soft value. In addition, the combination of previously incorrectly received packet (s) and the currently received packet increases the probability of success in decoding. The UE continues the HARQ process until the packet is decoded correctly or until the maximum number of retransmissions are sent, where the HARQ process declares a failure and ARQ in radio link control (RLC) to retry. Leave the process up. In other words, the space of the soft buffer must be reserved for the HARQ process so that the UE can store the HARQ process that was not correctly decoded. Otherwise, if the soft buffer is fully used, the UE blocks the HARQ process. When a plurality of packets are sent to the UE, the UE may have to store the plurality of HARQ processes due to the decoding failure of the packet.

In detail, the UE may store up to eight HARQ processes in a soft buffer of an LTE system (ie, a single CC system). A transport block (TB) is a physical interface between an eNB and a UE and corresponds to data carried in an LTE radio subframe. In addition, each LTE radio subframe is 1 millisecond (ms), each LTE radio frame is 10 ms, and consists of 10 LTE radio subframes. Using MIMO (eg, spatial multiplexing), one or more transport blocks may be transmitted per transmission time interval (TTI) for the UE.

The soft buffer partition rule in an LTE system (ie, a single CC system) is introduced as follows. As shown in the table of FIG. 10, the total number of soft channel bits (N _soft ) depends on the UE category of the UE, and various N _soft values are listed according to the example of the prior art. N _soft can be divided into multiple partitions according to the following equation:

In the above equation, N _IR is the size of a partition used for storing a transport block. N _soft is the total number of soft channel bits of the UE. K _MIMO is the number of transport blocks that can be transmitted to the UE in TTI and is related to the MIMO used by the UE and the network. In general, when spatial multiplexing of n spatial streams is configured in the UE, K _MIMO is set to n. M _limit is a positive value equal to eight. M _{DL _ HARQ} is the maximum number of DL HARQ processes per serving cell and corresponds to the duplex mode and its configuration. For example, M _{_ DL HARQ} is set to 8 for a frequency division duplex (frequency-division duplexing, FDD) . The values 4, 7, 10, 9, 12, 15, and 6 are time-division duplexing (TDD) UL / DL configurations 0, 1, respectively, as shown in table 20 of FIG. 2, is used in the 3, 4, 5, and 6, are listed in accordance with an example of _{dL _} M different values of the _HARQ dl prior art. min (x, y) returns the smaller of x and y.

As shown in Equation 1, up to min (MD _{L _ HARQ} , M _limit ) HARQ processes can be stored in the soft buffer. If spatial multiplexing of K _MIMO dog spatial streams is configured in the UE, each HARQ process consists of K _MIMO dog transport blocks. Therefore, the entire soft buffer is divided into K _MIMO min (M _{DL _ HARQ} , M _limit ) partitions. Each partition consists of N _IR soft channel bits that can be used to store one transport block.

Referring to FIG. 3, FIG. 3 is a schematic diagram of a soft buffer SBp according to the prior art. In this example, spatial multiplexing is not configured in the UE (ie, K _MIMO = 1), and the soft buffer SB _P is divided into eight partitions (P301-P308) for storing eight HARQ processes. M _{DL _ HARQ} is 8 or more. N _soft is the size (eg, number of bits) of the soft buffer S _BP and depends on the UE category of the UE. N _IR is the number of bits in the partition of the soft buffer (S _BP ). Therefore, a transport block of maximum size N _IR may be stored in a corresponding partition, and at most eight HARQ processes may be stored in a soft buffer S _BP .

However, if multiple CCs are configured in the UE, the UE may have to store more than eight HARQ processes in the soft buffer of the LTE-A system. For example, if the UE is configured with 5 DL CCs and operated in FDD duplex mode, the UE needs to store up to 40 HARQ processes due to the decoding failure of the packet. In LTE-system with multiple CCs, there are two solutions. In the first solution, the soft buffer partition rule is the same as that of the LTE system (ie single CC system). In other words, up to eight HARQ processes can be stored in the soft buffer. All bad HARQ processes can share soft buffers statistically. Thus, the blocking probability of the HARQ process increases, and the system throughput decreases. In the second solution, the soft buffer can be divided into 40 partitions to simply store up to 40 HARQ processes, and the size of each partition of the soft buffer is reduced. In each case of a faulty HARQ process, the number of soft channel bits that the UE can store is reduced as the size of the corresponding partition decreases. As a result, coding performance is reduced, more retransmissions are required, and system throughput is reduced. Clearly, neither the first nor the second solution can achieve optimal system throughput. Thus, when a CA is configured in a UE, a method of processing the soft buffer of the UE for storing the HARQ process is a topic to be discussed and solved.

With this in mind, the present application aims to provide a method of processing a soft buffer for carrier integration and a communication device of a wireless communication system in order to solve the above problem.

This object is achieved by a soft buffer processing method and communication device for carrier integration according to claims 1, 2, 13 and 14 of the claims. Dependent claims relate to further developments and improvements.

As will be clearer from the detailed description below, a method of processing a soft buffer of a mobile device in a wireless communication system is disclosed. The mobile device is composed of a plurality of element carriers (hereinafter referred to as CCs) by a network of a wireless communication system. The plurality of CCs includes a primary CC (hereinafter referred to as PCC) and one or more secondary CCs (hereinafter referred to as SCC). The method described in the claims includes determining a plurality of weights corresponding to the plurality of CCs according to an indication; Determining a plurality of sizes of the plurality of subblocks according to the plurality of weights; And dividing the soft buffer into the plurality of subblocks according to the plurality of sizes of the plurality of subblocks, and requesting a plurality of hybrid automatic retransmission requests for the plurality of CCs to the plurality of subblocks (hereinafter, referred to as HARQ). Preparing the process.

1 is a table showing the number N _soft of soft channel bits according to an example of the prior art.
Figure 2 is a table showing the maximum number M of _{HARQ DL _} DL HARQ processes according to the example of the prior art.
3 is a schematic diagram of a soft buffer according to an example of the prior art.
4 is a schematic diagram of a wireless communication system according to an example of the present invention.
5 is a schematic diagram of a communication device according to an example of the present invention.
6 is a schematic diagram of a communication protocol layer of a wireless communication system.
7 is a flowchart of a process according to an example of the present invention.
8 is a schematic diagram of a soft buffer according to an example of the present invention.
9 is a table illustrating weights w _PCC according to an example of the present invention.
10 is a flowchart of a process according to an example of the present invention.
11 is a schematic diagram of a soft buffer according to an example of the present invention.
12 to 14 are tables illustrating weight M _overbooking according to an example of the present invention.
15 is a schematic diagram of a soft buffer according to an example of the present invention.
16 is a schematic diagram of a soft buffer according to an example of the present invention.

4, FIG. 4 is a schematic diagram of a wireless communication system 40 in accordance with an example of the present invention. Wireless, such as long term evolution-advanced (LTE-A) systems or other mobile communication systems that support carrier aggregation (CA) (e.g., multiple component carriers (CC)) The communication system 40, in brief, is composed of a network and a plurality of user equipments (UEs). In FIG. 4, the network and the UE are simply used to describe the structure of the wireless communication system 40. In practice, the network may be referred to as an E-UTRAN including a plurality of eNBs and repeaters in an LTE-A system. The UE may be a mobile device such as a mobile phone, a laptop, a tablet computer, an e-book, and a portable computer system. In addition, the network and the UE may be viewed as a transmitter or a receiver depending on the transmission direction. For example in the case of uplink (UL) the UE is the transmitter and the network is the receiver, in the case of the downlink (DL) the network is the transmitter and the UE is the receiver.

5, FIG. 5 is a schematic diagram of a communication device 50 according to an example of the present invention. The communication device 50 may be, but is not limited to, the UE or network shown in FIG. 4. The communication device 50 may include a processor 500, such as a microprocessor or ASIC, a storage unit 510, and a communication interfacing unit 520. The storage unit 510 can be any data storage device capable of storing program code 514 accessed by the processor 500. Examples of the storage unit 510 include subscriber identity module (SIM), read-only memory (ROM), flash memory, random access memory (RAM), CD-ROM / DVD-ROM, magnetic tape, hard disk and optical data storage device. Including but not limited to. The communication interfacing unit 520 is preferably a wireless transceiver and can exchange radio signals with the network depending on the processing result of the processor 500.

Referring to FIG. 6, FIG. 6 shows a schematic diagram of a communication protocol layer of a wireless communication system 40. The operations of some of the communication protocol layers may be defined in program code 514 and executed by processor 500. The communication protocol layer from the top down is the radio resource control (RRC) layer 600, the packet data convergence protocol (PDCP) layer 602, the radio link control (RLC) layer 604, the medium access control (MAC) layer ( 606 and physical (PHY) layer 608. The RRC layer 600 is used to perform broadcast, paging, RRC connection management, measurement reporting and control, radio bearer control generation and radio bearer release. PDCP layer 602 is used to protect and encrypt the integrity of the transmission, and to maintain a delivery order during handover. The RLC layer 604 is used to maintain segmentation / concatenation of packets and delivery sequences when packets are lost. The MAC layer 606 is responsible for maintaining the hybrid automatic retransmission request (HARQ) process, multiplexed logical channels, random access procedures, and UL timing alignment. In each HARQ process, an acknowledgment (ACK) is reported when the MAC data / control packet is received and successfully decoded. Otherwise, a negative acknowledgment (NACK) is reported. The PHY layer 608 is used to provide physical channels to UEs and networks (eg, eNBs and / or repeaters). 6 merely conceptually illustrates the operation of a communication protocol layer, the details of which may be different for LTE-systems and other communication systems.

Referring to FIG. 7, FIG. 7 is a flowchart of a process 70 in accordance with an example of the present invention. Process 70 is used to process the soft buffer of the UE, in the UE and network shown in FIG. The UE is composed of a plurality of CCs by a network, the plurality of CCs comprising a primary CC (PCC) and at least one secondary CC (SCC). Process 70 may be compiled into program code 514 and includes the following steps:

Step 700: Start process 70.

Step 702: Determine a plurality of weights corresponding to the plurality of CCs for the soft buffer according to the instruction.

Step 704: Determine a plurality of sizes of the plurality of subblocks according to the plurality of weights.

Step 706: The soft buffer is divided into a plurality of subblocks according to a plurality of sizes of the plurality of subblocks, thereby preparing a plurality of HARQ processes for the plurality of CCs in the plurality of subblocks.

708: The process 70 ends.

According to process 70, the UE determines a plurality of weights corresponding to the plurality of CCs for the soft buffer according to the indication. Thereafter, the UE determines a plurality of sizes for the plurality of subblocks according to the plurality of weights. Accordingly, the UE may divide the plurality of subblocks according to the plurality of sizes of the plurality of subblocks and prepare a plurality of HARQ processes for the plurality of CCs in the plurality of subblocks. In other words, the UE prepares (eg stores) a plurality of HARQ processes for the PCC and at least one SCC in subblocks of various sizes (and thus in partitions of various sizes). For example, since the packets sent to the PCC are more important (e.g., including control information) and the number of packets (i.e., traffic load) is high, the HARQ process of the PCC may be larger (e.g., using large weights). Can be prepared in subblocks of size. Since packets sent to the SCC are less important and the number of packets is small, the HARQ process for at least one SCC can be prepared in a smaller subblock (eg, using at least one small weight). That is, the soft buffer is used efficiently and flexibly. As a result, the blocking probability of the HARQ process of both the PCC and the at least one SCC is reduced, and the data transmitted to the PCC can be quickly recovered and executed. Thus, system throughput is increased and the UE can operate regularly without interruption or delay.

The goal of process 70 is to allow the UE to prepare a HARQ process for the PCC and at least one SCC, in different sized subblocks (and thus in different sized partitions) of the soft buffer so that the soft buffer is used efficiently and flexibly. Please note. The factor that the UE follows in determining a plurality of weights is not limited. The method on which the UE bases to split the soft buffer and prepare for the HARQ process is not limited either.

이고

이다. 그 후, UE는 지시에 따라 복수의 CC에 대응하는 복수의 가중치를 결정하고, 복수의 가중치에 따라 다음과 같이 소프트 버퍼를 복수의 서브블록으로 분할한다:In general, the soft buffer partition rule in a wireless communication system 40 composed of a CA is introduced as follows. First, the total number of soft channel bits of the UE (that is, the size of the soft buffer), N _soft is divided into N _C of subblocks for a CC configured dogs N _C according to any partition rule (for example: N _soft is configured CC Split equally for all). The tentative size of the subblock in terms of soft channel bits for the nth _C- th CC is defined as N ' _soft (n _C ),

ego

to be. Thereafter, the UE determines a plurality of weights corresponding to the plurality of CCs according to the indication, and partitions the soft buffer into a plurality of subblocks according to the plurality of weights as follows:

는 지시에 따른 n_C번째 CC에 대한 가중치이며, 0보다 큰 양의 값이다. 유의할 것은 PCC의 가중치는 SCC의 가중치와 같거나 그보다 크게 설정될 수 있다는 것이다. N_soft(n_C)는 n_C번째 CC에 대한 소프트 채널 비트의 측면에서의 서브블록의 크기이고, 가중치 w(n_C) 및 임시 크기 N'_soft(n_C)에 따라 결정된다. UE가 구성된 CC 각각에 대한 소프트 버퍼의 크기를 결정한 후, 구성된 CC 각각의 전송 블록에 대한 파티션의 크기는 다음과 같이 결정될 수 있다:here,

Is a weight for the n _C th CC according to the indication, and is a positive value greater than zero. Note that the weight of the PCC may be set equal to or greater than the weight of the SCC. N _soft (n _C ) is the size of the subblock in terms of soft channel bits for the n _C th CC, and is determined according to the weight w (n _C ) and the temporary size N ' _soft (n _C ). After the UE determines the size of the soft buffer for each configured CC, the size of the partition for each transport block of the configured CC may be determined as follows:

In the above equation, N _IR (n _c ) is the size of a partition for the transport block of the n _C th CC. N _soft (n _C ) is the size of the subblock in terms of soft channel bits for the n _C th CC. K _MIMO is the number of transport blocks that can be transmitted to a UE in one TTI per CC and is related to the MIMO used by the UE and the network. M _limit is a positive value. M _{DL _ HARQ} (n _c ) is the maximum number of DL HARQ processes for the n _C th CC and corresponds to the duplex mode and its configuration.

이므로, N_soft(1)은 N_soft(2)와 같거나 그보다 크다.For example, referring to FIG. 8, FIG. 8 is a schematic diagram of a soft buffer SB according to an example of the present invention. The UE consists of two CCs by the network and operates in FDD mode, one of the two CCs being the PCC and the other being the SCC. Since only one transport block can be transmitted to a UE in one TTI (ie, spatial multiplexing is not available), according to the present invention, the UE sets a soft buffer (SB) to two subblocks for each configured CC. Since it is divided into (SB_1 and SB_2), at most eight HARQ processes can be stored in each subblock. Accordingly, the UE may prepare HARQ processes for two CCs in subblocks SB_1 and SB_2, and each HARQ process is prepared in a corresponding partition. Specifically, the size of the soft buffer SB (eg, the number of soft channel bits) is N _soft . The sizes of the subblocks SB_1 and SB_2, which are N _soft (1) and N _soft (2), respectively, are the same, that is, N ' _soft (1) = N' _soft (2) = N _soft / 2. Subblocks SB_1 and SB_2 are used for the HARQ process of PCC and SCC, respectively. And, the sizes of subblocks SB_1 and SB_2 are modified as follows using weights w (1) = w _PCC and w (2) = (2-w _PCC ), respectively: N _soft (1) = N ' _soft ( 1)? W (1) and N _soft (2) = N ' _soft (2)? W (2), where

N _soft (1) is equal to or greater than N _soft (2).

As shown in FIG. 8, the subblock SB_1 is divided into eight partitions P801-P808, and the subblock SB_2 is divided into eight partitions P809-P816. The UE may determine the partition size N _IR (1) and N _IR (2) for each transport block of the configured CC according to equation 3. That is, the size of each partition P801-P808 is N _IR 1 and the size of each partition P809-P816 is N _IR 2. Thus, the more important HARQ process of PCC can be prepared in 8 partitions of large N _IR 1. At the same time, the HARQ process of the less important SCC can also be prepared in eight partitions of the small N _IR 2. Note that the above example shows a case where the soft block is first divided evenly into subblocks of the same size before applying weights to the subblocks (that is, N ' _soft (n ₁ ) = N' _soft (n _2). n ₁ ≠ n ₂ is the index of CC). However, the soft buffer can also be divided into subblocks of various sizes. That is, N ' _soft (n _C ) for the n _C th CC is arbitrary. Then, by applying the weight w (n _C ) to the subblock corresponding to the n _C th CC and using N _soft (n _C ) = N ' _soft (n _C )? W (n _C ), the size N _soft (n _C ) As a result, the blocking probability of the HARQ process of both PCC and SCC does not increase. Since a large (i.e. better coding performance) HARQ process can be stored in the soft buffer, the data and control information sent to the PCC are quickly recovered. System throughput is effectively increased by using a CA that is not affected by the inefficient use of soft buffers.

는 x보다 크지 않는 최대 정수이다. 다시 말해, 가중치 w_PCC는 Ratio_PCC 및 CC의 개수 N_c로 지시된다. 상세하게는, 지시는 UE에 의해 파라미터 Ratio_PCC 및 CC의 개수 N_c에 따라 생성된다. 또는, 지시는 네트워크에 의해 파라미터 Ratio_PCC 및 CC의 개수 N_c에 따라 생성되고, 그 후 지시는 네트워크에 의해 UE에 송신된다. 또한, 지시는 UE 및 네트워크 모두에 의해 파라미터 Ratio_PCC 및 CC의 개수 N_c(즉, 동일한 규칙)에 따라 생성될 수도 있다. 파라미터 Ratio_PCC는 다음과 같이 표현될 수 있다:Note that the factors that the weight for the PCC determines in determining are not limited. For example, referring to FIG. 9, FIG. 9 is a table 90 of weights w _PCC in accordance with an example of the present invention. The table 90 is preferably stored at the UE. In the table 90, the weight w _PCC is determined by the parameter Ratio _PCC and the number N _c of CCs,

Is the largest integer not greater than x. In other words, the weight w _PCC is indicated by the number N _c of Ratio _PCC and CC. In detail, the indication is generated by the UE according to the parameter ratio _PCC and the number N _c of CCs. Or, the indication is generated by the network according to the parameter ratio _PCC and the number N _c of CCs, and the indication is then transmitted by the network to the UE. In addition, the indication may be generated by both the UE and the network according to the number N _c of the parameter Ratio _PCC and CC (ie, the same rule). The parameter Ratio _PCC can be expressed as follows:

)는 양의 값이다. PCC에 대한 가중치 w_PCC가 결정된 후, n번째 SCC에 대한 가중치 w(n_c)는 다음과 같이 결정될 수 있다: w(n_c)=(N_C-w_PCC)/(N_C-1), 여기서 n_c∈ SCC의 인덱스이다. 따라서, CC 각각에 대한 파티션의 크기는 그에 따라 수정되거나 조정될 수 있다.In the above equation, BW (PCC) and BW (n _c ) are the bandwidths of the PCC and n _c th CCs, respectively, and r _ij (

) Is a positive value. After the weight w for _PCC has been determined, the weight w (n _c ) for the nth SCC may be determined as follows: w (n _c ) = (N _C -w _PCC ) / (N _C -1), Where n _c 인덱스 is the index of the SCC. Thus, the size of the partition for each CC can be modified or adjusted accordingly.

Note that the instructions (and thus weights) can be generated according to various factors such as design considerations or system requirements. For example, the indication (and thus the weight) may indicate the priority of the CC configured in the UE, the UE category of the UE, the number of NACKs transmitted by the UE, the average number of HARQ processes of the UE, the traffic load of the UE, the UE The number of CCs configured in the UE, the bandwidth of the CC configured in the UE, and the maximum number of layers supported by the UE may be determined, but is not limited thereto. That is, the indication (and thus the weight M _overbooking ) is generated according to the combination of parameters and variables described above (eg, by the UE or the network). In addition, the aforementioned indication (and thus weight) may be generated by the UE itself. Or, the indication is generated by the network and sent to the UE via signaling (eg, radio resource control (RRC) signaling) by the network. In addition, the indication can be generated according to the same rules by both the UE and the network, reducing the overhead of signaling. In addition, it is not limited when a soft buffer is divided into a some partition with respect to a some CC. For example, the soft buffer may be partitioned after the PCC of the CC is reconstructed. That is, an indication to determine the weight is generated after the PCC is reconstructed. Alternatively, the soft buffer may be divided after the number of CCs is changed. That is, an instruction for determining the weight after the number of CCs is changed is generated. In addition, the CC mentioned in the above example is preferably called a DL CC because the HARQ process stored in the UE corresponds to a packet transmitted in the DL.

In addition, the process 70 and examples described above can be implemented in a network. For example, the network may determine the weight according to the indication and transmit the weight to the UE, so that the UE may determine the size of the subblock according to the weight. Or, the network may also determine the size of the subblock according to the weight and send the size to the UE, so that the UE may divide the soft buffer into subblocks according to the size of the subblock. In addition, since the same indication is generated by the UE according to the same rule, the network may not need to transmit the weight or the size of the subblock to the UE. Accordingly, the UE may determine the weight and determine the size of the subblock according to the weight to divide the soft buffer into subblocks according to the size of the subblock.

Referring to FIG. 10, FIG. 10 is a flow diagram of a process 100 in accordance with an example of the present invention. Process 100 is used to process the soft buffer of the UE, in the UE and network shown in FIG. The UE is composed of a plurality of CCs by a network, the plurality of CCs comprising a primary CC (PCC) and at least one secondary CC (SCC). Process 100 may be compiled into program code 514 and includes the following steps:

Step 1000: Start the process 100.

Step 1002: Split at least one subblock of the soft buffer into a plurality of partitions, the number of the plurality of partitions being determined according to the instruction.

Step 1004: Prepare a plurality of HARQ processes for a plurality of CCs in a plurality of partitions.

Step 1008: The process 100 ends.

According to process 100, the UE divides at least one subblock of the soft buffer into a plurality of partitions, the number of the plurality of partitions being determined according to the indication. Thereafter, the UE prepares a plurality of HARQ processes for the plurality of CCs in the plurality of partitions. In other words, the UE divides one or more subblocks of the soft buffer into various numbers of partitions to prepare (eg, store) a plurality of HARQ processes for a plurality of CCs in the partition. For example, the UE may reduce the blocking probability of the HARQ process by dividing the soft buffer into more partitions in order to prepare more small HARQ processes in the partition. Alternatively, the UE may divide the soft buffer into fewer partitions to prepare fewer HARQ processes in the partition, thereby improving the coding performance of the HARQ process. In other words, the soft buffer is used efficiently and flexibly. As a result, a better tradeoff between blocking probability and coding performance can be achieved. Thus, system throughput is increased and the UE can operate regularly without interruption or delay.

The goal of the process 100 is to allow the UE to divide one or more subblocks of the soft buffer into various numbers of partitions and to prepare a plurality of HARQ processes for a plurality of CCs in that partition, so that the soft buffer is efficiently and flexibly utilized. Please note. The factor that the UE determines for the number of partitions is not limited. The method on which the UE bases to split the soft buffer and prepare for the HARQ process is not limited either.

For example, the soft buffer of the UE can be partitioned directly into more partitions so that more HARQ processes can be stored in the soft buffer. In other words, the soft buffer is not divided into multiple subblocks. That is, the soft buffer is divided into only one subblock. Referring to FIG. 11, FIG. 11 is a schematic diagram of a soft buffer SB according to an example of the present invention. The soft buffer SB may be divided into various numbers of partitions as shown in FIG. 11. The number of CCs configured in the UE is not limited. In detail, the soft buffer SB of size N _soft is divided into a plurality of partitions, and the size of each partition is N _IR according to the following equation:

로 설정된다. 도 11에 도시된 바와 같이, 모든 CC의 DL HARQ 프로세스는 고정된 M_overbooking에 대해 소프트 버퍼(SBa)의 모든 파티션을 공유한다. 즉, PCC 및 SCC에 사용된 파티션의 크기는 동일하다(즉, N_IR). 가중치 M_overbooking를 결정할 때 DL HARQ 프로세스의 코딩 성능과 차단 확률 간의 트래드오프가 생길 수 있다. 즉, 최악의 코딩 성능의 비용에서는 파티션이 많을수록 차단 확률은 낮아지고, 최고의 차단 확률의 비용에서는 파티션이 적을수록 코딩 성능이 좋아진다.In the above equation, K _MIMO is the number of transport blocks that can be transmitted to the UE with one TTI per CC and is related to the MIMO used by the UE and the network. In general, when spatial multiplexing of n spatial streams is configured in the UE, K _MIMO is set to n and is a positive value. M _overbooking is a weight included in an instruction for controlling the number of partitions and is a positive value. M _limit is a positive value, for example M _limit = 8. M ' _{DL _ HARQ} is the maximum number of DL HARQ processes per serving cell when the configured CC is configured in the same duplex mode and configuration. Meanwhile, when the UE operates in the TDD mode, M ' _{DL _ HARQ} is the maximum number of DL HARQ processes for the PCC when at least one configured SCC is configured with a different UL / DL configuration. Thus, when the UE operates in FDD mode and does not support spatial multiplexing, the soft buffer SBa is divided into 8 M _overbooking partitions, and the sizes of the partitions are the same when using fixed M _overbooking . That is, when the weight M _overbooking is set to 1, 2, 3, 4, and 5, when spatial multiplexing is not supported by the UE, the soft buffers SBa are 8, 16, 24, 32, and 40 pieces. Each partition is divided into partitions. In this case, the size of each partition

. As shown in FIG. 11, the DL HARQ process of all CCs shares all partitions of the soft buffer SBa for fixed M _overbooking . That is, the partitions used for PCC and SCC are the same size (ie N _IR ). In determining the weight M _overbooking , there may be a tradeoff between the coding performance of the DL HARQ process and the blocking probability. That is, at the cost of worst coding performance, the more partitions, the lower the blocking probability, and at the cost of the best blocking probability, the smaller the partition, the better the coding performance.

)는 양의 값이다. 테이블(120)에 도시된 바와 같이, 가중치 M_overbooking는 CC의 개수에 따라 결정된다. 예를 들면, UE에 4개의 CC가 구성되는 경우, 가중치 M_overbooking는 f₄로 설정된다. 한편, 가중치 M_overbooking는 CC의 개수 및 UE의 UE 카테고리 양자에 따라 결정될 수도 있다. 도 13을 참조하면, 도 13은 본 발명의 예에 따른 CC의 개수 및 UE의 UE 카테고리에 관련된 가중치 M_overbooking의 테이블(122)이며, f_{i ,j}(

)는 양의 값이다. 예를 들면, UE 카테고리가 5개이고 3개의 CC가 UE에 구성되어 있는 경우, 가중치 M_overbooking는 f_{5 ,3}으로 설정된다. 또, 가중치 M_overbooking는 UE의 UE 카테고리 및 UE에서 지원하는 계층의 최대 개수 양자에 따라 결정될 수 있다. 도 14를 참조하면, 도 14는 본 발명의 예에 따른 UE의 UE 카테고리 및 UE에서 지원하는 계층의 최대 개수와 관련된 가중치 M_overbooking의 테이블(124)이며, f_i,j(

)는 양의 값이다. 예를 들면, UE 카테고리가 7개이고 UE에서 지원하는 계층의 최대 개수가 4개인 경우, 가중치 M_overbooking는 f_{7 ,4}로 설정된다. Note that the indication (and thus the weight M _overbooking ) can be generated according to various factors such as design considerations or system requirements. For example, the weighted M _overbooking is the priority of the CC configured in the UE, the UE category of the UE, the number of NACKs transmitted by the UE, the average number of HARQ processes of the UE, the traffic load of the UE, the number of CCs configured in the UE, It may be generated according to a combination of the bandwidth of the CC configured in the UE and the maximum number of layers supported by the UE, but is not limited thereto. That is, the indication (and thus the weight M _overbooking ) is generated according to the combination of parameters and variables described above (eg, by the UE or the network). 12, FIG. 12 is a table of weights M _overbooking related to the number of CCs according to an example of the present invention, and f _j (

) Is a positive value. As shown in table 120, the weight M _overbooking is determined according to the number of CCs. For example, if four CCs are configured in the UE, the weight M _overbooking is set to f ₄ . Meanwhile, the weight M _overbooking may be determined according to both the number of CCs and the UE category of the UE. Referring to FIG. 13, FIG. 13 is a table 122 of weights M _overbooking related to the number of CCs and a UE category of a UE according to an example of the present invention, wherein f _{i , j} (

) Is a positive value. For example, if there are five UE categories and three CCs are configured in the UE, the weight M _overbooking is set to f _{5 , 3} . In addition, the weight M _overbooking may be determined according to both the UE category of the UE and the maximum number of layers supported by the UE. Referring to FIG. 14, FIG. 14 is a table 124 of weights M _overbooking associated with the UE category of the UE and the maximum number of layers supported by the UE according to an example of the present invention, and f _{i, j} (

) Is a positive value. For example, if there are seven UE categories and the maximum number of layers supported by the UE is four, the weight M _overbooking is set to f _{7 , 4} .

In the above example, the present invention applies to all CCs configured in the UE. However, the present invention can also be applied to a subset of CCs configured in the UE. 15, FIG. 15 is a schematic diagram of a soft buffer SBb according to an example of the present invention. In this example, five CCs including PCC (C ₁ ) and SCC (C ₂ -C ₅ ) are configured in the UE. Specifically, the weight M _overbooking corresponding to the PCC (C ₁₎ is set to 1, the weight M _overbooking corresponding to the SCC (C ₂ -C ₅₎ is set to 3. That is, eight partitions P1301-P1308 that are not changed as shown by the soft buffer SBb_1 in FIG. 15 are seen in the PCC C ₁ , and the size of each partition is N _IR (1). In addition, as shown in the soft buffer SBb_2 in FIG. 15, 24 partitions P1301a-P1324a are seen in the SCC (C ₂ -C ₅ ), and the size of each partition is N _IR (2), that is, N _IR ( 1) = 3N _IR (2). In addition, the HARQ processes of the PCC C ₁ and the SCC C ₂ -C ₅ may be prepared in the soft buffer SBb according to the corresponding partitions shown by the soft buffer SBb_2 and the soft buffer SBb_2. . An example of preparing HARQ for a CC will be described below. At time t1, the UE should prepare (store) the HARQ process of PCC C ₁ . Since the soft buffer SBb is empty, the UE prepares a HARQ process of the PCC C ₁ in the partitions P1301 (ie, partitions P1301a-P1303a). At time t2, the UE must prepare for the HARQ process of SCC C ₅ , and the UE continues to prepare for the HARQ process of SCC C ₅ in partition P1304a. At time t3, the UE must again prepare for another HARQ process of PCC C ₁ . Since the size of the partition seen in PCC C ₁ is N _IR 1, the UE prepares another HARQ process of PCC C ₁ in partition P1303 (ie, partitions P1307a-P1309a). In addition, at times t4 and t5, the UE must prepare for the HARQ process of SCC (C ₃ ) and SCC (C ₄ ). The UE prepares HARQ processes of SCC (C ₃ ) and SCC (C ₄ ) in partitions P1305a and P1306a, respectively. Thus, in addition to low blocking probabilities and good coding performance, the present invention can flexibly use the soft buffer by dividing the soft buffer into smaller partitions for only a portion of the CC configured in the UE.

Meanwhile, the present invention may also be applied to some of the soft buffers of the UE. That is, only a part of the soft buffer is divided into partitions of various sizes and amounts according to weights, and the other part of the soft buffer is divided into eight partitions according to the prior art. For example, referring to FIG. 16, FIG. 16 is a schematic diagram of a soft buffer SBc according to an example of the present invention.

The soft buffer SBc is used for the HARQ process of CC (C ₁ -C ₅ ), and is first divided into two subblocks SBc_1 and SBc_2. Subblock SBc_1 is used for CC (C ₁ , C ₂ ), and subblock SBc_2 is used for CC (C ₃ -C ₅ ). The size of subblock SBc_1 and subblock SBc_2 _{, which} are N _{soft , sb} (1) and N _{soft , sb} (2), respectively, may be determined according to different design considerations or system requirements (eg, instructions), It is not limited. Thereafter, the subblock SBc_1 is further divided into various numbers of partitions. In other words, the method on which the subblock SBc_1 is further divided is not limited. Embodiments and methods described above can be applied directly. For example, the method illustrated in FIG. 8 may be applied to the subblock SBc_1 shown in FIG. 16 by replacing N _soft of FIG. 8 with N _{soft , sb} (1) of FIG. 16. Similarly, sub-block (SBc_1) can be further divided into N _soft (1) and two sub-blocks and SBc_11 SBc_12 size of N _soft (2), respectively. Subblocks SBc_11 and SBc_12 are divided into partitions P1401-1416, each of partitions P1401-1408 is N _IR (1), and each of partitions P1409-1416 is N _IR (2). The subblock SBc_2 is divided into eight partitions according to the prior art, which is not described here for the sake of simplicity. In sum, those skilled in the art can readily combine, change, or modify the processes 70, 100, and examples described above. Thus, in addition to lower blocking probabilities and better coding performance, the present invention can also flexibly utilize soft buffers by dividing only a portion of the soft buffer into smaller partitions.

In addition, the above-described instructions (and thus weights) may be generated by the UE itself. Or, the indication is generated by the network and sent by the network to the UE via signaling (eg, radio resource control (RRC) signaling). In addition, the indication may be generated at both the UE and the network according to the same rules to reduce the overhead of signaling. For example, the soft buffer may be partitioned after the PCC of the CC is reconstructed. That is, an indication that can determine the weight is generated after the PCC is reconstructed. Alternatively, the soft buffer may be divided after the number of CCs is changed. In other words. An indication to determine the weight is generated after the number of CCs is changed. In addition, the CC mentioned in the above examples is preferably called a DL CC because the HARQ process stored in the UE corresponds to a packet transmitted in the DL.

Again, the process 100 and examples described above can be implemented in a network. For example, the network may determine the number of partitions according to the indication and transmit the partition information (eg, the number) to the UE, so that the UE may divide the soft buffer into partitions according to the information. In addition, since the same indication is generated at the UE according to the same rule, the network may not need to transmit information to the UE. Accordingly, the UE may determine the number and divide the soft buffer into subblocks according to the number.

Note that the above steps of the process including the proposed steps may be implemented by hardware, firmware known as a combination of hardware instructions and computer instructions and data residing as read-only software on the hardware device, or an electronic system. . Examples of hardware may include analog, digital, and mixed circuits known as microcircuits, microchips, or silicon chips. Examples of electronic systems may include a system on chip (SOC), a system in package (SiP), a computer on module (COM), and the communication device 30.

In short, the present invention provides a method for processing a soft buffer of a UE composed of multiple CCs in a wireless communication system. The blocking probability of the HARQ process of the CC is reduced. In addition, data transmitted on the PCC can be quickly recovered and executed. Therefore, the system processing direction is increased, and the UE can operate regularly without interruption or delay.

Claims (26)

A soft buffer processing method for processing a soft buffer of a mobile device in a wireless communication system,
The mobile device is composed of a plurality of element carriers (hereinafter referred to as CCs) by a network of the wireless communication system, wherein the plurality of CCs are a main CC (hereinafter referred to as PCC) and one or more secondary CCs (hereinafter referred to as SCC). ),
The method comprises:
Determining a plurality of weights corresponding to the plurality of CCs according to the instruction;
Determining a plurality of sizes of the plurality of subblocks according to the plurality of weights; And
The soft buffer is divided into the plurality of subblocks according to the plurality of sizes of the plurality of subblocks, and a plurality of hybrid automatic retransmission requests (hereinafter, referred to as HARQ) processes for the plurality of CCs are provided to the plurality of subblocks. Steps to prepare
Soft buffer processing method comprising a. A soft buffer processing method for processing a soft buffer of a mobile device in a wireless communication system for a network of a wireless communication system,
The mobile device is comprised of a plurality of CCs by the network, the plurality of CCs comprising a PCC and one or more SCCs,
The method comprises:
Determining a plurality of weights corresponding to the plurality of CCs according to the instruction; And
Determining a plurality of sizes of the plurality of subblocks according to the plurality of weights, and dividing the soft buffer into the plurality of subblocks according to the plurality of sizes.
Soft buffer processing method comprising a. The method according to claim 1 or 2,
Soft buffer processing, wherein a weight corresponding to the PCC is greater than one or more weights corresponding to the one or more SCCs, or a size of a subblock for the PCC is greater than one or more sizes of one or more subblocks for the one or more SCCs Way. The method according to claim 1 or 2,
The indication includes a plurality of priorities of the plurality of CCs, a user device (hereinafter referred to as a UE), a category of the mobile device, a number of negative acknowledgments (hereinafter referred to as NACKs) of the mobile device, and the mobile device. The soft buffer processing method is generated according to a combination of an average number of HARQ processes, a traffic load of the mobile device, the number of the plurality of CCs, the bandwidth of the plurality of CCs and the maximum number of layers supported by the mobile device. . The method according to claim 1 or 2,
And the plurality of weights are a plurality of positive values. The method according to claim 1 or 2,
Determining a plurality of weights corresponding to the plurality of CCs according to the instruction,
After the PCC is reconstructed, determining a plurality of weights corresponding to the plurality of CCs according to the indication; or
And after the number of the plurality of CCs is changed, determining a plurality of weights corresponding to the plurality of CCs according to the instruction. The method according to claim 1 or 2,
And the plurality of CCs are downlink (hereinafter referred to as DL) CCs. The method of claim 1,
The indication is generated by the mobile device; The indication is generated by the mobile device and the network according to the same rule; And the indication is generated by the network and transmitted by the network to the mobile device via signaling. The method of claim 2,
And the indication is generated by the mobile device and the network according to the same rule. 10. The method of claim 9,
The mobile device determines a plurality of weights corresponding to the plurality of CCs according to the indication, determines a plurality of sizes of the plurality of subblocks according to the plurality of weights, and sets the soft buffer to the plurality of sizes. And dividing the data into the plurality of subblocks. The method of claim 2,
Transmitting the plurality of weights to the mobile device, such that the mobile device determines a plurality of sizes of the plurality of subblocks according to the plurality of weights. The method of claim 2,
Transmitting the plurality of sizes of the plurality of subblocks to the mobile device. A soft buffer processing method for processing a soft buffer of a mobile device in a wireless communication system,
The mobile device is composed of a plurality of component carriers (hereinafter referred to as CC) by the network of the wireless communication system,
The method comprises:
Dividing one or more subblocks of the soft buffer into a plurality of partitions, the number of the plurality of partitions being determined according to an instruction; And
Preparing a plurality of hybrid automatic retransmission request (hereinafter referred to as HARQ) processes for a plurality of CCs in the plurality of partitions;
Soft buffer processing method comprising a. A soft buffer processing method for processing a soft buffer of a mobile device in a wireless communication system for a network of a wireless communication system,
The mobile device is composed of a plurality of CCs by the network,
The method comprises:
Determining the number of partitions in accordance with the instructions; And
Dividing one or more subblocks of the soft buffer into a plurality of partitions according to the number of the plurality of partitions
Soft buffer processing method comprising a. The method according to claim 13 or 14,
Dividing one or more subblocks of the soft buffer into a plurality of partitions, wherein the number of the plurality of partitions is determined according to an instruction,
A soft buffer processing method comprising dividing the one or more subblocks according to the following equation:

Wherein N _soft is the size of one of the one or more subblocks; N _IR is the size of each of the plurality of partitions; K _MIMO is associated with multiple input multiple output (hereinafter referred to as MIMO) used by the mobile device and the network; M _overbooking is a weight included in the indication for controlling the number of the plurality of partitions, and is a positive value; M _limit is a positive value; M _{_ DL HARQ} is a maximum number of HARQ processes for a plurality of downlink CC; min (x, y) returns the smaller of x and y;

Is the largest integer not greater than x. The method according to claim 13 or 14,
The indication includes a plurality of priorities of the plurality of CCs, a user device (hereinafter referred to as a UE), a category of the mobile device, a number of negative acknowledgments (hereinafter referred to as NACKs) of the mobile device, and the mobile device. The soft buffer processing method is generated according to a combination of an average number of HARQ processes, a traffic load of the mobile device, the number of the plurality of CCs, the bandwidth of the plurality of CCs and the maximum number of layers supported by the mobile device. . The method according to claim 13 or 14,
Dividing one or more subblocks of the soft buffer into a plurality of partitions, wherein the number of the plurality of partitions is determined according to an instruction,
After the main CCs (hereinafter referred to as PCCs) of the plurality of CCs are reconstructed, dividing one or more subblocks of the soft buffer into a plurality of partitions, wherein the number of the plurality of partitions is determined according to an instruction; or
And after the number of the plurality of CCs is changed, dividing one or more subblocks of the soft buffer into a plurality of partitions, wherein the number of the plurality of partitions is determined according to an instruction. The method according to claim 13 or 14,
The plurality of CCs are all CCs configured in the mobile device; The plurality of CCs is part of the CCs configured in the mobile device; And the plurality of CCs is a downlink (hereinafter, referred to as DL) CC of a CC. The method according to claim 13 or 14,
And the soft buffer is a full soft buffer of the mobile device or part of the full soft buffer of the mobile device. The method according to claim 13 or 14,
And dividing the soft buffer into one or more subblocks according to the instructions. The method according to claim 13 or 14,
The number of the one or more subblocks is one,
Dividing one or more subblocks of the soft buffer into a plurality of partitions, wherein the number of the plurality of partitions is determined according to an instruction,
Dividing the soft buffer into the plurality of partitions, the number of the plurality of partitions being determined according to an instruction. The method of claim 13,
The indication is generated by the mobile device; The indication is generated by the mobile device and the network according to the same rule; And the indication is generated by the network and transmitted by the network to the mobile device via signaling. 15. The method of claim 14,
And transmitting information of the plurality of partitions to the mobile device such that the mobile device prepares a plurality of HARQ processes for the plurality of CCs in the plurality of partitions. 15. The method of claim 14,
And the indication is generated by the mobile device and the network according to the same rule. 25. The method of claim 24,
And the mobile device determines the number of the plurality of partitions according to the indication, and divides one or more subblocks of the soft buffer into the plurality of partitions according to the number of the plurality of partitions. A wireless communication system comprising one or more mobile devices implementing the method of claim 1 or 13 or comprising one or more mobile devices implementing the method of claim 2.

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