JP6899460B2 - Short latency fast retransmission trigger - Google Patents

Description

The present disclosure relates to a method of operating a transmission protocol for uplink data packet transmission in a communication system. The disclosure also provides user equipment and base stations involved in the methods described herein.

[Long Term Evolution (LTE)]
Third-generation mobile systems (3G) based on WCDMA® wireless access technology are widely deployed around the world. The first step in improving or evolving this technology is also referred to as High-Speed Downlink Packet Access (HSDPA) and High-Speed Uplink Packet Access (HSUPA). ) Will inevitably accompany the provision of competitively superior wireless access technology.

In preparation for further increase in user demand, 3GPP has introduced a new mobile communication system called Long Term Evolution (LTE) in order to secure an advantage over new wireless access technologies. LTE is designed to meet carrier requirements for the next decade for high-speed data and media transfers as well as high-capacity voice support. Being able to provide high bit rates is a major measure of LTE.

The Work Item (WI) specification for Long Term Evolution (LTE), called Evolved UMTS Terrestrial Radio Access (UTRA) and UMTS Terrestrial Radio Access Network (UTRAN), is the 8th edition (WI). It is completed as LTE Rel.8). LTE systems represent efficient packet-based radio access and radio access networks that provide low latency, low cost, fully IP-based functionality. In LTE, expandable plurals such as 1.4, 3.0, 5.0, 10.0, 15.0, and 20.0 MHz for flexible system placement using a given spectrum. Transmission bandwidth is specified. In downlink, orthogonal frequency division multiplexing (OFDM) based radios due to their inherent immunity to multipath interference (MPI) due to low symbol rates, the use of cyclic prefixes (CPs), and their affinity for different transmit bandwidth configurations. Access was adopted. In the uplink, considering the limitation of transmission power of user equipment (UE: User Equipment), the provision of a wide range of service areas was prioritized over the improvement of peak data rate, so single carrier frequency division multiple access (SC). -FDMA) -based wireless access was adopted. LTE Rel. On 8/9, many major packet radio access technologies, including multi-input, multi-output (MIMO) channel transmission technologies, have been adopted to realize highly efficient control signaling structures.

[LTE architecture]
The overall LTE architecture is shown in Figure 1. The E-UTRAN consists of an eNodeB and provides an E-UTRA user plane (PDCP / RLC / MAC / PHY) and control plane (RRC) protocol termination towards the user equipment (UE). The eNodeB (eNB) hosts physical (PHY), media access control (MAC), wireless link control (RLC), and packet data control protocol (PDCP) layers, including user plane header compression and encryption capabilities. It also provides a radio resource control (RRC) function corresponding to the control plane. eNodeB provides radio resource management, admission control, scheduling, negotiated uplink quality of service (QoS) enforcement, cell information broadcasting, user and control plane data encryption / decryption, and downlink / uplink user plane packets. Performs many functions such as header compression / decompression. The eNodeBs are connected to each other by an X2 interface.

The eNodeB is also connected to the EPC (Evolved Packet Core) by the S1 interface. More specifically, the eNodeB is connected to the MME (mobility management entity) by S1-MME and to the serving gateway (SGW) by S1-U. It is connected. The S1 interface supports a many-to-many relationship between the MME / serving gateway and the eNodeB. The SGW acts as a mobility anchor for the user plane during eNodeB-to-eNodeB handovers and as a mobility anchor between LTE and other 3GPP technologies (terminating the S4 interface and terminating the 2G / 3G system and PDN GW). Routes and forwards user data packets (while relaying traffic to and from). For idle user equipment, the SGW terminates the downlink data path and triggers paging when the downlink data arrives at the user equipment. The SGW manages and stores the context of the user device (for example, the parameter of the IP bearer service) or the routing information inside the network. It also performs duplication of user traffic in the case of lawful intercept.

The MME is the main control node of the LTE access network. Responsible for tracking and paging procedures for idle mode user equipment, including retransmissions. The MME is involved in the bearer enable / disable process and is responsible for selecting the SGW of the user equipment during initial connection and during LTE intra-LTE handover with relocation of core network (CN) nodes. It is also responsible for user authentication (by interacting with HSS). In MME, non-access layer (NAS) signaling is terminated, and it is also responsible for generating temporary identification information and distributing it to user devices. It confirms the authentication of the user equipment, stays in the service provider's public land mobile network (PLMN), and enforces roaming restrictions on the user equipment. The MME is the end point in the network for the encryption / integrity protection of NAS signaling and handles the primary management of security. MME also supports lawful intercept of signaling. The MME also provides a control plane function for mobility between LTE and a 2G / 3G access network with the S3 interface terminated from SGSN to MME. The MME also terminates the S6a interface towards the home HSS to roam the user equipment.

[Component carrier structure in LTE]
The downlink component carriers of the 3GPP LTE system are subdivided into so-called subframes in the time-frequency domain. In 3GPP LTE, as shown in FIG. 2, each subframe is divided into two downlink slots, and the first downlink slot includes a control channel area (PDCCH area) in the first OFDM symbol. Each subframe consists of a given number of OFDM symbols in the time domain (12 or 14 OFDM symbols in 3GPP LTE (Rel.8)), with each OFDM symbol covering the entire bandwidth of the component carrier. Therefore, each OFDM symbol consists of a large number of modulation symbols transmitted on each subcarrier. In LTE, the transmission signal of each slot is described by a resource grid of ^{N DL} _RB N ^RB _SC subcarriers and N ^DL _{symb OFDM symbols.} N ^DL _RB is the number of resource blocks in the bandwidth. The quantity N ^DL _RB is determined by the downlink transmission bandwidth set in the cell and satisfies ^{N min, DL} _RB ≤ N ^DL _RB ≤ N ^{max, DL} _RB. Here, N ^{min, DL} _RB = 6 and N ^{max, DL} _RB = 110 are the minimum and maximum downlink bandwidths, respectively, and the specifications of the current version correspond to them. ^NRB _SC is the number of subcarriers in one resource block. For normal cyclic prefix sub-frame ^structure, the _{N RB} SC = 12 and ^N _{DL symb} = 7.

For example, assuming a multi-carrier communication system that employs OFDM or the like used in 3GPP long-term evolution (LTE), the minimum unit of resources that can be allocated by the scheduler is one "resource block". As illustrated in FIG. 2, the physical resource block (PRB) is a continuous OFDM symbol (for example, 7 OFDM symbols) in the time domain and a continuous subcarrier (for example, in the case of a component carrier) in the frequency domain. It is defined as 12 subcarriers). Therefore, in 3GPP LTE (Rel.8), the physical resource block consists of one slot in the time domain and resource elements corresponding to 180 kHz in the frequency domain (for details of the downlink resource grid, for example, http: // www. .3GPP TS 36.211 "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Releasure 8)" available at 3GPP.org (Current Edition 13.0.0, Section 2.0.0, 6. It can be referred to, but is incorporated herein by reference).

Since one subframe consists of two slots, there are 14 OFDM symbols in the subframe when the so-called "normal" CP (Circuit Prefix) is used, and when the so-called "extended" CP is used. There are 12 OFDM symbols in the subframe. For convenience of terminology, time-frequency resources equivalent to the same continuous subcarrier over the entire subframe will be referred to as "resource block pairs" or equivalent "RB pairs" or "PRB pairs".

The term "component carrier" refers to a combination of multiple resource blocks in the frequency domain. In future versions of LTE, the term "component carrier" will no longer be used. Alternatively, the terminology is changed to "cell", which represents a combination of downlink resources and optionally uplink resources. The linkage between the carrier frequency of the downlink resource and the carrier frequency of the uplink resource is specified in the system information transmitted on the downlink resource.

Similar assumptions about the component carrier structure apply to the successor.

[Carrier aggregation in LTE-A to support wider bandwidth]
At the World Radiocommunication Conference 2007 (WRC-07), the frequency spectrum of IMT Advance was determined. Although the entire frequency spectrum of IMT Advance has been determined, the actual available frequency bandwidth will vary by region or country. However, following the general determination of available frequency spectra, the standardization of wireless interfaces has begun in the 3rd Generation Partnership Project (3GPP). At the 3GPP TSG RAN # 39 meeting, the discussion items on "Further progress of E-UTRA (LTE advance)" were approved. This consideration covers the technical factors to consider regarding the evolution of E-UTRA, such as the satisfaction of requirements for IMT Advance.

The bandwidth supported by the LTE advance system is 100 MHz. On the other hand, the LTE system can only support 20 MHz. Today, the lack of radio spectrum has become a bottleneck in the development of wireless networks, and as a result, it is difficult to find a sufficiently wide spectrum band for LTE advanced systems. As a result, finding a way to obtain a wider radio spectrum band is an urgent task, and the possible answer is the carrier aggregation function.

In carrier aggregation, two or more component carriers are aggregated to accommodate a wider transmission bandwidth of up to 100 MHz. Multiple cells in the LTE system are aggregated into one wider channel in the LTE advanced system, which is wide enough for 100 MHz, even if these cells in the LTE are in different frequency bands.

At least the bandwidth of the component carrier is LTE Rel. If the supported bandwidth of 8/9 cells is not exceeded, LTE Rel. All component carriers can be configured to be 8/9 compliant. All component carriers aggregated by user equipment are not necessarily Rel. It does not have to be 8/9 compliant. Rel. 8/9 Existing mechanisms (eg, barring) may be used to prevent the user equipment from staying in the component carrier.

The user equipment may simultaneously receive or transmit on one or more component carriers (corresponding to multiple serving cells), depending on its capabilities. LTE-A Rel. With the ability to receive and / or transmit carrier aggregation. The 10-user device can simultaneously receive and / or transmit on a plurality of serving cells. On the other hand, LTE Rel. The 8/9 user device has a component carrier structure of Rel. Assuming that the 8/9 specification is followed, reception and transmission can be performed only on a single serving cell.

Carrier aggregation is addressed for both continuous and discontinuous component carriers, each limited to a maximum of 110 resource blocks in the frequency domain (using 3GPP LTE (Rel. 8/9) numerology).

3GPP LTE-A (Rel.10) compliant user equipment to aggregate different numbers of component carriers and potentially different bandwidths from the same eNodeB (base station) on the uplink and downlink. Can be set. The number of downlink component carriers that can be configured depends on the downlink aggregation capability of the UE. Conversely, the number of uplink component carriers that can be configured depends on the uplink aggregation capability of the UE. Currently, more uplink component carriers than downlink component carriers may not be able to configure mobile terminals. In a typical TDD arrangement, the number of component carriers on the uplink and downlink and the bandwidth of each component carrier are the same. Component carriers from the same eNodeB do not have to provide the same service area.

The spacing between the center frequencies of the continuously aggregated component carriers shall be a multiple of 300 kHz. This is to match the 100 kHz frequency raster of 3GPP LTE (Rel. 8/9) and at the same time maintain the orthogonality of the subcarriers at 15 kHz intervals. Depending on the aggregation scenario, a small number of unused subcarriers can be inserted between successive component carriers to facilitate n × 300 kHz intervals.

The nature of multi-carrier aggregation only appears up to the MAC layer. For both uplink and downlink, MAC is required to have one HARQ entity for each aggregated component carrier. For one component carrier, there is at most one transport block (if there is no SU-MIMO on the uplink). The transport block and its potential HARQ retransmissions need to be mapped on the same component carrier.

When carrier aggregation is set, there is only one RRC connection between the mobile terminal and the network. In establishing / reestablishing the RRC connection, LTE Rel. Similar to 8/9, one cell provides security inputs (one ECGI, one PCI, and one ARFCN) and non-access layer mobility information (eg, TAI). After establishing / reestablishing the RRC connection, the component carrier corresponding to the cell is referred to as the downlink primary cell (PCell). There is always only one downlink PCell (DL PCell) and one uplink PCell (UL PCell) for one user device in the connected state. In the set set of component carriers, the other cells are referred to as secondary cells (SCell), and the carriers of the SCell are the downlink secondary component carrier (DL SCC) and the uplink secondary component carrier (UL SCC). .. Up to 5 serving cells including PCell can be set for one UE.

[MAC layer / entity, RRC layer, physical layer]
The LTE Layer 2 User Plane / Control Plane Protocol Stack includes four sublayers: RRC, PDCP, RLC, and MAC. The media access control (MAC) layer is the lowest sublayer of the Layer 2 architecture of the LTE radio protocol stack and is defined, for example, by the 3GPP technical standard TS 36.321 (current version 13.0.0). Connections to the physical layer below it are via transport channels, and connections to the RLC layer above it are via logical channels. Therefore, the MAC layer performs multiplexing and demultiplexing of logical and transport channels. The transmitting MAC layer constitutes a MAC PDU known as a transport block from the MAC SDU received through the logical channel, and the receiving MAC layer restores the MAC SDU from the MAC PDU received through the transport channel.

The MAC layer provides RLC layer data transfer services through logical channels (see Sections 5.4 and 5.3 of TS 36.321, which are incorporated herein by reference), which are incorporated herein by reference. The logical channel is a control logical channel that carries control data (eg, RRC signaling) or a traffic logical channel that carries user plane data. Data from the MAC layer, on the other hand, is exchanged with the physical layer through transport channels classified as downlinks or uplinks. The data is multiplexed into transport channels depending on the method of wireless transmission.

The physical layer is responsible for the actual wireless transmission of data and control information. That is, the physical layer wirelessly carries all the information from the MAC transport channel on the transmitting side. Key functions performed by the physical layer include encoding and modulation, link adaptation (AMC), power control, cell search (for initial synchronization and handover), and the RRC layer (inside the LTE system and system). Other measurements (between) can be mentioned. The physical layer performs transmission based on transmission parameters such as modulation scheme, coding rate (ie, modulation / coding scheme (MCS)), number of physical resource blocks, and the like. Details regarding the function of the physical layer can be found in 3GPP Technical Standard 36.213 (current version 13.0.0), which is incorporated herein by reference.

The radio resource control (RRC) layer controls the communication between the UE and the eNB on the radio interface and the mobility of the UE moving through multiple cells. The RRC protocol also supports the transfer of NAS information. In the case of the UE of RRC_IDLE, the RRC also supports notification from the incoming call network. RRC connection control includes paging, measurement setup and reporting, radio resource configuration, initial security enablement, and establishment of signaling radio bearers (SRBs) and radio bearers carrying user data (data radio bearer DRBs). Covers all procedures related to establishing, modifying, and releasing RRC connections.

The wireless link control (RLC) sublayer mainly includes ARQ function and supports data segmentation and concatenation. That is, the RLC layer performs framing of the RLC SDU to the size specified by the MAC layer. The latter two minimize protocol overhead independently of the data rate. The RLC layer is connected to the MAC layer via a logical channel. Each logical channel carries a different type of traffic. The upper layer of the RLC layer is usually a PDCP layer, but in some cases it is an RRC layer. That is, RRC messages transmitted on the logical channels BCCH (broadcast control channel), PCCH (paging control channel), and CCCH (common control channel) do not require security protection, so they bypass the PDCP layer and directly RLC. Head to the layer. The main services and functions of the RLC sublayer are
Transfer of higher layer PDUs that support AM, UM, or TM data transfer,
Error correction through ARQ,
Divided according to TB size,
Subdivision as needed (eg when changing radio quality or corresponding TB size),
Concatenation of SDUs when the wireless bearers are the same in FFS,
In-sequence delivery of higher layer PDUs,
Duplicate detection,
Protocol error detection and restoration,
SDU discard,
reset,
Can be mentioned.

The ARQ function provided by the RLC layer will be discussed in more detail below.

[LTE uplink access method]
In the case of uplink transmission, power-efficient user terminal transmission is required to maximize the service area. As the evolved UTRA uplink transmission method, single carrier transmission combined with FDMA with dynamic bandwidth allocation has been selected. The main reason why single-carrier transmission is prioritized is that the peak-to-average power ratio (PAPR) is lower compared to multi-carrier signals (OFDMA), correspondingly improving the efficiency of the power amplifier and improving the service area. (The data rate is high for a given terminal peak power). At each time interval, the eNodeB ensures intra-cell orthogonality by allocating users with unique time / frequency resources to transmit user data. Orthogonal access on the uplink is expected to improve spectral efficiency by excluding in-cell interference. Interference caused by multipath propagation is handled by the base station (eNodeB) by inserting a cyclic prefix into the transmitted signal.

The basic physical resource used for data transmission consists of a frequency resource of size BWgrant in one time interval (eg, subframe) to which the coding information bits are mapped. Note that the subframe, also referred to as the transmission time interval (TTI), is the minimum time interval for user data transmission. However, subframe concatenation allows the user to allocate a frequency resource BWgrant over a longer period of time than one TTI.

[Layer 1 / Layer 2 control signaling]
L1 / L2 control signaling needs to be sent along with the data over the downlink to inform the scheduled users of their respective allocation status, transport format, and information related to other data (eg HARQ). is there. Control signaling needs to be multiplexed with downlink data in subframes (assuming user allocation can vary from subframe to subframe). Note that the user allocation may be performed on a TTI (transmission time interval) basis and the TTI length is a multiple of the subframe. The TTI length may be fixed in the service area for all users, may be different for different users, or may be dynamic for each user. In general, L1 / L2 control signaling may be transmitted on a TTI-by-TTI basis. The L1 / L2 control signaling is transmitted over the physical downlink control channel (PDCCH). Note that uplink data transmissions and assignments to UL grants are also transmitted on the PDCCH.

In the following, detailed L1 / L2 control signaling information transmitted for each uplink allocation of DL allocation will be described.

[Downlink data transmission]
Along with the downlink packet data transmission, L1 / L2 control signaling is transmitted on a separate physical channel (PDCCH). This L1 / L2 control signaling usually includes information about:

• Physical resource to which data is transmitted (eg, subcarrier or subcarrier block in the case of OFDM, code in the case of CDMA): According to this information, the UE (receiver) identifies the resource to which the data is transmitted. can do.

-Transport format used for transmission: This can be considered as the data transport block size (payload size, information bit size), MCS (modulation / coding method) level, spectral efficiency, coding rate, and the like. According to this information (usually in conjunction with resource allocation), the UE (receiver) identifies the information bit size, modulation scheme, and code rate and initiates the demodulation, derate matching, and decoding processes. can do. In some cases, the modulation scheme may be explicitly transmitted.

・ Hybrid ARQ (HARQ) information:
Process Number: Allows the UE to identify the hybrid ARQ process to which the data is mapped.
Sequence number or new data indicator: Allows the UE to identify whether the transmission is a new packet or a retransmission packet.
Redundant and / or signal point placement version: Informs the UE of the hybrid ARQ redundant version used (required for derate matching) and / or the modulated signal point placement version used (required for demodulation).

-UE identification information (UE ID): L1 / L2 control signaling informs the target UE. In a conventional embodiment, this information is used to prevent other UEs from reading this information by masking the CRC of the L1 / L2 control signaling.

[Uplink data transmission]
In order to enable uplink packet data transmission, the UE is informed of the transmission details by transmitting the L1 / L2 control signaling on the downlink (PDCCH). This L1 / L2 control signaling usually includes information about:

A physical resource to which the UE should send data (eg, a subcarrier or subcarrier block in the case of OFDM, a code in the case of CDMA).

-Transport format that the UE should use for transmission: This may be the data transport block size (payload size, information bit size), MCS (modulation / coding method) level, spectral efficiency, coding rate, etc. .. According to this information (usually in conjunction with resource allocation), the UE (transmitter) obtains the information bit size, modulation scheme, and code rate to initiate the modulation, rate matching, and coding process. Can be done. In some cases, the modulation scheme may be explicitly transmitted.

・ Hybrid ARQ information:
Process number: Informs the UE of the hybrid ARQ process for which data should be obtained.
Sequence number or new data indicator: Tells the UE to send a new packet or resend a packet.
Redundant and / or signal point placement version: Informs the UE of the hybrid ARQ redundant version to use (required for rate matching) and / or the modulated signal point placement version to use (required for modulation).
UE identification information (UE ID): Notifies the UE to which data should be transmitted. In a conventional embodiment, this information is used to prevent other UEs from reading this information by masking the CRC of the L1 / L2 control signaling.

There are several different characteristics of the exact method of transmitting the information described above. Further, the L1 / L2 control information may include other information, or a part of the information may be omitted. For example:

• For synchronous HARQ protocols, the HARQ process number may not be needed.

• If chase synthesis is used (always the same verbose and / or signal point placement version) or if the verbose and / or signal point placement version sequence is predefined, then the redundancy and / or signal point placement version is not needed there is a possibility.

-Power control information may be included separately in the control signaling.

-For example, MIMO-related control information such as precoding may be separately included in the control signaling.

-For multi-codeword MIMO transmission, the transport format and / or HARQ information of a plurality of codewords may be included.

In the case of uplink resource allocation (PUSCH) transmitted on the LTE PDCCH, the HARQ process number is not included in the L1 / L2 control information because the synchronous HARQ protocol is adopted for the LTE uplink. The HARQ process used for uplink transmission is given by timing. In addition, redundant version (RV) information is encoded along with the transport format information. That is, note that the RV information is embedded in the Transport Format (TF) field. Each MCS field in the TF has a size of, for example, 5 bits and corresponds to 32 entries. Three TF / MCS table entries are reserved for the designation of RV1, 2, or 3. Other MCS table entries are used to convey the MCS level (TBS), which implicitly specifies RV0. The size of the CRC field of PDCCH is 16 bits. More information on control information for uplink resource allocation on the PUSCH can be found in TS 36.212, section 5.3.3 and TS 36.213, section 8.6.

In the case of downlink allocation (PDSCH) transmitted over LTE PDCCH, the redundant version (RV) is transmitted separately in a 2-bit field. In addition, the modulation sequence information is encoded along with the transport format information. As in the case of the uplink, a 5-bit MCS field is transmitted on the PDCCH. Three of the entries are reserved to convey the explicit modulation sequence and no transport format (transport block) information is provided. Modulation sequence and transport block size information is transmitted for the other 29 entries. Details regarding control information for uplink resource allocation on the PUSCH can be found in TS 36.212, section 5.3.3 and TS 36.213, section 7.1.7, which are described herein. Invite to.

[E-UTRAN measurement-measurement gaps]
The E-UTRAN can report measurement information and configure the UE to support, for example, control of UE mobility. Each measurement configuration element is signaled by an RRCConceptionReconfiguration message. For example, the UE may allow the measurement to be performed because the measurement gap defines the amount of time that uplink or downlink transmissions are not scheduled. The measurement gap is common to all measurements using the gap. Inter-frequency measurements may require the setting of measurement gaps, depending on the capabilities of the UE (eg, whether it has dual receivers). The UE identifies an E-UTRA cell operating on a carrier frequency other than the serving cell. If the UE does not have more than one receiver, inter-frequency measurements, including cell identification, are performed in a periodic measurement gap. Two possible gap patterns, each with a length of 6 ms, can be set by the network. In the gap pattern # 0, a gap is generated every 40 ms, while in the gap pattern # 1, a gap is generated every 80 ms.

For example, the reference signal received power (RSRP) is measured by the UE for a cell-specific reference signal within the measurement bandwidth over the measurement period.

[ARQ / Hybrid ARQ (HARQ) method]
In LTE, there are two levels of retransmission that give reliability: HARQ in the MAC layer and external ARQ (outer ARQ) in the RLC layer. The RLC retransmission mechanism is responsible for providing error-free data delivery to higher layers. To achieve this, the (re) transmission protocol operates between the receiver and transmitter RLC entities, for example in response mode. Transmission errors due to noise, unpredictable channel variation, etc. can be handled by the RLC layer, but in most cases are handled by the MAC layer's HARQ retransmission protocol. Therefore, the use of the RLC layer retransmission mechanism may initially appear unnecessary. However, the facts are different, and in reality, the difference in feedback signaling is a sufficient trigger for both RLC-based and MAC-based retransmission mechanisms. For example, the RLC-ARQ mechanism addresses potential NACK vs. ACK errors that can occur with the MAC HARQ mechanism.

A common technique for error detection and correction of packet transmission systems on unreliable channels is referred to as hybrid automatic repeat request (HARQ). A hybrid ARP is a combination of forward error correction (FEC) and an ARQ. If an FEC-encoded packet is transmitted and the receiver cannot correctly decode the packet (errors are usually checked by a CRC (Cyclic Redundancy Check)), the receiver requests the packet to be retransmitted.

[RLC retransmission protocol]
If the RLC is set to request the retransmission of lost PDUs, it is believed that it is operating in response mode (AM: Acknowledged Mode). This is similar to the corresponding mechanism used in WCDMA / HSPA.

As a whole, the RLC has three operation modes: a transparent mode (TM), an unacknowledged mode (UM), and an acknowledged mode (AM). Each RLC entity is configured by the RRC to operate in one of these modes.

In transparent mode, no protocol overhead is added to the RLC SDU received from the upper layer. In special cases, transmission with limited split / reassembly capability can be achieved. In the wireless bearer setup procedure, it is necessary to decide whether or not to use split / reassembly. The transparent mode is used for services that are highly susceptible to delays, such as conversations.

In non-responsive mode, data delivery is not guaranteed because no retransmission protocol is used. The PDU structure contains a sequence number for integrity observation in the upper layer. Based on the RLC sequence number, the receiving UM RLC entity can perform a sort of receiving RLC PDU. Splitting and concatenating are provided by header fields added to the data. The RLC entity in non-responsive mode is unidirectional because no association is defined between the uplink and the downlink. If incorrect data is received, the corresponding PDU will be discarded or marked according to the settings. In the transmitter, RLC SDUs that are not transmitted within a certain time specified by the timer are discarded and excluded from the transmission buffer. The RLC SDU received from the upper layer is divided / connected to the RLC PDU on the transmitting side. On the receiving side, reassembly is performed in response to this. Non-responsive mode is used for services where error-free delivery is less important than short delivery times, such as cell broadcast services such as MBMS and voice over IP (VoIP) for certain RRC signaling procedures. ..

In response mode, the RLC layer supports error correction with the Automatic Repeat Request (ARQ) protocol and is typically used for IP-based services such as file transfers that are of primary concern for error-free data delivery. .. RLC retransmissions are based on, for example, an RLC status report or ACK / NACK received from a peer RLC receiving entity. The response mode is designed for reliable packet data transmission by retransmission in the presence of high air interface bit error rates. In the case of PDU error or loss, the transmitter will retransmit in response to the receipt of the RLC status report from the receiver.

ARQ is used as a retransmission method for retransmission of erroneous or lost PDUs. For example, by monitoring the input sequence number, the receiving RLC entity can identify the lost PDU. The receiving RLC can then generate an RLC status report and feed it back to the transmitting RLC entity to request the retransmission of the lost or undecrypted PDU. In addition, the RLC status report can be polled by the transmitter. That is, the RLC transmitter uses the polling function to acquire a status report from the RLC receiver to inform the RLC transmitter of the receive buffer status. The status report provides acknowledgment (ACK) or negative response information (NACK) on the RLC data PDU or a portion thereof until the last RLC data PDU for which HARQ sorting is completed. The RLC receiver triggers a status report if the PDU with polling fields is set to "1" or if it is detected that the RLC data PDU has been lost. Section 5.2.3 of TS 36.322 (current version 13.0.0) specifies specific triggers that trigger polling of RLC status reports in RLC transmitters, which are described herein. Invite to. In the transmitter, transmission is allowed only to the PDU in the transmission window, and the transmission window is updated only by the RLC status report. Therefore, if the RLC status report is delayed, the transmission window cannot be advanced and transmission may be stagnant.

The receiver sends an RLC status report to the transmitter when triggered.

As already mentioned above, in addition to data PDU delivery, control PDUs can be transmitted between peer entities.

[MAC HARQ protocol]
The MAC layer includes a HARQ entity responsible for transmission and reception HARQ operations. Transmission HARQ operations include transmission and retransmission of transport blocks and reception and processing of ACK / NACK signaling. Received HARQ operations include receiving transport blocks, synthesizing received data, and generating ACK / NACK signaling. Supports multi-process "stop and wait" (SAW) HARQ operation by using up to eight HARQ parallel processes to allow continuous transmission while the previous transport block is being decrypted. Each HARQ process is responsible for a separate SAW operation and manages a separate buffer.

The feedback provided by the HARQ protocol is a response (ACK: Acknowledgement) or a negative response (NACK: Negative Acknowledgement). The ACK and NACK are generated depending on whether the transmission can be received correctly (for example, whether the decryption is successful). In addition, in HARQ operation, in retransmission, different coding from the original transport block so that the UE employs Incremental Redundancy (IR) synthesis to obtain a different coding gain from the synthesis gain. The version can be transmitted by eNB.

If an FEC-encoded packet is transmitted and the receiver cannot correctly decode the packet (errors are usually checked by a CRC (Cyclic Redundancy Check)), the receiver requests the packet to be retransmitted. Generally (and throughout the specification), the transmission of additional information is referred to as a "retransmission (of a packet)", which may mean the transmission of the same encoded information, but not necessarily. Doesn't mean. It can also mean the transmission of arbitrary information belonging to a packet (eg, additional redundancy information), eg, by using different redundant versions.

In general, the HARQ scheme can be classified as synchronous or asynchronous, and the retransmission in each case is adaptive or non-adaptive. Synchronous HARQ means that the retransmission of the transport block of each HARQ process occurs at a predetermined (periodic) time with respect to the initial transmission. Therefore, since it can be inferred from the transmission timing, no explicit signaling is required to indicate the retransmission schedule or, for example, the HARQ process number to the receiver.

On the other hand, according to asynchronous HARQ, retransmission can occur at any time with respect to the initial transmission. This gives the flexibility to schedule retransmissions based on air interface conditions. However, in this case, another explicit signaling is required, for example, to show the HARQ process to the receiver to allow correct synthesis and protocol operation. In the 3GPP LTE system, HARQ operation involving eight processes is used.

In LTE, asynchronous adaptive HARQ is used for the downlink and synchronous HARQ is used for the uplink. In the uplink, the retransmission may be adaptive or non-adaptive, depending on, for example, the uplink grant being given new signaling of the transmit attribute.

In the uplink HARQ protocol operation (ie, the response of the uplink data transmission), there are two different options regarding how to schedule retransmissions. Retransmission is either "scheduled" by NACK (also referred to as synchronous non-adaptive retransmission) or explicit scheduling by the network by transmission of PDCCH (also referred to as synchronous adaptive retransmission).

For synchronous non-adaptive retransmissions, this retransmission will use the same parameters as the previous uplink transmission. That is, this retransmission will be carried on the same physical channel resource, each using the same modulation / transport format. However, the redundant version changes, that is, circulates in a predetermined sequence of redundant versions of 0, 2, 3, and 1.

Since synchronous adaptive retransmissions are explicitly scheduled by the PDCCH, the eNodeB can change certain parameters of the retransmissions. To avoid disruption in the uplink, it is possible to schedule retransmissions, for example, on different frequency resources, change the modulation scheme by eNodeB, or indicate to the user equipment the redundant version to use for retransmissions. It is also possible. Note that in the case of UL HARQ FDD operation, HARQ feedback (ACK / NACK) and PDCCH signaling occur at the same timing. Therefore, the user equipment determines whether a synchronous non-adaptive retransmission is triggered (ie, only NACK is being received) or whether the eNodeB is requesting a synchronous adaptive retransmission (ie, is PDCCH also being transmitted). You only have to check it once.

PHICH carries HARQ feedback indicating whether the eNodeB has correctly received the transmission on the PUSCH. The HARQ indicator is set to 0 in the case of an acknowledgment (ACK) and 1 in the case of a negative response (NACK). The PHICH that carries the ACK / NACK message for uplink data transmission may be transmitted to the same user terminal at the same time as the physical downlink control channel PDCCH. By such simultaneous transmission, the user terminal can perform new transmission (a new UL grant for switching NDI) or retransmission (referred to as adaptive retransmission) (NDI) regardless of the instruction to the terminal by PDCCH, that is, the content of PHICH. It is possible to determine an instruction to execute a new UL grant that does not switch. If the PDCCH of the terminal is not detected, the contents of PHICH determine the UL HARQ behavior of the terminal, which can be summarized as follows.

NACK: The terminal performs a non-adaptive retransmission, i.e., a retransmission on the same uplink resource that was previously used in the same HARQ process.

ACK: The terminal does not perform any uplink retransmissions and keeps the data in the HARQ buffer during the HARQ process. Separate transmissions for the HARQ process require explicit scheduling by subsequent grants by PDCCH. Until the reception of such a grant, the terminal is in the "suspended state".

This is shown in Table 1 below.

The schedule timing of the uplink HARQ protocol in LTE is illustrated in FIG. The eNB transmits the first uplink grant 301 to the UE on the PDCCH, and in response, the UE transmits the first data 302 to the eNB on the PUSCH. The timing between the PDCCH uplink grant and the PUSCH transmission is currently fixed at 4 ms. After receiving the first data transmission 302 from the UE, the eNB transmits the feedback information (ACK / NACK) of the received transmission and, for example, the UL grant 303 to the UE (or if the UL transmission is successful). The eNB may be triggering a new uplink transmission by transmitting a suitable second uplink ground). The time between the PUSCH transmission and the corresponding PHICH carrying the feedback information is also currently fixed at 4 ms. As a result, the Round Trip Time (RTT) indicating the next (re) transmission opportunity in the uplink HARQ protocol is 8 ms. After this 8 ms, the UE may transmit the retransmit 304 of the previous data instructed by the eNB. For this separate operation, the retransmission 304 of the previously transmitted data packet was unsuccessful again, as the eNodeB instructed the UE to perform another retransmission (eg, sending NACK305 as feedback). Suppose that. In response to this, the UE will separately execute the retransmission 306.

The upper part of FIG. 3 shows the subframe numbering as well as an exemplary association with the HARQ process subframe. As is clear from this, each of the eight available HARQ processes is cyclically associated with each subframe. In the exemplary scenario of FIG. 3, it is assumed that the initial transmission 302 and its corresponding retransmissions 304 and 306 are processed by the same HARQ process number 5.

The measurement gap in which the measurement is performed on the UE has a higher priority than the HARQ retransmission. Therefore, whenever the HARQ retransmission collides with the measurement gap, the HARQ retransmission does not occur. On the other hand, whenever the HARQ feedback transmission on PHICH collides with the measurement gap, the UE assumes that the ACK is the expected content of the HARQ feedback.

The downlink control information has a plurality of fields that assist the HARQ operation.

• New Data Indicator (NDI): Switched each time a transport block transmission is scheduled (ie, also referred to as the initial transmission) (“Switch” to the previously transmitted value of this HARQ process. On the other hand, it means that the NDI bit given in the relevant HARQ information has been changed / switched).
Redundant Version (RV): Indicates the RV selected for transmission or retransmission credit.
・ MCS: Modulation / coding method

The HARQ operation is complex, not fully described / not fully described herein, nor is it necessary to fully understand the present invention. The relevant part of the HARQ operation is described, for example, in Section 5.4.2 “HARQ operation” of 3GPP TS 36.321 (current version 13.0.0), which is incorporated herein by reference. Some of them are quoted below.

"5.4.2 HARQ operation 5.4.2.1 HARQ entity In a MAC entity, there is one HARQ entity for each serving cell with an uplink, and HARQ feedback regarding successful or unsuccessful reception of previous transmissions. While waiting, maintain many parallel HARQ processes that allow transmission to occur continuously.
The number of parallel HARQ processes per HARQ entity is specified in Section 8 [2].
When the physical layer is configured for uplink space multiplexing [2], a given TTI is associated with two HARQ processes. Otherwise, a given TTI is associated with one HARQ process.
In a given TTI, if the TTI shows an uplink grant, the HARQ entity identifies the HARQ process to make the transmission. It also routes received HARQ feedback (ACK / NACK information), MCS, and resources relayed by the physical layer to the appropriate HARQ process.
If a TTI bundle is set, the parameter TTI_BUNDLE_SIZE gives the number of TTIs in the TTI bundle. The TTI bundle operation relies on a HARQ entity that calls the same HARQ process for each transmission that is part of the same bundle. Within the bundle, HARQ retransmissions are non-adaptive and are triggered according to TTI_BUNDLE_SIZE without waiting for feedback from previous transmissions. HARQ feedback for a bundle is received only at that TTI, regardless of whether transmission occurs at the last TTI of the bundle (ie, the TTI corresponding to TTI_BUNDLE_SIZE) (eg, in the event of a measurement gap). Retransmission of the TTI bundle is also a TTI bundle. TTI bundles are not supported when one or more SCells with uplinks are configured for the MAC entity.
The TTI bundle is not supported for RN communication where E-UTRAN is combined with the RN subframe setting.
The TTI bundle does not apply to the transmission of Msg3 during random access (see Section 5.1.5).
For each TTI, the HARQ entity is
Identify the HARQ processes associated with this TTI, and for each identified HARQ process,
If an uplink grant is indicated for this process and this TTI
If the receive grant is not addressed to the provisional C-RNTI on the PDCCH and the NDI given in the relevant HARQ information is switched to the previously transmitted value of this HARQ process. Or if an uplink grant has been received on the PDCCH for C-RNTI and the HARQ buffer of the identification process is empty, or if an uplink grant has been received in a random access response.
If there is a MAC PDU in the Msg3 buffer and an uplink grant is received in the random access response
Acquires the MAC PDU to be transmitted from the Msg3 buffer.
In cases other than the above
Get the MAC PDU sent from the "multiplexed / assembled" entity.
Deliver MAC PDUs, uplink grants, and HARQ information to the identifying HARQ process.
Directs the identification HARQ process to trigger a new transmission.
In cases other than the above
Deliver uplink grants and HARQ information (redundant version) to the identifying HARQ process.
Directs the identification HARQ process to generate adaptive retransmissions.
In cases other than the above, if the HARQ buffer of this HARQ process is not empty,
Directs the identification HARQ process to generate non-adaptive retransmissions.
When determining whether the NDI has been switched relative to the value of the previous transmission, the MAC entity shall ignore the NDI received at all uplink grants on the PDCCH with respect to its provisional C-RNTI. "

[NB-IoT / eMTC Uplink HARQ Protocol]
For NB-IoT and eMTC (Rel.13), an asynchronous UL HARQ protocol has been introduced (also discussed for the ongoing Rel.14 work item on uplinks on unlicensed carriers). Unlike the synchronous uplink HARQ protocol used for traditional LTE, retransmissions to NB-IoT or eMTC UEs are adaptive and asynchronous. More specifically, retransmissions do not have to occur at a fixed timing for previous HARQ transmissions in the same process, giving the flexibility to explicitly schedule retransmissions. Moreover, there will be no explicit HARQ feedback channel (PHICH). That is, retransmission / initial transmission is indicated by PDCCH (NDI is distinguished by initial transmission and retransmission). In essence, the uplink HARQ protocol behavior for NB-IoT or eMTC UEs will closely resemble the asynchronous HARQ protocol used for downlinks after Rel-8.

Note that for NB-IoT, there is only one UL HARQ process.

For details of the asynchronous uplink HARQ protocol introduced in the NB-IoT / eMTC UE, refer to Section 5.4.2 of 3GPP TS 36.321 (V13.1.0) (2016-03). , Which is incorporated herein by reference.

[Short Latency Study Item]
Packet data latency is one of the performance metrics that vendors, businesses, and end users (by speed test applications) measure on a regular basis. Latency measurements are taken at all stages of the radio access network system's useful life when identifying new software releases or system components, deploying the system, and commercializing the system.

Greater latency than previous generations of 3GPP RAT was one of the performance metrics that guided LTE design. LTE is now also recognized by end users as a system that provides faster Internet access and lower data latency than previous generations of mobile wireless technology.

In the 3GPP community, great efforts have been made to improve data rates from the first release of LTE (Rel.8) to the latest release (Rel.12). Features such as Carrier Aggregation (CA), 8x8 MIMO, and 256QAM have increased the technical potential of L1 data rates from 300 Mbps to 4 Gbps. Rel. In 13, 3GPP aims to introduce even higher bit rates by introducing up to 32 component carriers in CA.

However, almost nothing has been done about the separate improvement specifically targeting system delays. Packet data latency is not only important to the perceived responsiveness of the system, it is also a parameter that indirectly affects throughput. HTTP / TCP is a predominant set of application and transport layer protocols used on the Internet today. According to the HTTP Archive (http://httptparchive.org/trends.php), the typical size of HTTP-based transactions on the Internet ranges from tens of Kbytes to 1 Mbytes. Within this size range, the TCP slow start period is the majority of the total transmission period of the packet stream. At TCP slow start, performance is constrained by latency. Therefore, for this type of TCP-based data transaction, it is fairly easy to show an improvement in latency to improve average throughput. Further, in order to actually realize a high bit rate (the range of Gbps in Rel.13 CA), it is necessary to specify the size of the UE buffer accordingly. The longer the RTT, the larger the buffer required. The only way to reduce buffering requirements on the UE and eNB side is to reduce latency.

Reducing latency can also have a positive effect on the efficiency of radio resources. Low packet data latency increases the number of possible transmission attempts within a certain delay range, which also allows the use of higher BLER targets for data transmission, which removes the limitation of radio resources while inadequate radio conditions. It keeps the same level of robustness for users. Increasing the number of possible transmissions within a certain delay range also allows for more robust transmissions of real-time data streams (eg, VoLTE) if the same BLER target is maintained. This will increase the capacity of the VoLTE voice system.

In many existing applications, there are many others that are positively impacted by low latency in terms of improving the perceived quality of experience. Examples include games, real-time applications such as VoLTE / OTT VoIP, and videophone / conferencing.

In the future, there will be many new applications where latency is becoming more and more important. Examples include remote control / driving of vehicles, such as augmented reality applications in smart glasses, or certain machine communications that require low latency and critical communications.

Various pre-scheduling methods can be used to reduce latency to some extent, but Rel. Like the Low Scheduling Request (SR) Interval introduced in 9, it does not necessarily address all aspects of efficiency.

It should also be noted that if the latency of user plane data is reduced, the transmission of control signaling will be faster, which may indirectly shorten the call setup / bearer setup time.

Therefore, in order to ensure the evolution and competitiveness of LTE, it is necessary to study and improve the packet data latency.

The purpose of this study is to consider strengthening the E-UTRAN wireless system.
· Significantly reduces packet data latency on the LTE-Uu air interface of a valid UE and
-Significantly reduces the packet data transport round-trip latency of UEs that have been disabled for a long time (in the connected state).
That is.

Scope of consideration includes resource efficiency such as air interface capacity, battery life, control channel resources, specification impact, and technical feasibility. Both FDD and TDD dual modes are conceivable.

As a first aspect, potential benefits such as reduced response times and improved TCP throughput by improving latency in normal applications and use cases are identified and documented. In conclusion, this aspect of the study indicates that reduced latency is desirable.

As a second aspect, the following areas shall be considered and documented.

High-speed uplink access solution For UEs that are valid and UEs that have been disabled for a long time but have RRC connections maintained, the current standards for both keeping and not keeping the current TTI length and processing time. The focus shall be on reducing the user plane latency of scheduled UL transmissions and obtaining a resource-efficient solution with enhanced protocol and signaling by comparison with the pre-scheduling solution that enables it.
-Reduced TTI and processing time Evaluate the specification impact, study feasibility, and performance of the TTI length between 0.5 ms and the OFDM symbol, taking into account the impact on reference signals and physical layer control signaling. To do.
Backward compatibility shall be maintained (this allows normal operation of Rel.13 and earlier UEs on the same carrier).

[Processing chain function for uplink]
For the processing chain shown in FIG. 4, reference is made to Section 5.2.2 of 3GPP TS 36.212 (V13.1.0) (2016-03), which is incorporated herein by reference.

FIG. 4 is a block diagram including a coding chain function within the physical layer of a single codeword / transport block. The input consists of transport blocks inherited by the MAC layer. Due to the retransmission of the transport block, the redundant version (RV) is an input parameter within the "rate matching block". As a result, if different RVs are used for retransmission, at least the blocks "rate matching", "code block concatenation", "data / control multiplexing", and "channel interleaver" need to be processed.

The output of the block "channel interleaver" serves as a "codeword" input to the physical channel processing step shown in FIG. 5, for which 3GPP TS 36.211 (V13.1.0) (2016-03). ), Paragraph 5.3, which is incorporated herein by reference.

FIG. 5 is a block diagram including a physical channel processing function in the physical layer. The input consists of codewords obtained as a result of the coding chain shown in [36.212] Figure 5.2.2-1. For normal (non-MTC or NB-IoT) processing, the "scramble" block has a transmit subframe index within the radio frame in its input parameters. Therefore, even if the codeword input is the same, the output of the "scrambled" block will be different if the subframe index is different. Due to the retransmission of the transport block, the redundant version (RV) is an input parameter within the "rate matching block". As a result, if different RVs are used for retransmission, at least the blocks "rate matching", "code block concatenation", "data / control multiplexing", and "channel interleaver" need to be processed.

Non-limiting and exemplary embodiments provide improved transmission protocol behavior for the transmission of uplink data packets in user equipment.

The independent claims provide non-limiting and exemplary embodiments. A favorable embodiment corresponds to the dependent claim.

According to a plurality of aspects described herein, transmission protocol behavior shall be improved.

According to a general aspect, a user device that operates a transmission protocol for uplink data packet transmission in a communication system and includes a receiver that receives a high-speed retransmission indicator is described. Therefore, the fast retransmission indicator indicates whether the base station requires the retransmission of previously transmitted data packets. The user equipment comprises a transmitter that retransmits the data packet with the same redundant version already used for the previous transmission of the data packet.

According to another general aspect, a base station that operates a transmission protocol for uplink data packet transmission in a communication system and includes a transmitter that transmits a high-speed retransmission indicator is described. Therefore, the high-speed retransmission indicator indicates to the user equipment whether or not the base station requests the retransmission of the previously transmitted data packet. The base station comprises a receiver that receives from the user equipment a redundant version of the retransmission data packet that was already used by the user equipment for the previous transmission of the data packet.

Corresponding to the above, in another general aspect, the technique disclosed herein features a method of operating a transmission protocol for uplink data packet transmission in a communication system in a user device. This method is a step of receiving a fast retransmission indicator called FRI, which receives a fast retransmission indicator indicating whether the base station is requesting the retransmission of previously transmitted data packets. Includes steps to do. The method further comprises retransmitting the data packet with the same redundant version already used for the previous transmission of the data packet.

Corresponding to the above, in another general aspect, the technique disclosed herein features a method of operating a transmission protocol for uplink data packet transmission in a communication system at a base station. This method is a step of transmitting a high speed retransmission indicator called FRI, in which the FRI transmits a high speed retransmission indicator indicating to the user whether or not a previously transmitted data packet is required to be retransmitted. Includes steps to do. The method further comprises receiving from the user equipment a redundant version of the retransmission data packet that was already used by the user equipment for the previous transmission of the data packet.

Other benefits and benefits of the disclosed embodiments will become apparent from the specification and drawings. These benefits and / or benefits may be provided individually by the various embodiments and features of the specification and drawings of the disclosure, but not all, one or more of them. It may be obtained.

These general and specific embodiments may be implemented using systems, methods, and computer programs, as well as any combination of systems, methods, and computer programs.

Hereinafter, exemplary embodiments will be described in more detail with reference to the accompanying drawings.

It is a figure which showed the exemplary architecture of the 3GPP LTE system. It is a figure which showed the exemplary downlink resource grid of the downlink slot of the subframe specified for 3GPP LTE (Rel.8 / 9). It is a figure which illustrated the transmission protocol operation between a UE and an eNodeB in the case of an uplink transmission and its retransmission. FIG. 6 is a schematic block diagram including a coding chain function within the physical layer of a single codeword / transport block. It is a schematic block diagram including a physical channel processing function in a physical layer. It is a transmission request and the corresponding transmission timing chart which concerns on this embodiment. FIG. 5 is a timing chart of a transmission request and a corresponding transmission in the case where simultaneous requested retransmissions collide according to the present embodiment.

As can be seen from FIG. 3 and its description in the "Background" section, there is currently a 4 ms delay between PDCCH / PHICH and the corresponding PUSCH uplink transmission. This delay is primarily due to the PDCCH / PHICH detection as well as the processing required on the UE side, including the coding chain and physical channel processing steps outlined above. This 4 ms latency can also be reduced by shortening the TTI, as discussed within the "short latency" considerations above, but the major time savings are reduced transport block size and faster processing. Due to potential improvements in hardware / software design that enable. Nonetheless, such savings are still outlined above, even in the case of retransmissions, especially when different RVs are used for retransmissions compared to previous transmissions of the same transport block (data packet). As you can see, it is constrained by the need to handle all functional blocks in the transmit chain.

Another delay, currently as long as 4 ms, has a gap between the PUSCH transmission and the next potential trigger by PDCCH / PHICH for the same HARQ process. This gap is the need for the eNB to process the PUSCH and attempt to decrypt it, and if the decryption attempt fails, redetermine proper scheduling and link adaptation procedures to send the uplinks of other users. Also need to be taken into account because it is necessary to determine the appropriate set of physical layer transmit parameters for retransmission credit, including MCS, number and position of RBs, RVs, transmit power. Finally, once these parameters are determined, they need to be carried to the UE by (E) DCI on the PDCCH and / or HI on PHICH (in the case of non-adaptive retransmission). ..

Although it is possible to see PHICH as a compact way to trigger non-adaptive retransmissions, especially due to scrambling that depends on different RV versions and subframes, the UE still takes quite a few steps before it can be transmitted. Need to do.

An object of the present invention is to reduce the delay between transmission on the PUSCH from the UE and the corresponding retransmission instruction by the eNodeB. Another object is to reduce the delay between the retransmit instruction by the eNodeB and the corresponding retransmission on the PUSCH from the UE.

According to the inventors, the following exemplary embodiments can be considered to alleviate one or more of the problems described above.

Specific embodiments of the plurality of variants of this embodiment will be realized in the broad specifications set forth in the 3GPP standard, some of which are also described in the "Background" section, but certain key features. Will be added in the following description of the described embodiments. Although it is convenient that this embodiment can be used in a mobile communication system such as the 3GPP LTE-A (Rel.10 / 11/12/13) communication system described in the above "Background Technology" section, this embodiment is convenient. Note that it is not limited to use in certain exemplary communication networks.

It should be understood that the following description does not limit the scope of the present disclosure and is merely an example of an embodiment for a deeper understanding of the present disclosure. One of ordinary skill in the art will recognize that the general principles of the disclosure described in the claims can be applied to a variety of scenarios in a manner not expressly described herein. Although some assumptions have been made for convenience of explanation, these do not limit the scope of the following embodiments.

Hereinafter, an embodiment for solving the above-mentioned problems will be described in detail. Different embodiments and modifications of the present embodiment will be described in the same manner.

The present embodiment provides a user device (UE) that operates a transmission protocol for transmitting uplink data packets in a communication system. According to this transmission protocol, if the attempt to decode the PUSCH fails in the eNodeB, a fast retransmission indicator (FRI) is used in the UE to trigger a fast retransmission in a short time. When this FRI is adopted, the retransmission request can be transmitted by eNodeB faster than when DCI / HI is used.

Because the UE retransmits data packets faster than it responds to DCI, the UE only uses the same radio resources as a trigger for non-adaptive retransmission by HI, according to a variant of this embodiment. Alternatively, the same other parameters that were applicable to the latest transmitted data packet triggered by DCI or HI may be used to retransmit the data packet.

Similarly, the present embodiment is a base station that operates the transmission protocol of the uplink data packet transmission, and whether or not the transmission of the FRI to the UE requires the retransmission of the previously transmitted data packet. Provide a base station indicating. In response to such a request, the base station receives from the UE the same redundant version of the retransmission data packet that was already used for the previous transmission of the data packet.

As a general consideration, for example, due to urgent quality-of-service requirements, when eNodeB attempts to trigger fast retransmissions of data packets, non-optimal use of radio channel capacity is used as much as possible. At the expense, it is more important to retransmit as fast as possible. As a major aspect of achieving such high-speed retransmission of data packets, eNodeB needs to perform a complete link adaptation evaluation because all parameters have already been determined for the previous transmission of data packets. There is no.

As explained in the "Background" section, even if HI is used for retransmission, the redundant version will change for the retransmission data block. In this case, the redundant versions circulate in a predetermined sequence of redundant versions, for example 0, 2, 3, 1. As shown in FIG. 4, the redundant version specifically selected for retransmission is the input value of the "rate matching" block. Therefore, at least the blocks "rate matching", "code block concatenation", "data control multiplexing", and "channel interleaver" are processed again for each retransmission data block using a different redundant version (RV). There is a need. Further, the output of the "channel interleaver" block is input to the entire physical channel processing shown in FIG.

In one embodiment of this embodiment, the UE uses the same redundant version of the data packet that was already used for the previous transmission of the data packet in order to achieve a significant reduction in the time required to transmit the retransmission of the data packet. Used for retransmission of. All associated changes in the redundant version of a data packet because the UE uses the same subset of transmit parameters as the previous DCI trigger transmission, that is, the same redundant version as the previously transmitted data packet, to retransmit the data packet. The processing step can be omitted.

That is, a new "rate matching" and subsequent block (shown in FIG. 5) until the start of scrambling (shown in FIG. 5), even if only using the same RV as the previous DCI (or HI) triggered transmission of the data packet. It is not necessary to process (shown in FIG. 4). In other words, if the UE is buffering the most recently transmitted codewords, this is sufficient for fast retransmissions and, as shown in FIG. 5, these buffered codewords are physically channeled. Supply to.

FIG. 6 shows a transmission request and a corresponding transmission timing chart. As can be seen from this figure, the period between the transmission of DCI by the eNodeB and the corresponding transmission of the data packet by the UE is shown as the period t0, which period t0 is referred to as the "third timing". There may be. In the case of the uplink HARQ protocol adopted from LTE Release 8, the period t0 corresponds to a period of 4 ms as shown in FIG. 3, indicating the conventional case of triggering uplink data transmission by DCI. .. As can be seen from FIG. 6, in contrast to FIG. 3, the period t1 (also shown in FIG. 6) between the transmission of the data packet by the UE (PUSCH) and the transmission of the FRI by the eNodeB is t0 or less. Good. On the other hand, in a preferred modification of this embodiment, t1 is shorter than the period t0. Further development in the future may result in a period t0 of less than 4 ms, but this does not limit the scope of the invention, and the description of this embodiment states that the period t0 is 4 ms unless otherwise specified. Suppose.

Therefore, as another modification of the present embodiment, the period t1 that can be called "first timing" is a fixed period or a period that can be quasi-statically set by the base station and is less than 4 ms. Is preferable.

Note that FRI can generally exhibit at least two states. According to "state 1", the FRI is a "positive FRI" and triggers fast retransmissions, while in this case it may also be considered a negative response of the received data packet. According to "state 2", the FRI is a "negative FRI" and does not trigger fast retransmissions. In this case, it may be regarded as an acknowledgment of the received data packet. Therefore, a functionally equivalent interpretation of the state is that "acknowledgement FRI" is equivalent to FRI carrying "negative response (NACK)" and "negative FRI" is equivalent to FRI carrying "response (ACK)". Equivalent. For simplicity that does not limit the scope of this embodiment, only the terminology "affirmative FRI" and "negative FRI" will be used in the following description.

Further derived from FIG. 6, the period t2 defined as the time between the affirmative FRI transmitted by the eNodeB and the corresponding PUSCH transmission transmitted by the UE is the DCI (or HI) and the corresponding PUSCH. It must be shorter than the period t0, which is the period between transmissions. The reason why the period t2 is shorter than the period t0 is that the calculation time in the UE is saved by using the same subset of transmission parameters as the previous DCI / HI trigger transmission described above for the retransmission of the data packet. This is the result. FIG. 6 shows the use of the same redundant version. For example, by using redundant version RV # 0, both DCI-initiated PUSCH transmission and FRI-initiated PUSCH transmission are performed. In other words, RV # 0 is determined by DCI start PUSCH transmission and reused by FRI start PUSCH transmission.

Therefore, as another modification of this embodiment, the period t2, which can also be called "second timing", is included in the fixed period, the period that can be quasi-statically set by the base station, or the transmission / reception FRI. It is a variable based on each information. Preferably, the period t2 may be less than 4 ms.

According to another embodiment of the present embodiment, the affirmative FRI indicates that the retransmission is performed with the same additional transmission parameters as those used for the previous transmission of the data packet, but these additional identical The transmission parameter of is then used by the UE to retransmit the data packet and to receive the retransmitted data packet at the base station.

According to another embodiment of the present embodiment, the additional identical transmission parameter used to retransmit the data packet is at least the scramble code of the previously transmitted data packet. The advantage of having the same transmission parameters such as the same scramble code separately is that in addition to skipping from the above-mentioned block "rate matching" to "channel interleaver" as shown in FIG. 4, data packet retransmission is possible. There is no need to process the "scrambled" block shown in FIG.

In another variant of this embodiment, additional identical transmission parameters are re-used from the previous DCI start PUSCH transmission until when the precoding information becomes available, i.e. after the block "precoding" of FIG. It may be used. For example, from the previous DCI start PUSCH transmission, the same transmission method as the previous transmission may be used for the retransmission by reusing the modulation method and layer mapping with additional same transmission parameters. .. That is, the same number of transmission layers and the same antenna port may be used. Using the same precoding vector as in the previous transmission is most reasonable if the FRI does not indicate the use of a different precoder.

However, when the same transmission parameter is reused separately beyond the block “precoding” shown in FIG. 5 from the previous DCI start PUSCH transmission, only a part of the resource is used for the retransmission. For example, a "resource element mapper" block will map data to only some of the resources used for previous transmissions (eg, 50% of the resource block, some of the resource blocks). Similarly, in the case of high-speed retransmission, only a part of the output of the "resource element mapper" block is used as an input to the "SC-FDMA signal generation" block. Therefore, the UE buffers the output of the "resource element mapper" block of the previous transmission, and when triggering a partial retransmission, reads only the corresponding part from the buffer and uses it as an input to SC-FDMA signal generation. It is sufficient to apply these. The portion used for high-speed retransmission is preferably a multiple of a non-negative integer in reference time or frequency resource units, such as the "resource block" or "resource block group" defined in TS 36.213. This has the advantage that unused resources can be optimally allocated to other UEs without wasting resources due to some resource blocks or resource block groups. Further, the portion is assumed to be the bandwidth of the PUSCH with respect to resource blocks ^{M PUSCH} _RB, ^where, along with a _{^{M PUSCH RB = 2 α2 · 3}} α3 · 5 α5, α 2, α 3, α 5 Is a set of non-negative integers. Therefore, if the designated portion of bandwidth M ^PUSCH _RB as a case or result in a non-integer number of resource blocks or resource block groups does not satisfy the condition ^{2 α2 · 3 α3 · 5 α5} , UE is preferably designated and performs rounding up to the large minimum integer value ^{M PUSCH} _RB than the specified portion satisfies more than partial smallest integer number of resource blocks or resource block groups or _{^{M PUSCH RB = 2 α2 · 3}} α3 · 5 α5 , respectively.

In another modification of the present embodiment, the same "circular shift parameter" as the generation of the reference signal for retransmission credit of the data packet may be used as the same additional transmission parameter. In this regard, refer to Section 5.5.2 of 3GPP Technical Standard 36.211. By using the same "circular shift parameter" for the generated reference signal, the total processing time for retransmissions is further reduced. In another variant, the FRI transmitted by the eNodeB may further contain information about "circular shift parameters", which will be used by the UE to generate a reference signal for retransmission credit of the data packet.

The latest transmission of data blocks may not only consist of UL-SCH data, but may also include uplink control information (UCI) such as ACK / NACK, CSI. As can be seen from FIG. 4, such information is added to the data in the block "Data Control Multiplexing". In general, such information is preferably added to FRI-triggered retransmissions as well as the latest transmission of data blocks. However, it is not always rational to transmit the same ACK / NACK or CSI information. This is because the content can expire due to the delay between the previous transmission and the trigger retransmission. Thus, in another embodiment, the retransmission does not include the UCI, but reserves these resources as if the information were present. As a result, the order of the data block bits can be invariant, eliminating the need for a separate bit reordering procedure for retransmission.

Similarly, a part of the resources of the uplink subframe, preferably the end of the subframe, may include a Sounding Reference Symbol (SRS). In such cases, the fast retransmission may include SRS, as in previous transmissions. That is, resources are reserved (for example, mute). As a result, the mapping of PUSCHs to resource elements can remain unchanged, eliminating the need for a separate procedure for rearranging REs for retransmission.

With reference to FIGS. 6 and 7, if the data packet is not successfully received, the data packet is requested to be retransmitted from the UE using either FRI, DCI, or HI, and FRI, DCI, or Note that the eNodeB may flexibly determine which of the HIs to send to the UE. Similarly, the UE flexibly performs the corresponding transmission / retransmission of a data packet based on the received FRI, DCI, or HI, as described above, in response to any reception of the FRI, DCI, or HI. You may do so.

According to another embodiment of the present embodiment, the FRI indicates that a portion of the previously transmitted data packet will be retransmitted and, optionally, a portion of the previously transmitted data packet. 50% or 25% of. In such cases, the UE retransmits the indicated portion of the previously transmitted data packet. The UE may also adapt the transmit power to the retransmission so that the total transmit power of the retransmission of the above portion of the previously transmitted data packet is equal to the total transmit power of the previously transmitted data packet. Often, using 50% of the data packet, optionally, doubles the transmit power of the above portion of the previously transmitted data packet.

If only part of the frequency resources of the previous transmission is used for retransmission, then the total power transmitted by the UE for partial retransmission is also part. However, in order to improve the quality of the partially retransmitted data, their power can be increased to each other up to the proportion of frequency resources. For example, if only 50% of the frequency resources are used for partial retransmissions, each RE for partial retransmissions can be doubled, with full and full retransmissions for partial retransmissions. The total transmission power with and is equal. Such partial retransmissions do not require successful decoding of the transport block by full retransmissions, or eNodeB uses only part of the frequency resources for retransmissions and another for the rest. This is especially attractive if you want to allow the UE to schedule.

The amount of frequency resources used for partial retransmission can be determined as follows.
1. 1. Quasi-static setting: Whenever a positive FRI triggers a fast retransmission, the UE examines the setting and applies accordingly.
2. Designation within FRI: The FRI can carry indicators that determine the amount of partial resources. For example, a first FRI value triggers a 50% partial retransmission, a second FRI value triggers a 25% partial retransmission, and a third value is a full retransmission (ie, 100%). The fourth FRI value does not trigger fast retransmissions. Therefore, in this example, there are three positive FRI values and one negative FRI value.

These combinations are also possible. For example, after eNodeB sets three different partial retransmission values (possibly including 100%), each affirmative FRI value points to a corresponding quasi-static partial retransmission value (one FRI value). Does not indicate fast retransmission (ie, negative FRI value)).

In another embodiment of the present embodiment, the user equipment may include a plurality of transmitting antennas for transmitting data packets. In this case, the receiving FRI triggers the retransmission of the data packet so that the UE retransmits the data packet to the eNodeB using the plurality of transmitting antennas. That is, when the transmission includes two transport blocks (codewords) as in SU-MIMO, the affirmative FRI, as a matter of course, indicates the retransmission of both transport blocks with respect to FIG. 5, resulting in excessive PHY. It is preferable to reuse as much of the transmit buffer as possible without reprocessing. In this case, referring to FIG. 5, if the transmission buffer is reused when both transport blocks are retransmitted, it is not necessary to process the blocks shown in FIG. 5 at all. That is, since the retransmission of the two transport blocks occurs immediately after each "SC-FDMA signal generation" block, it can be transmitted directly to the eNodeB without any separate processing.

Similarly, on the eNodeB side where a plurality of antennas can be used, when the FRI that triggers the retransmission of the transport block is transmitted, the retransmitted transport block is received by the eNodeB using the plurality of receiving antennas.

However, triggering the retransmission of both transport blocks by the (single) FRI comes at the expense of radio resource efficiency and signal-to-noise ratio. Therefore, in another embodiment of the present embodiment, per FRI such that retransmission of one transport block to the eNodeB and reception of one transport block at the eNodeB are performed using a plurality of transmitting antennas. It will trigger the retransmission of one transport block. Note that in this case, more processing is required on the UE until the SC-FDMA signal is available for transmission. That is, referring to FIG. 5, when FRI triggers only the retransmission of one transport block, the processing of the "layer mapping" block is involved up to the "SC-FDMA signal generation" block.

The above description relates to retransmission behavior, which assumes that the same transport block of data is used for transmission and retransmission. That is, it implies that the retransmission applies to the same HARQ process. However, there may be multiple HARQ processes that can be scheduled simultaneously according to a synchronous or asynchronous protocol.

In either case, as shown in FIG. 7, high-speed retransmission will occur at the TTI at the time "# t_push". Therefore, for generally different HARQ processes, PUSCH transmissions at time "# t_push" may be triggered by positive FRI at time "# t_push-t2" and by DCI (or HI) at time "#". It may be triggered by "t_process-t0". Therefore, in FIG. 7, different HARQ processes P0 and P1 are shown. In the exemplary case shown in FIG. 7, the HARQ process P0 relates to the FRI start retransmission at time "# t_push", while the HARQ process P1 relates to the DCI start retransmission at time "# t_push-t0".

As further shown in FIG. 7, the retransmission of both HARQ processes P0 and P1 results in a retransmission at time "#t_push". However, in order to avoid transmission conflicts, the UE needs to decide what should be the time "# t_push". The first option is to continue retransmitting HARQ process P0. That is, it follows the FRI trigger received at the time "# t_push-t2". The second option is to continue retransmitting the HARQ process P1. That is, it follows the DCI (or HI) received at the time "# t_push-t0".

In this regard, a preferred embodiment of the present embodiment relates to a specific behavior of the UE, that is, a request to retransmit a data packet by FRI and a request to simultaneously execute another data packet to be transmitted by DCI or HI. When received, it follows the FRI request (ie, the first option described above) and ignores the DCI or HI request.

As shown in the "Background" section, if the HI and DCI collide, the UE follows the DCI and ignores the HI. However, in contrast, DCI (or HI) shall be ignored according to fast retransmissions, as provided by another embodiment of this embodiment. This is because the affirmative FRI was sent later than the DCI corresponding to the same subframe. As a result, the eNodeB should assume that if the UE attempts to follow a positive FRI rather than a DCI, it will only send a positive FRI. Otherwise, the subframe is not triggering a positive FRI retransmission.

As described above with respect to FIG. 6, even if the UE avoids transmission collisions according to FRI requirements, as shown in FIG. 7, by using the same redundant version RV # 0, by PUSCH transmission and FRI initiated by DCI. Both of the started PUSCH transmissions are executed. In other words, RV # 0 is determined by DCI start PUSCH transmission and reused by FRI start PUSCH transmission.

Further, in another variant of this embodiment, the FRI further includes a HARQ process number indicator to indicate the particular HARQ process used by the transmitter for the previous transmission of the data packet.

The table below shows UE behavior for multiple cases relating to the content of received FRI and DCI / HI.

The following table shows different UE behaviors for multiple cases relating to the contents of received FRI and DCI / HI.

With reference to the above description, according to a modification of the present embodiment, the FRI may indicate at least one of the following elements.
-Whether fast retransmission was triggered (affirmative FRI or negative FRI or NACK or ACK)
-When fast retransmission is triggered: HARQ process number indicator of the triggered retransmission-When fast retransmission is triggered: Partial retransmission parameter indicating the requested part of the data block to be retransmitted-Fast retransmission When is triggered: Instructions regarding the period t2 until the UE sends

According to another embodiment of the present embodiment, the UE receives the FRI in the radio resource used to receive the HI, receives the FRI as DCI (eg DCI format 7), or in a common search space. The FRI is received by the preset radio resource, or the FRI is received by the preset radio resource of the user device-specific search space.

In general, FRI can be transmitted by one of the following methods.
The same RE that the UE expects to discover PHICH (but a different subframe if the period t1 is shorter than the time between the PUSCH transmission and the corresponding subframe carrying the HI), ie the subframe / TTI control channel. Transmission in RE belonging to REG in the area, or transmission
-Transmission in RE belonging to the common search space of DCI, ie RE in which all UEs detect FRI: or-Transmission in DCI in which FRIs of multiple UEs and / or subframes are preferably multiplexed. For example, DCI may include four FRIs, the first FRI can be applied to UE1, the second FRI can be applied to UE2, and so on. Especially in the case of a TDD system, since it is possible to multiplex or bundle multiple FRIs into DCI for one UE, for example, the first four FRIs can be applied to the four PUSCH transmissions of UE1, the next three. The same is true for others, such as one FRI being applicable to the three PUSCH transmissions of UE2. When the FRI is multiplexed for a plurality of UEs, it is preferable that the DCI is transmitted in the common search space. If the FRI is transmitted for only one UE, it is preferred that the DCI be transmitted in a UE-specific search space.

As a modification of the present embodiment, instead of including one or more of the above contents in the FRI, one or more of the above can be used to determine the RE to which the FRI is transmitted. is there. For example, the HARQ process can also determine the RE to which the FRI will be transmitted. Then, the UE preferably monitors a plurality of FRI resources and evaluates only the FRI received at the maximum power.

As described for the plurality of variations of the above embodiment, in contrast to the HI-triggered retransmissions described in the "Background" section, affirmative FRI is an implicit or explicit change in RV with respect to retransmissions. Does not imply. However, as another variant of this embodiment, FRI-triggered retransmissions shall not affect the potential RV determination rules for non-adaptive retransmissions by PHICH. As mentioned above in the "Background" section, PHICH-triggered retransmissions switch implicitly and cyclically between RVs {0,2,3,1}. According to this variant, the affirmative FRI is ignored for the purpose of later determining the RV of the non-adaptive retransmission. That is, in RV switching / circulation, only the RV of the previous DCI / HI trigger (re) transmission shall be taken into account.

As another variant of this embodiment, in addition to using FRI as described above, if PUSCH occupies only a short TTI (discussed in the "Short Latency" discussion above) rather than the entire 1 ms TTI, then a transformer. Since the port block is smaller than the 1 ms TTI, the decoding result (OK / failure) in eNodeB can be used immediately. Therefore, in this case, it is possible to transmit the FRI faster than the DCI / HI in the conventional system.

In another embodiment of the present embodiment, the previous transmission of the data packet may be "initial transmission of the data packet" or "retransmission of the data packet".

[Hardware and software implementation of this disclosure]
Other exemplary embodiments relate to the implementation of the various embodiments described above by using hardware, software, or software associated with the hardware. In this connection, a user device (mobile terminal) is provided. User equipment is configured to perform the methods described herein, and corresponding entities such as receivers, transmitters, processors, etc. are appropriately involved in these methods.

It is also further recognized that various embodiments can be implemented or implemented using computer equipment (processors). The computer device or processor may be, for example, 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. Further, various embodiments may be executed or embodied by a combination of these devices. In particular, each functional block used in the above description of each embodiment can be realized by an LSI as an integrated circuit. These may be individually formed as chips, or one chip may be formed so as to include a part or all of the functional blocks. These may be combined with data input / output. Here, the LSI may also be referred to as an IC, a system LSI, a super LSI, or a polar super LSI, depending on the difference in the degree of integration. However, the technique for mounting an integrated circuit is not limited to LSI, and may be realized by using an individual circuit or a general-purpose processor. Further, a reconfigurable processor capable of reconfiguring the connection and setting of a circuit cell arranged inside the LSI or an FPGA (field programmable gate array) programmable after the LSI is manufactured may be used. ..

Further, various embodiments may be implemented by software modules that are executed by a processor or directly in hardware. It is also possible to combine software modules and hardware implementations. The software module may be stored in any kind of computer-readable storage medium such as RAM, EPROM, EEPROM, flash memory, registers, hard disk, CD-ROM, DVD, and the like. It should be further noted that the individual features of the various embodiments may be the subject of another embodiment, either individually or in any combination.

Of course, many modifications and / or improvements of the present disclosure are possible to those skilled in the art, as shown in certain embodiments. Therefore, it should be considered that this embodiment is merely an example in all respects and is not limited in any way.

Claims (14)

A user device that operates the transmission protocol for uplink data packet transmission in a communication system.
A receiver that operates to receive a retransmission indicator, which indicates whether or not the base station has requested the retransmission of a previously transmitted data packet.
A transmitter that operates to retransmit the data packet with the same redundant version already used for the previous transmission of the data packet when the retransmission indicator indicates affirmation of the request.
With
The retransmission indicator indicates that a portion of the previously transmitted data packet will be retransmitted.
The transmitter uses the transmit power so that the transmit power of the retransmission of the part of the previously transmitted data packet is equal to the total transmit power of the previously transmitted data packet. User device. The retransmission indicator indicates that the retransmission is performed with the same additional transmission parameters that were used for the previous transmission of the data packet.
The user of claim 1, wherein the transmitter further operates to retransmit the data packet with the same additional transmission parameters as those used for the previous transmission of the data packet. machine. The user device of claim 2, wherein the same additional transmission parameter used to retransmit the data packet is at least a scramble code of the previously transmitted data packet. Some of the previously transmitted data packets are 50% or 25% of the previously transmitted data packets.
Any of claims 1-3, in which 50% of the data packet is used in the use of the retransmission transmission power, the transmission power of the part of the previously transmitted data packet is doubled. The user device described in paragraph 1. The receiving unit further operates to receive the retransmission indicator at the first timing after the transmission of the previously transmitted data packet, and the first timing is fixed or the base station. The user device according to any one of claims 1 to 4, which can be set quasi-statically according to the above. The transmitter further operates to transmit the retransmission of the data packet at a second timing after the receiver receives the retransmission indicator.
The second timing is any one of claims 1 to 5, which is fixed, can be set quasi-statically by the base station, or is variable based on each information contained in the reception / retransmission indicator. The user equipment described in the section. Retransmission of data packets can also be triggered by downlink control information called DCI and / or HARQ indicators called HI.
A first period between the previous transmission of the data packet and the reception of the retransmission indicator, and / or a second period between the reception of the retransmission indicator and the retransmission of the data packet. The period of is shorter than the third period between the reception of DCI or HI and the corresponding retransmission of the data packet, and at least one of the first period and the second period is shorter than 4 ms. , The user device according to any one of claims 1 to 6. When the receiving unit receives a request for executing the retransmission of the data packet by the retransmission indicator and a request for executing the transmission of another data packet by the DCI or HI at the same time, the transmitting unit receives the request for executing the transmission of another data packet at the same time. The user device according to claim 7, further operating in accordance with the request by the transmission indicator and ignoring the request by the DCI or HI. The user device according to any one of claims 1 to 8, wherein the retransmission indicator further includes a HARQ process number indicator indicating the HARQ process used by the transmitter for the previous transmission of the data packet. The user device according to any one of claims 1 to 9, wherein the previous transmission of the data packet is an initial transmission or retransmission of the data packet. The receiver either receives the retransmission indicator in a radio resource used to receive a HARQ indicator called HI, receives the retransmission indicator as a DCI, or in a preset radio resource in a common search space. The one according to any one of claims 1 to 10, wherein the retransmission indicator is received, or the retransmission indicator is further operated to receive the retransmission indicator in a preset radio resource of a user device-specific search space. User equipment. When the user equipment uses multiple transmitting antennas to transmit data packets,
The receiver further operates to receive the retransmission indicator that triggers the retransmission of the data packet.
The transmitter further operates to retransmit the data packet to the base station using the plurality of transmitting antennas.
Or
The receiver further operates to receive the retransmission indicator that triggers the retransmission of one of the data packets.
The user according to any one of claims 1 to 11, wherein the transmitting unit further operates so as to retransmit the one of the data packets to the base station using the plurality of transmitting antennas. machine. A base station that operates the transmission protocol for uplink data packet transmission in communication systems.
A transmitter that operates to transmit a retransmission indicator, which indicates to the user device whether or not a previously transmitted data packet is required to be resent.
When the retransmission indicator indicates affirmation of the request, the user equipment receives from the user equipment the same redundant version of the retransmission data packet that has already been used for the previous transmission of the data packet. With a receiver that works like
With
The retransmission indicator indicates that a portion of the previously transmitted data packet will be retransmitted.
In the user equipment, the receiving unit transmits so that the transmission power of the retransmission of the part of the previously transmitted data packet is equal to the total transmission power of the previously transmitted data packet. A base station that receives the retransmitted data packet for which power has been used. A method of operating the transmission protocol of uplink data packet transmission in a communication system in a user device.
A step of receiving a retransmission indicator, which indicates whether the base station has requested the retransmission of previously transmitted data packets.
A step of retransmitting the data packet with the same redundant version already used for the previous transmission of the data packet when the retransmission indicator indicates affirmation of the request.
Including
The retransmission indicator indicates that a portion of the previously transmitted data packet will be retransmitted.
The step of retransmitting the data packet transmits such that the transmission power of the retransmission of the part of the previously transmitted data packet is equal to the total transmission power of the previously transmitted data packet. Methods, including using electricity.

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