WO2018138905A1 - Base station, wireless terminal, wireless communication system, and wireless communication method - Google Patents

Abstract

A base station (110) is provided with: a transmission unit for generating transmission data in which first data is multiplexed at a timing that temporally precedes second data having higher allowance for a delay than does the first data, and transmitting the transmission data to a wireless terminal (120), by a wireless resource used in time-division-duplexed (TDD) communication with the wireless terminal (120); and a reception unit for receiving first response information from the wireless terminal (120) that received the transmission data, the first response information indicating that the first data was successfully received or could not be received, or indicating that the first data was successfully decoded or could not be decoded, by the wireless resource.

Description

Base station, wireless terminal, wireless communication system, and wireless communication method

The present invention relates to a base station, a wireless terminal, a wireless communication system, and a wireless communication method.

Self-contained TDD Subframe is being studied in the fifth generation (Fifth Generation; 5G) mobile communications, whose specifications are being developed by the Third Generation Partnership Project (3GPP). Note that TDD is an abbreviation for Time Division Duplex. Hereinafter, Self-contained TDD may be referred to as “built-in TDD”.

In the built-in TDD, the same radio resource can be shared between the data and the Automatic Repeat Request (ARQ) response.

For example, Long Term Evolution (LTE) or LTE-Advanced (LTE-A) (hereinafter referred to as “LTE” in some cases) whose specifications are defined by 3GPP realizes simultaneous transmission and reception. As one of the communication methods, TDD is adopted. In TDD adopted in LTE, a wireless terminal can make a Hybrid ARQ (HARQ) response at the timing of an Uplink (UL) subframe. In other words, in TDD, HARQ RoundRTrip Time (RTT) depends on the position of the UL subframe.

On the other hand, in the built-in TDD subframe, since the wireless terminal can transmit the HARQ response without waiting for the UL subframe, the latency can be reduced, and the uplink / downlink (UL / DL) ratio and delay are reduced. And can be separated.

As described above, in the built-in TDD subframe, since the wireless terminal can transmit ACK or NACK of the data at the end of the wireless resource that has received the data, until the ACK or NACK is transmitted after the data is received Can be made shorter than TDD. Note that ACK or NACK (hereinafter sometimes referred to as “ACK / NACK” or simply “ACK”) is an example of information indicating reception success or reception failure, or decoding success or decoding failure.

However, since the ACK / NACK determination by the wireless terminal is performed using the block decoding processing result of the received data, the wireless terminal transmits ACK / NACK within the transmission time of the ACK response depending on the time required for the block decoding processing. It may be difficult to determine.

In one aspect, an object of the present invention is to efficiently secure a time from reception of data by a wireless terminal to transmission of information indicating reception success or reception failure, or decoding success or decoding failure.

In addition, the present invention is not limited to the above-described object, and other effects of the present invention can be achieved by the functions and effects derived from the respective configurations shown in the embodiments for carrying out the invention which will be described later. It can be positioned as one of

In one aspect, the base station may include a transmission unit and a reception unit. The transmission unit generates transmission data obtained by multiplexing the first data at a timing that precedes the second data in radio resources used for time division duplex (TDD) communication with the radio terminal. The transmission data may be transmitted to the wireless terminal. The second data may be data having a higher delay tolerance than the first data. In addition, the reception unit receives first response information indicating successful reception or reception failure of the first data or successful decoding or decoding failure in the wireless resource from the wireless terminal that has received the transmission data. You may receive it.

In one aspect, it is possible to efficiently secure the time from data reception by the wireless terminal to transmission of information indicating reception success or reception failure, or decoding success or decoding failure.

It is a block diagram which shows the structural example of the radio | wireless communications system which concerns on one Embodiment. It is a figure which shows an example of a built-in type TDD sub-frame. It is a figure explaining the guard time in a built-in type TDD sub-frame. It is a figure which shows an example of the data which a delay is accept | permitted. It is a figure which shows an example of the data which a delay is accept | permitted. It is a figure which shows an example of the data structure of control information. It is a figure which shows an example of a sequence in case an ACK response timing is notified using downlink control information. It is a figure which shows an example of a sequence in case ACK response timing is notified by alerting | reporting information previously. It is a block diagram which shows the function structural example of the wireless base station which concerns on one Embodiment. It is a block diagram which shows the hardware structural example of the wireless base station which concerns on one Embodiment. It is a block diagram which shows the function structural example of User Equipment (UE) concerning one Embodiment. It is a block diagram which shows the hardware structural example of UE which concerns on one Embodiment. It is a flowchart which shows the operation example of the scheduling process by a wireless base station. It is a flowchart which shows the operation example of the baseband process by a wireless base station. It is a flowchart which shows the operation example of the reception process by UE. It is a flowchart which shows the operation example of the transmission process by UE. It is a figure which shows the example which transmits UL data, after UE receives low delay data.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described below. For example, the present embodiment can be implemented with various modifications without departing from the spirit of the present embodiment.

In the drawings used in the following embodiments, the same reference numerals denote the same or similar parts unless otherwise specified.

[1] One Embodiment [1-1] Configuration Example of Radio Communication System FIG. 1 is a block diagram illustrating a configuration example of a radio communication system 100 according to an embodiment. As illustrated in FIG. 1, the radio communication system 100 according to an embodiment may include, for example, a radio base station 110, a User Equipment (UE) 120, and a host device 130. Note that the radio communication system 100 may include a plurality of radio base stations 110, and may include a plurality of UEs 120.

The radio communication system 100 performs radio communication according to a predetermined radio communication method between the radio base station 110 and the UE 120. For example, the wireless communication method may be a wireless communication method of the fifth generation or later, or may be an existing wireless communication method such as LTE / LTE-A or Worldwide Interoperability for Microwave Access (WiMAX). As an example, in the following description, it is assumed that the wireless communication method is a wireless communication method using a fifth generation built-in TDD subframe.

The wireless base station 110 is an example of a base station or a first wireless communication device. As the radio base station 110, for example, a radio signal connected to a macro base station, a micro base station, a femto base station, a pico base station, a metro base station, a home base station, or a Centralized Radio Access Network (C-RAN) It may be a transmission / reception device. Examples of the radio signal transmitting / receiving device include Remote Radio Equipment (RRE), Remote Radio Head (RRH), and the like.

When a radio signal transmitting / receiving apparatus is used as the radio base station 110, the radio base station 110 is connected to each of the radio base stations 110 at any position of the radio base station 110 shown in FIG. There may be a data processing device. The data processing device performs various processes on data transmitted from the wireless signal transmitting / receiving device or data received by the wireless signal transmitting / receiving device. Examples of the data processing device include Baseband Unit (BBU). In this case, the function as the radio base station 110 may be distributed in both the data processing device and the radio signal transmitting / receiving device.

The radio base station 110 may form or provide a radio area. The wireless area may include a “virtual wireless area” that handles a plurality of wireless areas as one virtual wireless area. A radio area may be a cell or a sector. The cell may include a cell such as a macro cell, a micro cell, a femto cell, a pico cell, a metro cell, or a home cell. The cell is formed according to a range in which the radio wave transmitted by the radio base station 110 can be received by the UE 120 with the required quality (for example, a range that can satisfy the required radio channel quality, which may be referred to as coverage). It is an example of a wireless area.

The term “cell” means an individual geographical area in which the radio base station 110 provides radio services, and is managed by the radio base station 110 in order to communicate with the UE 120 in the individual geographical area. It may also mean part of the function. In the following description, the function or operation of the radio base station 110 may be described as a function or operation of a cell formed or provided by the radio base station 110 in some cases.

The radio base station 110 may relay communication between the UE 120 and the upper apparatus 130 or between the UEs 120 by performing radio communication with the UE 120. The radio communication may be performed using radio resources allocated from the radio base station 110 to the UE 120. The radio resource may be a resource related to time and frequency. The radio base station 110 may be connected to the higher-level device 130 via, for example, an S1 interface.

UE 120 is an example of a wireless terminal or a second wireless communication device. Examples of the UE 120 include a mobile station having a wireless communication function, such as a mobile phone such as a smartphone, a movable personal computer (PC) such as a tablet terminal, a laptop, or a data communication device such as a mobile router. The mobile station may be attached to a moving body such as a vehicle and move. In addition to these mobile stations, UE 120 may be a device such as a sensor (including an Integrated Circuit (IC) chip) having a wireless communication function.

The host device 130 is an example of a control device. Examples of the host device 130 include at least one of MME, SGW, and other control or management nodes. “MME” is an abbreviation for Mobility Management Entity. For example, the wireless base station 110 may be accommodated and Network Control Control Plane (C-plane) processing may be performed. “SGW” is an abbreviation for Serving Gateway, and for example, User Plane (U-plane) data (user data) may be processed.

The host device 130 may exist in the host network 140. Examples of the upper network 140 include a wired network in which packet communication is performed. The packet communication may be, for example, Internet （Protocol (IP) packet communication. The wired network may be referred to as a packet core network such as Evolved Packet Core (EPC).

[1-2] Description of an Embodiment Next, a method according to an embodiment will be described with reference to FIGS.

FIG. 2 shows DL transmission data transmitted from the radio base station 110 to the UE 120 and UL ACK / NACK transmitted from the UE 120 to the radio base station 110 as an example of the built-in TDD subframe. A Guard-Period (GP) may be provided between DL transmission data and UL ACK / NACK. GP is an example of a region for preventing interference between separate signals (eg, DL signal and UL signal). Note that a period corresponding to GP may be realized by timing control by the radio base station 110 or the UE 120, and in this case, the GP may not be provided.

In the example of FIG. 2, DL transmission data and UL ACK / NACK are transmitted using temporally continuous radio resources in the same frequency band, where the vertical axis represents the frequency band and the horizontal axis represents time. Show the state.

In the DL transmission data, “address headers” including a destination address, “DL Control” which is an example of control information including scheduling information, and data to be transmitted, for example, “Data” including user data are mapped. Has been. Note that Reference Signal (RS) as an example of a reference signal may be mapped to the position of “address headers”. Upon receiving the DL transmission data from the radio base station 110, the UE 120 demodulates and decodes “Data” using the scheduling information included in “DL Control”, and determines the ACK / ID determined using the demodulation or decoding processing result. NACK is transmitted to UE120.

Note that ACK is an example of response information indicating reception success or decoding success, and NACK is an example of response information indicating reception failure or decoding failure. In addition, ACK or NACK transmitted from the UE 120 to the radio base station 110 is an example of response information indicating reception success or reception failure, or decoding success or decoding failure.

As illustrated in FIG. 3, the ACK / NACK determination by the UE 120 is performed using the data demodulation or decoding result as described above. However, since the UE 120 performs demodulation and decoding (for example, block decoding) processing after receiving data (or in parallel), it is difficult to transmit an ACK response to the radio base station 110 immediately after receiving data. In 5G mobile communication, in a built-in TDD time slot, the time from DL transmission data to ACK is assumed to be about 100 to 200 μs (microseconds).

Therefore, as illustrated in FIG. 3, it is conceivable to increase the guard time in order to secure the processing time from the reception of data by the UE 120 to the ACK response. In addition, guard time may be the period for which GP occupies the time direction of radio resources, for example.

However, in this case, the guard time is unduly long, and data or the like is not transmitted during the guard time, which may impair the utilization efficiency of radio resources.

Therefore, the wireless communication system 100 according to an embodiment may perform the processing exemplified below.

For example, the radio base station 110 generates transmission data in which the first data is multiplexed at a timing that precedes the second data in radio resources used for time division duplex (TDD) communication with the UE 120. Then, the transmission data may be transmitted to the UE 120. The second data may be data having a higher delay tolerance than the first data.

In addition, the UE 120 may transmit, to the radio base station 110, the first response information indicating the reception success or reception failure of the first data or the decoding success or the decoding failure in the radio resource.

Thereby, the time from when the UE 120 receives the first data of the transmission data to when the first response information is transmitted to the radio base station 110 can be used for the transmission of the second data. In other words, at least a part of the guard time provided for securing the processing time from the reception of the first data by the UE 120 to the transmission of the first response information is set as the second data. Can be used for transmission.

Further, since the second data is data having a higher delay tolerance than the first data, the UE 120 performs a process of transmitting the first response information to the radio base station 110 in response to the second data. This can be performed with priority over the process of transmitting information to the radio base station 110.

Therefore, the time until the ACK response by the UE 120 can be secured, and the design can be facilitated. In addition, it is possible to effectively use free resources until the ACK response after receiving the first data.

The downlink transmission data from the radio base station 110 to the UE 120 may be data obtained by time division multiplexing (TDM) of the first data and the second data, and the first data, the second data, May be data obtained by spatially multiplexing (Spatial Mulplexing).

When time division multiplexing is used as the multiplexing scheme, the UE 120 may transmit the first response information to the radio base station 110 after the time division multiplexing timing of the second data of the transmission data.

When spatial multiplexing is used as the multiplexing scheme, the UE 120 may transmit the first information to the radio base station 110 at a timing that precedes the spatial multiplexing timing of the second data of the transmission data. Thus, in the case of spatial multiplexing, UE 120 may receive the second data after receiving the first data and performing an ACK response.

By the way, as described above, the built-in TDD subframe is considered as one of the methods for achieving separation of the UL / DL ratio and the delay in 3GPP. It is also positioned as one.

(A) To provide a frame format that can cover all license / unlicensed bandwidth, Massive MIMO, and D2D methods.

Note that MIMO is an abbreviation for Multiple-Input and Multiple-Output, and D2D is an abbreviation for Device to Device.

(B) Realize low delay in the application layer.

These can be achieved by the following advantages of the built-in TDD subframe, for example.

(A) Resource management is facilitated by sharing the same radio resource between the data and the ARQ response.

In LTE, the HARQ ACK response corresponding to PDSCH is transmitted on PUCCH (associated with the PDCCH resource that scheduled PDSCH) or PUSCH (when UL-SCH is scheduled) after 4 subframes. Thus, the specification that the PDSCH assigned to the independent radio resource based on a certain rule is associated with the HARQ ACK response is complicated, which hinders implementation and specification expansion. Therefore, resource management can be facilitated by adopting a frame format that shares the same radio resource with the ARQ response.

PDSCH is an abbreviation for Physical Downlink Shared Channel, and PUCCH is an abbreviation for Physical Uplink Control Channel. PDCCH is an abbreviation for PhysicalPhysDownlink Control Channel, PUSCH is an abbreviation for Physical Uplink Shared Channel, and UL-SCH is an abbreviation for Uplink Shared Channel.

(B) RS becomes on-demand transmission and the overhead of the entire system can be reduced.

In LTE, a base station transmits a Cell-specific Reference Signal (C-RS) over the entire band in subframes other than the Multicast-Broadcast Single-Frequency Network (MBSFN) subframe, and the terminal transmits this C-RS. To perform demodulation. According to the built-in TDD subframe, since UE-specific RS is transmitted in the same frame, overhead due to transmission / reception of cell common information including C-RS can be reduced.

Thus, the built-in TDD subframe has advantages of easy resource management and reduced delay of the entire system.

From the above, according to the wireless communication system 100 according to the embodiment, it is possible to efficiently secure the time from the data reception by the UE 120 to the ACK response while taking advantage of the above-described built-in TDD subframe.

[1-2-1] First and Second Data As described above, the second data is data having a higher delay tolerance than the first data. For example, the first data may be low-delay data that requires a low delay for the ACK response, and the second data may be delay-allowed data that allows a delay of the ACK response. As described above, it can be understood that the low delay data is arranged in the first half and the delay allowable data is arranged in the second half in the radio resource.

(First example of delay tolerance data)
As a first example of delay tolerance data, common information for which an ACK response is not required may be used as shown in FIG. Examples of common information for which an ACK response is not required include broadcast information such as System Information Block (SIB) and RS.

As illustrated in FIG. 4, when common information is used as the second data, “Data” that is an example of the first data and an example of the second data are included in the transmission data from the radio base station 110. “BCH” may be time-division multiplexed. BCH is an abbreviation for Broadcast Channel.

In 3GPP, in order to reduce congestion of wireless traffic in 5G mobile communication, it is considered to stop or restrict common notification of information such as RS to a plurality of wireless terminals. In this case, it is conceivable that the radio base station 110 individually transmits common information such as SIB and RS to the UE 120 periodically, at a specific timing, or on demand. Therefore, in the example of FIG. 4, such common information may be used as the second data.

In the example of FIG. 4, “RS” exists at the head of the downlink transmission data, but the RS may be mapped to one or both of “RS” and “BCH”. RSs may be grouped according to applications such as calculation of phase noise and calculation of Channel State Information (CSI).

In the example of FIG. 4, the UE 120 may demodulate “Data” which is an example of the first data, and may perform decoding when the demodulation is completed. Note that demodulation may be performed on a symbol-by-symbol basis, for example, at the reception timing of an Orthogonal Frequency Division Multiplexing (OFDM) symbol.

Then, the UE 120 determines reception success or reception failure using the demodulation result, or decoding success or decoding failure using the decoding result, and transmits ACK / NACK to the radio base station 110 at the first timing. Good.

(Second example of delay tolerance data)
As a second example of the delay tolerance data, as shown in FIG. 5, a Radio Access Bearer (RAB) that does not require an extremely low delay may be used. Examples of RAB include Signaling Radio Bearer (SRB), voice, and the like.

As illustrated in FIG. 5, when RAB (for example, information transmitted by RAB) is used as the second data, the transmission data from the radio base station 110 includes “VLL Data that is an example of the first data. ”And“ non VLL Data ”which is an example of the second data may be time-division multiplexed. VLL is an abbreviation for Very Low Latency.

In the example of FIG. 5, the UE 120 may demodulate “VLLVData”, which is an example of the first data, as in the example of FIG. 4, and may perform decoding when the demodulation is completed.

Then, as in the example of FIG. 4, the UE 120 determines reception success or reception failure using the demodulation result, or decoding success or decoding failure using the decoding result, and is addressed to the radio base station 110 at the first timing. ACK / NACK may be transmitted to

Also, the UE 120 may demodulate “non-VLL data” which is an example of the second data, and may perform decoding when the demodulation is completed. The demodulation of “non「 VLL Data ”may be performed on a symbol-by-symbol basis like“ VLL Data ”, and may be performed in parallel with the decoding of“ VLL Data ”in at least some time intervals. .

Then, the UE 120 determines reception success or reception failure using the demodulation result, or decoding success or decoding failure using the decoding result, and transmits ACK / NACK to the radio base station 110 at the second timing. Good.

[1-2-2] ACK response timing The first timing at which the ACK of the first data is returned, the fact that the ACK of the second data is not required (example in FIG. 4), and the ACK of the second data At least one of the second timings of returning (example in FIG. 5) may be notified by the following method (i) or (ii).

(I) The radio base station 110 notifies the UE 120 by “Control”, which is an example of control information.

FIG. 6 is a diagram showing an example of the data structure of the control information. As illustrated in FIG. 6, for example, “common information”, “low delay data control information”, and “delayable data control information” may be set in the control information from the beginning of the data. The control information may be set for each subframe of Transmission の Time Interval (TTI).

“Common information” may include control information common to all data, for example, the presence / absence of low-delay data, the presence / absence of delay-tolerant data, the time length of the corresponding channel, or the number of symbols.

When low-delay data is transmitted, “low-delay data control information” may be multiplexed with downlink control information. “Low-delay data control information” includes the transmission block size of low-delay data, modulation schemes such as Phase-Shift Keying (PSK) and Quadrature Amplitude Modulation (QAM), spatial multiplexing schemes and parameters, and ACK for low-delay data Information such as response resources may be included. In other words, “low delay data control information” is an example of first control information indicating the first transmission timing for the first response information.

“When delay tolerance data is transmitted,“ delay tolerance data control information ”may be multiplexed with the downlink control information. The “delay allowable data control information” may include information such as a transmission block size of delay allowable data, a modulation scheme such as PSK and QAM, a spatial multiplexing scheme and spatial multiplexing parameters, and an ACK response resource of delay allowable data. In other words, the “delayable data control information” is an example of second control information indicating the second transmission timing for the second response information.

FIG. 7 shows an example of a sequence when ACK response timing is notified using downlink control information. For example, the UE 120 makes a radio link connection establishment request to the radio base station 110 and notifies an ACK response delay time (process A1). The radio base station 110 performs radio link establishment setting for the UE 120 (process A2).

The wireless link connection establishment request may be, for example, a Random Access Preamble in a Random Access (RA) procedure. The ACK response possible delay time may be, for example, the shortest delay time from when UE 120 receives downlink transmission data until it returns an ACK response, or may be information indicating the processing performance of UE 120 . The ACK response possible delay may be included in the information transmitted in the procedure of establishing the radio link connection, or may be notified from the UE 120 to the radio base station 110 separately from such information.

When the downlink data addressed to the UE 120 is generated, the radio base station 110 transmits the downlink data to the UE 120, and notifies the UE 120 of the ACK response delay time using the control information (Processing A3). The UE 120 transmits an ACK response according to the ACK response time notified from the radio base station 110 (process A4).

(Ii) The UE 120 is notified in advance from the radio base station 110.

“Preliminary notification” may include at least one of notification based on control information of a subframe before downlink transmission data including first data, and notification in predetermined communication. . The “predetermined communication” includes, for example, processing for the UE 120 to connect to the radio base station 110, for example, communication in a random access procedure between the radio base station 110 and the UE 120, a radio resource control (RRC) connection procedure, or the like. Related communications may be included.

FIG. 8 shows an example of a sequence when the ACK response timing is notified in advance by broadcast information. For example, the radio base station 110 transmits broadcast information to the UE 120 and notifies the ACK response delay time (process B1). The radio base station 110 transmits downlink data to the UE 120 (process B2).

UE 120 transmits an ACK response according to the ACK response time notified by the broadcast information (processing B3).

[1-3] Configuration Examples of Each Device Next, configuration examples of each of the radio base station 110 and the UE 120 according to an embodiment will be described with reference to FIGS. 9 to 12. Note that the radio base station 210 shown in FIG. 9 and the radio base station 310 shown in FIG. 10 are examples of the radio base station 110 shown in FIG. Moreover, UE220 shown in FIG. 11 and UE320 shown in FIG. 12 are examples of UE120 shown in FIG. 1, respectively.

[1-3-1] Configuration Example of Base Station As shown in FIG. 9, the radio base station 210 illustratively includes an antenna 211, a radio frequency (RF) receiving unit 212, a baseband receiving unit 213, and a scheduling unit 214. , A line termination unit 215, a baseband transmission unit 216, and an RF transmission unit 217 may be provided.

The antenna 211 is an example of an interface that transmits and receives radio signals to and from the UE 220. For example, the antenna 211 may receive a UL radio signal transmitted from the UE 220 and output the received UL radio signal to the RF reception unit 212. The antenna 211 may transmit a DL radio signal (for example, a modulated signal) input from the RF transmission unit 217 to the UE 220. Note that the antenna 211 may be provided separately for reception and transmission.

The RF reception unit 212 performs a predetermined reception process on the UL reception signal to generate an uplink carrier-removed signal, and outputs the generated signal to the baseband reception unit 213. The reception processing may include, for example, low noise amplification of the received signal, frequency conversion (down conversion) to a baseband frequency, gain adjustment, demodulation, and the like.

Baseband reception section 213 performs baseband reception processing on the signal from which the upstream carrier wave has been removed from the upstream reception signal by RF reception section 212, and outputs the reception signal obtained by the baseband reception processing to line termination section 215. To do. For example, the baseband reception process may include decoding using uplink scheduling information notified from the scheduling unit 214.

The scheduling unit 214 generates uplink scheduling information and downlink scheduling information by using the radio channel quality with the UE 220 or the like acquired from the UE 220 or measured by the radio base station 210. The uplink scheduling may include radio resources used for uplink data transmission, a modulation scheme, a coding rate, and the like. The downlink scheduling information may include information indicating the UE 220 selected by the radio base station 210 as a communication destination, radio resources used for downlink data transmission, a modulation scheme, a coding rate, and the like.

The line termination unit 215 terminates the connection with the wireless network or the wired network. The wired network may include an upper network such as an S1 line (for example, the upper network 140 in FIG. 1), a network between the wireless base station 210 such as an X2 line, and the like.

For example, the line termination unit 215 may transmit the reception signal input from the baseband reception unit 213 to a higher-level network that is a destination or a destination of the reception signal. In addition, the line termination unit 215 may output the transmission signal addressed to the UE 220 received from the upper network to the baseband transmission unit 216.

The baseband transmission unit 216 performs baseband transmission processing on the transmission signal input from the line termination unit 215, and outputs a downlink baseband signal obtained by the baseband transmission processing to the RF transmission unit 217. For example, the baseband transmission process may include encoding using downlink scheduling information notified from the scheduling unit 214.

In one embodiment, the baseband transmission unit 216 may generate and map low-delay data and delay-acceptable data for the built-in TDD subframe using the scheduling information notified from the scheduling unit 214.

The RF transmitter 217 performs a predetermined transmission process on the downlink baseband signal to generate a downlink modulated signal, and outputs the generated downlink modulated signal to the antenna 211. The transmission processing may include, for example, signal modulation, frequency conversion to radio frequency (up-conversion), power amplification, and the like.

At least one of the scheduling unit 214, the line termination unit 215, the baseband transmission unit 216, and the RF transmission unit 217 described above is an example of the transmission unit 218 that performs processing of the transmission system of the radio base station 110 according to an embodiment. is there. The transmission unit 218 generates transmission data obtained by multiplexing the first data at a timing that precedes the second data in the radio resource used for time division duplex (TDD) communication with the UE 120, The transmission data may be transmitted to UE 120.

In addition, at least one of the RF reception unit 212, the baseband reception unit 213, and the scheduling unit 214 described above is an example of the reception unit 219 that performs processing of the reception system of the radio base station 110 according to an embodiment. The receiving unit 219 may receive, from the UE 120 that has received the transmission data, first response information indicating whether the first data has been successfully received or received, or whether the decoding has succeeded or failed in the radio resource.

Next, a hardware configuration example of the radio base station 310 will be described with reference to FIG. As illustrated in FIG. 10, the radio base station 310 illustratively includes an antenna 311, an RF circuit 312, an integrated circuit (IC) 313, a processor 315, storage areas 314 and 316, and a network interface (IF) 317. It's okay.

The antenna 311 is an example of the antenna 211 shown in FIG. 9, and may transmit and receive radio signals to and from the UE 320 (see FIG. 12). The RF circuit 312 is an example of the RF reception unit 212 and the RF transmission unit 217 illustrated in FIG. Note that the RF circuit 312 may be provided separately for the RF receiver 212 and the RF transmitter 217.

The IC 313 is an example of the baseband receiving unit 213 and the baseband transmitting unit 216 shown in FIG. The processor 315 is an example of the scheduling unit 214 and the line termination unit 215 illustrated in FIG.

The IC 313 and the processor 315 may perform various controls and calculations. Examples of the IC 313 and the processor 315 include an integrated circuit (IC) such as a CPU, MPU, DSP, ASIC, or FPGA. CPU is an abbreviation for Central Processing Unit, MPU is an abbreviation for Micro Processing Unit, and DSP is an abbreviation for Digital Signal Processor. ASIC is an abbreviation for Application Specific Integrated Circuit, and FPGA is an abbreviation for Field Programmable Gate Array.

Storage areas 314 and 316 are examples of hardware used for the IC 313 and the processor 315, respectively, for storing various data such as control information and user data, and information such as programs. For example, at least one of a volatile memory and a nonvolatile memory may be used as the storage areas 314 and 316, respectively. Examples of the volatile memory include Random Access Memory (RAM). Examples of the non-volatile memory include Read Only Memory (ROM), flash memory, Electrically Erasable Programmable Read-Only Memory (EEPROM), and the like.

The network IF 317 is an example of a communication interface that performs connection and communication control with a host network (for example, the host network 140 in FIG. 1), and transmits and receives signals to and from the host device 130 (see FIG. 1). You can do it.

For example, the IC 313 and the processor 315 can implement the functions of the radio base station 210 shown in FIG. 9 by executing the programs stored in the storage areas 314 and 316, respectively.

[1-3-2] Configuration Example of Radio Terminal As shown in FIG. 11, the UE 220 illustratively includes an antenna 221, an RF reception unit 222, a baseband reception unit 223, a layer 2 processing unit 224, and a baseband transmission unit. 225 and an RF transmitter 226 may be provided.

The antenna 221 is an example of an interface that transmits and receives radio signals to and from the radio base station 210. For example, the antenna 221 may receive a DL radio signal transmitted from the radio base station 210 and output the received DL radio signal to the RF receiver 222. The antenna 221 may transmit a UL radio signal (for example, a modulated signal) input from the RF transmission unit 226 to the radio base station 210. Note that the antenna 221 may be provided separately for reception and transmission.

The RF reception unit 222 performs a predetermined reception process on the DL reception signal, generates a signal after removing the downlink carrier wave, and outputs the generated signal to the baseband reception unit 223. The reception processing may include, for example, low noise amplification of the received signal, frequency conversion (down conversion) to a baseband frequency, gain adjustment, demodulation, and the like.

The baseband reception unit 223 performs baseband reception processing on the signal from which the downlink carrier wave has been removed from the downlink reception signal by the RF reception unit 222, and the reception signal obtained by the baseband reception processing is sent to the layer 2 processing unit 224. Output. For example, the baseband reception process may include decoding using downlink scheduling information. The downlink scheduling information may be included in the control information of data received from the radio base station 210, for example.

The layer 2 processing unit 224 performs various processes related to layer 2. As an example, the layer 2 processing unit 224 may perform processing related to a Medium Access Control (MAC) layer related to radio resource allocation, HARQ retransmission control, and the like. For example, the layer 2 processing unit 224 may determine ACK / NACK or the like using the received signal or the like input from the baseband receiving unit 223. Further, the layer 2 processing unit 224 may exchange the received reception signal and the transmission signal to be transmitted with the processor 325 of the UE 220 (see FIG. 12). The transmission signal may include user data and various control information (for example, ACK response).

The baseband transmission unit 225 performs baseband transmission processing on the transmission signal input from the layer 2 processing unit 224 and outputs an uplink baseband signal obtained by the baseband transmission processing to the RF transmission unit 226. For example, the baseband transmission process may include encoding using uplink scheduling information. The uplink scheduling information may be included in the control information of data received from the radio base station 210, for example.

The RF transmission unit 226 performs predetermined transmission processing on the uplink baseband signal to generate an uplink modulated signal, and outputs the generated uplink modulated signal to the antenna 221. The transmission processing may include, for example, signal modulation, frequency conversion to radio frequency (up-conversion), power amplification, and the like.

At least one of the RF reception unit 222 and the baseband reception unit 223 described above is an example of the reception unit 228 that performs processing of the reception system of the UE 120 according to an embodiment. The receiving unit 228, in the radio resource used for time division duplex (TDD) communication with the radio base station 110, transmission data obtained by multiplexing the first data at a timing temporally preceding the second data, You may receive from the wireless base station 110. FIG.

Further, at least one of the baseband transmission unit 225, the RF transmission unit 226, and the layer 2 processing unit 224 described above is an example of the transmission unit 229 that performs processing of the transmission system of the UE 120 according to an embodiment. The transmission unit 229 may transmit, to the radio base station 110, the first response information indicating the reception success or reception failure of the first data, or the decoding success or the decoding failure in the radio resource.

Next, a hardware configuration example of the UE 320 will be described with reference to FIG. As shown in FIG. 12, the UE 320 may illustratively include an antenna 321, an RF circuit 322, an IC 323, a processor 325, and storage areas 324 and 326.

The antenna 321 is an example of the antenna 221 shown in FIG. 11 and may transmit and receive a radio signal to and from the radio base station 310. The RF circuit 322 is an example of the RF receiver 222 and the RF transmitter 226 shown in FIG. Note that the RF circuit 322 may be provided separately for the RF receiver 222 and the RF transmitter 226.

The IC 323 is an example of the baseband receiving unit 223 and the baseband transmitting unit 225 shown in FIG. The processor 325 is an example of the layer 2 processing unit 224 illustrated in FIG.

The IC 323 and the processor 325 may perform various controls and operations, respectively. Examples of the IC 323 and the processor 325 include an integrated circuit (IC) such as a CPU, MPU, DSP, ASIC, or FPGA, respectively.

Storage areas 324 and 326 are examples of hardware used for the IC 323 and the processor 325, respectively, for storing various data such as control information and user data, and information such as programs. As the storage areas 324 and 326, for example, at least one of a volatile memory and a nonvolatile memory may be used, respectively. Examples of the volatile memory include a RAM. Examples of the non-volatile memory include ROM, flash memory, EEPROM, and the like.

For example, the IC 323 and the processor 325 can implement the functions of the UE 220 shown in FIG. 11 by executing the programs stored in the storage areas 324 and 326, respectively.

[1-4] Operation Example Next, with reference to FIG. 13 to FIG. 16, an operation example of the radio communication system 100 configured as described above will be described. This will be described using a configuration example.

[1-4-1] Scheduling Process As illustrated in FIG. 13, the scheduling unit 214 of the radio base station 210 acquires a transmission buffer size for each user (for example, UE 220) from the baseband transmission unit 216. Then, scheduling section 214 extracts UE 220 having a transmission buffer size larger than “0”, in other words, UE 220 having data to be transmitted as a scheduling target (step P11). In the transmission buffer, for example, the line termination unit 215 may store, for each user, data or the like destined for the user.

The scheduling unit 214 selects the UE 220 to be transmitted from the extracted UE 220 at the corresponding timing (Step P12). Examples of the selection method of the UE 220 include selection based on round robin and selection based on Proportional Fairness (PF).

The scheduling unit 214 determines scheduling parameters related to the transmission block size of low delay data, modulation scheme, coding rate, and the like based on the buffer size of low delay data for the selected UE 220 (step P13).

Further, the scheduling unit 214 determines scheduling parameters related to the transmission block size of the delay allowable data, the modulation scheme, the coding rate, and the like based on the buffer size of the delay allowable data for the selected UE 220 (Step P14).

Then, the scheduling unit 214 notifies the baseband transmission unit 216 of scheduling information including the scheduling parameters for each of the low delay data and the delay allowable data (step P15), and the scheduling process ends.

Note that the scheduling information notified to the baseband transmission unit 216 in step P15 may include an ACK response timing for at least one of low delay data and delay allowable data. The ACK response timing may be determined, for example, in steps P13 and P14. The ACK response timing may be determined according to, for example, the type and capability of the UE 220.

[1-4-2] Baseband Processing As illustrated in FIG. 14, when the baseband transmission unit 216 and the RF transmission unit 217 of the radio base station 210 receive the scheduling information from the scheduling unit 214, the baseband transmission unit 216 and the RF transmission unit 217, based on the scheduling information, To generate downlink transmission data.

For example, the baseband transmission unit 216 generates a reference signal for the frequency resource notified by the scheduling information. Then, the baseband transmission unit 216 performs mapping on a time-frequency resource in which the reference signal is mapped in advance (Step P21).

Also, the baseband transmission unit 216 performs coding and modulation processing on downlink control information including transmission information of both low delay data and delay allowable data using scheduling information together with the RF transmission unit 217. Then, the baseband transmission unit 216 maps the modulated downlink control information to the time frequency resource in which the downlink control information is predetermined to be mapped to the frequency resource notified by the scheduling information (step) P22).

Note that the radio base station 210 may notify the UE 220 of the ACK response timing using downlink control information, for example. When notifying the ACK response timing, the baseband transmission unit 216 may multiplex the ACK response timing information notified from the scheduling unit 214 with the downlink control information.

Further, the baseband transmission unit 216 performs encoding and modulation processing of low-delay data using scheduling information together with the RF transmission unit 217. Then, the baseband transmission unit 216 maps the modulated low delay data to the time frequency resource for low delay data transmission notified by the scheduling information (step P23).

Also, the baseband transmission unit 216 performs encoding and modulation processing of allowable delay data based on the scheduling information together with the RF transmission unit 217. Then, the baseband transmission unit 216 maps the modulated delay allowable data to the time frequency resource for delay allowable data transmission notified by the scheduling information (step P24), and the baseband processing ends.

Note that the downlink transmission data generated in steps P 21 to P 24 is subjected to the remaining transmission processing by the RF transmission unit 217 and transmitted to the UE 220 via the antenna 211.

[1-4-3] Reception Processing As illustrated in FIG. 15, the RF reception unit 222 and the baseband reception unit 223 of the UE 220 receive the reference signal from the radio base station 210 (step P31), and receive the received reference. Channel estimation is performed based on the signal (step P32).

Then, the RF receiver 222 and the baseband receiver 223 use the channel estimation result to demodulate and decode the downlink control signal (step P33), and demodulate and decode the low delay data (step P34).

The baseband receiving unit 223 determines ACK or NACK using the demodulation and decoding results of the low delay data, and notifies the baseband transmitting unit 225 of information indicating the determined ACK or NACK as feedback information (step P35). .

The RF reception unit 222 and the baseband reception unit 223 use the channel estimation result to demodulate and decode the delay tolerance data (step P36), and the reception process ends.

Note that the decoded low-delay data and delay-allowed data may be output to the layer 2 processing unit 224, respectively.

[1-4-4] Transmission Process As illustrated in FIG. 16, the UE 220 transmits an ACK / NACK response based on the ACK response timing multiplexed in the downlink control information received from the radio base station 210. Good.

For example, the layer 2 processing unit 224 and the baseband transmission unit 225 of the UE 220 generate feedback transmission data for both ACK and NACK (step P41).

Then, the baseband transmission unit 225 waits for feedback information notification from the baseband reception unit 223 (step P42). The feedback information may be notified from the baseband receiving unit 223 in step P35 of FIG. 15, for example.

The baseband transmission unit 225 determines whether or not the notified feedback information is ACK (step P43). When the feedback information is ACK (Yes in Step P43), the baseband transmission unit 225 maps the ACK feedback transmission data generated in Step P41 together with the RF transmission unit 226 and transmits it to the radio base station 210 (Step P44). ).

On the other hand, when the feedback information is NACK (No in Step P43), the baseband transmission unit 225 maps the NACK feedback transmission data generated in Step P41 together with the RF transmission unit 226, and transmits the mapped data to the radio base station 210 ( Step P45).

Thus, the transmission process by the UE 220 is completed.

Note that the ACK response timing of the transmission process illustrated in FIG. 16 may be determined for each UE 220 in advance. For example, the ACK response timing may be set for the UE 220 by the parameter setting for the UE 220 by the higher layer. Further, for example, the notification information may be set. These ACK response timings may be individually set for at least low delay data and delay tolerance data. Thus, UE220 may implement an ACK response using these preset ACK response timings.

[1-5] Modification Examples The method according to the embodiment may be modified according to any one of the following (I) to (IX) or a combination of two or more thereof.

(I) In one embodiment, the radio base station 110 transmits, to the UE 120, downlink transmission data in which low-delay data is multiplexed at a timing that precedes the delay allowable data in time. It is not limited.

As an example, after receiving low-delay data from the radio base station 110, the UE 120 may transmit UL data in order to ensure the processing time of the ACK response. That is, for the downlink radio resource for transmitting delay tolerance data, the UE 120 may transmit uplink data to the radio base station 110 instead of the downlink data being transmitted by the radio base station 110.

FIG. 17 is a diagram illustrating an example in which the UE 120 transmits UL data after receiving low-delay data. As shown in FIG. 17, the UE 120 receives a control signal instructing transmission of UL data as UL data transmission processing, performs processing such as data encoding and modulation based on the control signal, and transmits the modulated UL data. It may be transmitted to the radio base station 110. Further, as the ACK response process, the UE 120 may demodulate and decode DL data, and transmit ACK to the radio base station 110 based on the demodulation and decoding results.

As described above, the UE 120 receives the UL data transmission by the transmission system (for example, the baseband transmission unit 225 and the RF transmission unit 226 in FIG. 11), thereby receiving the reception system (for example, the RF reception unit 222 and the baseband reception in FIG. 11). The reception time of DL data in the unit 223) can be secured.

In another aspect, in order to increase the encoding processing time of the UL data by the UE 120, the radio base station 110 performs DL between the transmission of the control signal by the radio base station 110 and the transmission of the UL data by the UE 120 in the radio resource. It can also be understood as including data transmission.

Referring to FIG. 17 in detail, the radio base station 110 receives the uplink data channel and the ACK response from the UE 120 after transmitting the reference signal, the control signal, and the downlink low delay data channel as the downlink signal. It's okay. The control signal may include first information for demodulating and decoding the downlink low delay data channel in the UE 120 and second information for transmitting the uplink data channel in the UE 120. Note that the first information and the second information may each be scheduling information.

The UE 120 receives the reference signal, the control signal, and the downlink low delay data channel transmitted from the radio base station 110, demodulates and decodes the control signal using the reference signal, and is multiplexed on the control signal. You may get.

Next, the UE 120 may attempt to demodulate and decode the downlink low-delay data channel using the reference signal and the scheduling information, and determine an ACK or NACK response according to the success or failure of the decoding result. Here, when the uplink information transmission instruction is included in the scheduling information, the UE 120 encodes and modulates the uplink data so that the uplink data channel can be transmitted at a timing immediately after the downlink low delay data channel. Processing may be performed. Then, the UE 120 may transmit the modulated uplink data channel to the radio base station 110.

As described above, in the example of FIG. 17, the transmission data from the radio base station 110 to the UE 120 includes the first information used for receiving the first data and the second information used for transmitting the second data. It may be data in which the control information and the first data are multiplexed.

Also, the radio base station 110 is second data generated by the UE 120 using the second information included in the control information, and is transmitted from the UE 120 after the multiplexing timing of the first data of the transmission data. Second data may be received. Furthermore, the radio base station 110 is response information determined by the UE 120 using the first information included in the control information, and the response information transmitted from the UE 120 after the transmission timing of the second data. You may receive it.

(II) The radio base station 110 may scramble the first data by a terminal-specific sequence, for example, a UE120-specific sequence, and scramble the second data by a cell-common sequence. The second data may be descrambled by other wireless terminals in the cell, for example.

(III) The radio base station 110 may encode the first data using a terminal-specific reference signal, for example, a UE120-specific reference signal, and encode the second data using a cell-common reference signal. . The UE 120 may demodulate the first data using a terminal-specific reference signal, for example, a UE 120-specific reference signal, and demodulate the second data using a cell-common reference signal. In addition, the reference signal common to cells may be included in broadcast information such as BCH from the radio base station 110 or common information.

(IV) The error detection code such as Cyclic Redundancy Check (CRC) added to the first data and the error detection code added to the second data may have different data lengths. For example, by shortening the error detection code added to the first data than the error detection code added to the second data, the processing time for error detection and error correction for the first data can be shortened. . Thereby, time until UE120 transmits ACK response after receiving 1st data can be shortened.

(V) The radio base station 110 may apply different encoding methods to the encoding method for the first data and the encoding method for the second data.

(VI) The radio base station 110 may perform dynamic scheduling on the first data and perform semi-persistent scheduling (SPS) or persistent scheduling on the second data.

(VII) In one embodiment, the data area in the downlink transmission data addressed to the UE 120 from the radio base station 110 includes one (for example, first) or two (for example, first and second) data. However, three or more data may be included. The number n of data multiplexed in the data area (n is an integer of 1 or more) and the selection of n data are performed by, for example, the ACK / It may be determined from the time required to determine NACK and the reception time of the remaining data.

As an example, the radio base station 110 determines the data and the number of data to be multiplexed together with the first data so that the reception time is shorter and the maximum reception time than the time required for ACK / NACK determination for the first data. You can do it. In the control information described with reference to FIG. 6, individual control information may be set for each data multiplexed together with the first data.

(VIII) When the number n of data multiplexed in the data area is 2 or more, the radio base station 110 includes the start position of the second data and subsequent data in the data area, for example, included in each subframe. May be expressed by the OFDM symbol number of the data. Such a start position may be set, for example, in the control information described with reference to FIG.

(IX) The radio base station 110 may specify the transmission timing of HARQ ACK feedback for the first data and the transmission timing of HARQ ACK feedback for the second data as follows, for example.
Timing = 0 does not require HARQ ACK feedback Timing = 1 transmits HARQ ACK feedback in the same subframe Timing = 2 transmits HARQ ACK feedback in the next subframe

[2] Others The embodiments and modifications described above can be implemented with various modifications without departing from the spirit of each embodiment. Each configuration and each process of each embodiment can be selected as necessary, or may be appropriately combined.

100 Wireless communication system 110, 210, 310 Base station 120, 220, 320 Wireless terminal 130 Host device 140 Host network 211, 221, 311, 321 Antenna 212, 222 RF receiver 213, 223 Baseband receiver 214 Scheduling unit 215 Line Terminator 216, 225 Baseband transmitter 217, 226 RF transmitter 218, 229 Transmitter 219, 228 Receiver 224 Layer 2 processor 312, 322 RF circuit 313, 323 IC
314, 316, 324, 326 Storage area 315, 325 Processor 317 Network IF

Claims (17)

1. In a radio resource used for time division duplex (TDD) communication with a radio terminal, the first data is multiplexed at a timing that precedes the second data having a higher delay tolerance than the first data. A transmission unit that generates the transmitted data and transmits the transmission data to the wireless terminal;
   A receiving unit that receives, from the wireless terminal that has received the transmission data, first response information indicating successful reception or reception failure of the first data or successful decoding or decoding failure in the wireless resource; A base station.
2. The transmission data is data obtained by time-division multiplexing the first data and the second data,
   The base station according to claim 1, wherein the reception unit receives the first response information transmitted from the wireless terminal after time division multiplexing timing of the second data of the transmission data.
3. The transmission data is data obtained by spatially multiplexing the first data and the second data,
   The reception unit receives the first response information transmitted from the wireless terminal at a timing temporally preceding the spatial multiplexing timing of the second data of the transmission data. Base station.
4. The base station according to any one of claims 1 to 3, wherein the second data is broadcast information transmitted from the base station to each of a plurality of wireless terminals including the wireless terminal.
5. The base station according to any one of claims 1 to 3, wherein the second data is data transmitted in a signaling access bearer (SRB).
6. The transmission data includes first control information indicating a first transmission timing for the first response information, and a second reception success or reception failure of the second data, or a decoding success or a decoding failure. 6. The base station according to claim 1, comprising at least one of second control information indicating second transmission timing for the two response information.
7. The transmission unit includes information indicating a first transmission timing for the first response information, and second response information indicating reception success or reception failure of the second data, or decoding success or decoding failure. The base station according to any one of claims 1 to 5, wherein at least one of the information indicating the second transmission timing is notified to the wireless terminal prior to transmission of the transmission data.
8. The base station according to claim 6 or 7, wherein the information indicating the second transmission timing includes that the transmission of the second response information is unnecessary.
9. The transmitting unit scrambles the first data according to a sequence specific to the wireless terminal, and scrambles the second data according to a common sequence within a cell provided by the base station. Item 9. The base station according to any one of Items 1 to 8.
10. The transmission unit encodes the first data using a reference signal specific to the wireless terminal, and encodes the second data using a common reference signal in a cell provided by the base station. The base station according to any one of claims 1 to 9.
11. The base station according to any one of claims 1 to 10, wherein an error detection code added to the first data and an error detection code added to the second data have different data lengths. .
12. The base station according to any one of claims 1 to 11, wherein the transmission unit uses different encoding methods for the encoding method for the first data and the encoding method for the second data. Bureau.
13. The transmission unit according to any one of claims 1 to 12, wherein the transmission unit performs dynamic scheduling for the first data and performs semi-persistent scheduling or persistent scheduling for the second data. The listed base station.
14. The transmission data is data obtained by multiplexing the first data and control information including first information used for receiving the first data and second information used for transmitting the second data. Yes,
    The receiver is
    The second data generated by the wireless terminal using the second information included in the control information, from the wireless terminal after the multiplexing timing of the first data of the transmission data Receiving the transmitted second data;
    The response information determined by the wireless terminal using the first information included in the control information, the response information transmitted from the wireless terminal after the transmission timing of the second data The base station according to claim 1, wherein the base station is received.
15. In a radio resource used for time division duplex (TDD) communication with a base station, the first data is multiplexed at a timing that precedes the second data having a higher delay tolerance than the first data. A receiving unit for receiving the transmitted data from the base station;
    A wireless terminal, comprising: a transmission unit configured to transmit first response information indicating success or failure of reception of the first data, or success or failure of decoding of the first data to the base station.
16. A base station,
    A wireless terminal,
    In the radio resource used for time division duplex (TDD) communication with the radio terminal, the base station transmits the first data in terms of time more than the second data having a higher delay tolerance than the first data. To generate transmission data multiplexed at a timing preceding the transmission data, and transmit the transmission data to the wireless terminal,
    The wireless communication system, wherein the wireless terminal transmits, to the base station, first response information indicating successful reception or reception failure of the first data or successful decoding or failed decoding in the wireless resource.
17. A wireless communication method in a wireless communication system comprising a base station and a wireless terminal,
    In the radio resource used for time division duplex (TDD) communication with the radio terminal, the base station transmits the first data in terms of time more than the second data having a higher delay tolerance than the first data. To generate transmission data multiplexed at a timing preceding the transmission data, and transmit the transmission data to the wireless terminal,
    The wireless communication method, wherein the wireless terminal transmits, to the base station, first response information indicating success or failure of reception of the first data, or success or failure of decoding of the first data in the wireless resource.

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