KR101128801B1 - Method of channel status report in communication system having at least one relay station - Google Patents

Abstract

According to the present invention, in order to determine whether a base station communicates with a mobile terminal through a relay station (RS), the mobile station in the base station area receives a channel state between the RS and the terminal when the mobile terminal receives a service through the RS. It is about a method for the RS to report to the base station.

In accordance with an aspect of the present invention, a channel state reporting method includes: measuring a channel quality with a specific first terminal in a specific relay station communicating with a base station and at least one terminal; And comparing the measured channel quality with a threshold and transmitting a report message to the base station according to the comparison result, wherein the report message causes the first base station to communicate with the base station. Characterized in that the message requesting to measure the channel quality for at least one of the terminal and the particular second relay station.

Relay station, handover, channel quality, OFDM, base station, reporting

Description

Method of channel status report in communication system including relay station {Method of channel status report in communication system having at least one relay station}

1 is a diagram illustrating a network in which an RS exists.

2 is a diagram illustrating an example of a frame structure of a conventional RS.

3 is a diagram illustrating an example of a frame structure of a conventional OFDMA physical layer.

4 is a diagram illustrating an example of a communication system in which an embodiment of the present invention is implemented.

5 is a flowchart illustrating a procedure according to an embodiment of the present invention.

The present invention relates to a communication method in a communication system including a relay station, and more particularly, to determine whether a base station communicates with a mobile terminal through a relay station (hereinafter, abbreviated as 'RS'). To this end, the present invention relates to a method in which an RS reports a channel state between an RS and a terminal to a base station.

Relay stations have been proposed for the purpose of extending cell coverage and throughput in a mobile communication system. RS supports existing IEEE 802.16e terminal, has a part of BS (Base Station), and functions as an active repeater including network entry, mobility, RRM, and security of PMP-based RS. . The RS can remove noise by decoding, receiving another signal from the transmitter, encoding the signal, and transmitting the signal to the receiver. In addition, the RS serves as a digital amplifier capable of obtaining high throughput by using higher data rate coding. However, the RS has a problem of delay that may occur during decoding and encoding. In addition, the RS has a backward compatibility problem of the PMP mode.

The type of RS is classified as follows according to mobility.

Fixed RS: permanently fixed and used to increase shadow area or cell coverage. The function of a simple repeater is also possible.

2. Nomadic RS: An RS that can be temporarily installed or moved randomly within a building when a user suddenly increases.

3. Mobile RS: RS that can be mounted on public transportation such as buses and subways.

In addition, the RS may be divided into three types according to a method of using a frequency band.

Method 1: service using a new frequency band irrespective of the frequency band used by the base station

Method 2: Using a Frequency Band Used by a Base Station and Assigned by an RS to Service

Third method: A method of using the same frequency band as a base station and simply amplifying and transmitting a control signal or data received from a base station.

1 is a diagram illustrating a network in which an RS exists. The basic goal of the RS is to smooth the service by extending the service area of the base station or installing in the shadow area.

An example of the frame structure of the conventional RS is shown in FIG. A DL relay zone and an UL relay zone are set in the frame. Data transmitted by the base station to the RS is allocated to the downlink of the frame in the form of a burst, and data transmitted by the RS to the mobile terminal is allocated to the downlink region of the RS. If there is data to be transmitted by the mobile terminal to the base station, the mobile station transmits from the uplink area of the RS to the area allocated per terminal and the RS includes the data in the area allocated to the RS in the uplink.

The frame structure of the conventional OFDMA physical layer is shown in FIG.

The downlink subframe starts with a preamble used for synchronization and equalization in the physical layer, and then a downlink map in broadcast form that defines the location and use of bursts allocated to the downlink and uplink. The structure of the entire frame is defined through a DL-MAP message and an UL-MAP message.

Tables 1 and 2 below show examples of DL-MAP messages and UL-MAP messages, respectively.

The DL-MAP message defines the use allocated per burst for the downlink period in the burst mode physical layer, and the UL-MAP message defines the use of the burst allocated for the uplink period. Information element (IE) constituting DL-MAP is based on Downlink Interval Usage Code (DIUC), Connection ID (CID), and location information (subchannel offset, symbol offset, subchannel number, symbol number) of burst. Downlink traffic intervals are divided at the user end. On the other hand, the information element constituting the UL-MAP message is determined by the Uplink Interval Usage Code (UIUC) for each CID (Connection ID), the location of the interval is defined by the duration. Here, the purpose of each section is determined according to the UIUC value used in the UL-MAP, and each section starts at a point separated by the duration defined in the UL-MAP IE from the previous IE start point.

Hereinafter, UL-MAP will be described.

The UL-MAP allocates usage rights for an uplink channel. The usage of uplink bursts is defined using successive information elements defining usage of each uplink interval, and the usage of uplink resources allocated as a unit of an OFDMA symbol and a subchannel block is defined.

Hereinafter, an information element for UL MAP (UL-MAP IE) will be described. The information element (UL-MAP IE) for the UL MAP specifies band allocation information for uplink. Each UL-MAP message includes at least one IE to indicate the end of the last burst. The order of the IEs sent by the UL-MAP is determined by the physical layer used. CID assigns IE to unicast, multicast, and broadcast addresses. If the bandwidth grant is explicitly specified to be allocated, the basic CID of the terminal is used as the CID value. UIUC is used to specify an uplink usage type and an associated uplink burst profile. For each UIUC to be used in UL-MAP, Uplink_Burst_Profile must be included in UCD. IEs must all be supported by terminals. The base station may use any of these information elements when generating the UL-MAP message.

Syntax Size Notes DL-MAP_IE () { DIUC 4 bits if (DIUC == 15) { Extended DIUC dependent IE variable See clauses following 8.4.5.3.1 } else { if (INC_CID == 1) { The DL-MAP starts with INC_CID = 0. INC_CID is toggled between 0 and 1 by the CID-SWITCH_IE () (8.4.5.3.7) N_CID 8 bits Number of CIDs assigned for this IE for (n = 0; n <N_CID; n ++) { CID 16 bits } } OFDMA  Symbol offset 8 bits Subchannel  offset 6 bits Boosting 3 bits 000: normal (not boosted); 001:
+6 dB; 010: -6 dB; 011: +9 dB; 100:
+3 dB; 101: -3 dB; 110: -9 dB; 111:-
12 dB; No. OFDMA  Symbols 7 bits No. Subchannels 6 bits Repetition Coding Indication 2 bits 0b00-No repetition coding of 0b01-Repetition coding of 2 used 0b10-Repetition coding of 4 used 0b11-Repetition coding of 6 used } }

Syntax Size Notes UL-MAP_Message_Format () { Management Message Type = 3 8 bits reserved 8 bits Shall be set to zero. UCD Count 8 bits Allocation Start Time 32 bits Begin PHY Specific Section { See applicable PHY section. if (WirelessMAN-OFDMA) { No. OFDMA symbols 8 bits Number of OFDMA symbols in the UL subframe } for ( i = 1; i <= n ; i ++) { For each UL-MAP element 1 to n . UL-MAP_IE () variable See corresponding PHY specification. } } if! (byte boundary) { Padding nibble 4 bits Padding to reach byte boundary. } }

Syntax Size  (bits) Notes UL-MAP_IE () { CID 16 UIUC 4 if (UIUC == 11) { Extended UIUC 2 dependent IE variable See subclause 8.4.5.4.4.2 } elseif (UIUC == 12) { OFDMA symbol offset 8 Subchannel offset 7 No. OFDMA symbols 7 No. subchannels 7 Ranging method 2 0b00-Initial Ranging / Handover Ranging over two symbols
0b01-Initial Ranging / Handover Ranging over four symbols
0b10-BW Request / Periodic Ranging over one symbol
0b11- BW Request / Periodic Ranging over three symbols Dedicated ranging indicator One 0: the OFDMA region and Ranging Method defined are used for the purpose of normal ranging
1: the OFDMA region and Ranging Method defined are used for the purpose of ranging using dedicated CDMA code and transmission opportunities assigned in the MOB_PAG-ADV message or in the MOB_SCN-RSP message. } else if (UIUC == 13) { PAPR_Reduction_and_Safety_Zo ne_Allocation_IE 32 } else if (UIUC == 14) { CDMA_Allocation_IE () 32 } else if (UIUC == 15) { Extended UIUC dependent IE variable See subclauses following 8.4.5.4.3 } else if (UIUC == 0) { FAST-FEEDBACK_Allocation_IE () 32 } else { Duration 10 In OFDMA slots (see 8.4.3.1) Repetition coding indication 2 0b00 -No repetition coding
0b01 -Repetition coding of 2 used
0b10 -Repetition coding of 4 used
0b11 -Repetition coding of 6 used if (AAS or AMC UL Zone) { AAS / AMC Allocations include absolute slot off-set. Slot offset 12 Offset from start of the AAS or AMC zone for this allocation, specified in slots. } } }

In a conventional mobile communication system, operations of a CQICH channel and a REP-REQ / RSP MAC message, which is a method of requesting downlink signal quality information for a mobile station by a base station, are as follows.

(1) CQICH channel

As a method for acquiring downlink signal quality information of a mobile station by a base station, there is a method of pre-allocating some zones to a CQICH dedicated channel in a two-dimensional map of uplink and then designating a subchannel to be used for each terminal.

As shown in FIG. 3, the CQICH channel zone is pre-allocated using the FAST-FEEDBACK channel in the UL-MAP IE in the UL-MAP, and then slots are designated for each UE by using CQICH_Alloc_IE or CQICH_Enhance_Allocation_IE. For example, MS # 1 can specify CQICH # 1, MS # 2 can specify CQICH # 2, CQICH # 3, and MS # 3 can specify CQICH # 4.

CQICH_Alloc_IE dynamically allocates CQICH to the uplink of the UE or cancels the allocated area. Once allocated, the UE transmits signal quality information to the allocated CQICH region at a period set in CQICH_Alloc_IE. If the terminal cancels the allocated CQICH, that is, duration = 0 is set in the CQICH_Alloc_IE, the terminal does not transmit signal quality information to the base station.

Syntax Size Notes CQICH_Alloc_IE () () { Extended UIUC 4 bits CQICH = 0x03 Length 4 bits Length of the message in bytes (variable). CQICH _ID variable Index to uniquely identify the CQICH resource assigned to the SS. The size of this field is dependent on system parameter defined in UCD. Allocation offset 6 bits Index to the fast feedback channel region marked by UIUC = 0. Period (p) 2 bits A CQI feedback is transmitted on the CQICH every 2 ^p frames. Frame offset 3 bits The SS starts reporting at the frame of which the number has the same 3 LSB as the specified frame offset. If the current frame is specified, the SS should start reporting in eight frames Duration (d) 3 bits A CQI feedback is transmitted on the CQI channels indexed by the CQICH_ID for 10 x 2dframes.
If d == 0, the CQICH is deallocated.
If d == 0b111, the SS should report until the BS command for the SS to stop. Report configuration included 1 bits Update to CINR report configuration is included. If (report configuration included == 1) { Feedback Type 2 bits 0b00 = physical CINR feedback
0b01 = effective CINR feedback
0b10-0b11 = Reserved Report type 1 bit 0: Report for preamble
1: Report for specific permutation zone If (Report type == 0) { CINR  preamble report type 1 bit The type of preamble-based CINR report
0-Frequency reuse factor = 1 configuration.
1-Frequency reuse factor = 3 configuration. } Else { report for permutation zone. Zone permutation 3 bits The type of zone for which to report 0b000-PUSC with 'use all SC = 0'
0b001-PUSC with 'use all SC = 1'
0b010-FUSC
0b011-Optional FUSC 0b100-Safety Channel region 0b101-AMC zone (only applicable to AAS mode) 0b110-111-Reserved Zone type 2 bits 0b00-non-STC zone 0b01-STC zone
0b10-AAS zone
0b11-reserved Zone PRBS _ID 2 bits The PRBS_ID of the zone on which to report If (Zone type == 0b000 or 0b001) { Major group indication 1 bit If '0' then the report may refer to any subchannel in the PUSC zone. If (Major group indication == 1) { PUSC  Major group bitmap 6 bits Reported CINR shall only apply to the subchannels of PUSC major groups for which the corresponding bit is set. Bit # k refers to major group k . } } CINR  zone measurement type 1 bit 0: measurement from pilot subcarriers and, if AAS zone, from AAS preamble.
1: measurement from data subcarriers } If (feedback type == 0b00) { Physical CINR feedback Averaging parameter included 1 bit If (Averaging parameter included == 1) { Averaging parameter 4 bits Averaging parameter used for deriving physical CINR estimates reported through CQICH. This value is given in multiples of 1/16 in the range of [1 / 16..16 / 16] in increasing order. a _avg } } } MIMO _permutation_feedback_cycle 2 bits 0b00 = No MIMO and permutation mode feedback
0b01 = The MIMO and permutation mode indication shall be transmitted on the CQICH indexed by the CQICH_ID every four allocated CQICH transmission opportunity. The first indication is sent on the fourth allocated CQICH frame transmission opportunity.
0b10 = The MIMO mode and permutation mode indication shall be transmitted on the CQICH indexed by the CQICH_ID every eight allocated CQICH transmission opportunity. The first indication is sent on the eighth allocated CQICH trans-mission opportunity.
0b11 = The MIMO mode and permutation mode indication shall be transmitted on the CQICH indexed by the CQICH_ID every 16 allocated CQICH transmission opportunity. The first indication is sent on the 16th allocated CQICH transmission opportunity. Padding variable Number of bits required to align to byte length, shall be set to zero. }

(2) REP-REQ / RSP MAC messages

A. Channel measurement report request (REP-REQ)

This message is used when a base station operating in a band below 11 GHz requests a downlink channel measurement result such as RSSI and CINR of a terminal.

Syntax Size Notes Report_Request_Message_Format () { Management Message Type = 36 8 bits Report Request TLVs variable }

The REP-REQ message has the following TLV encoded parameters as follows.

Name Type Length Value Report request One variable Compound

The signal quality information Report Response message should be used for the response of the Report Request channel measurement list received by the terminal.

Name Type Length Value Report type 1.1 One Bit # 0 = 1 Include DFS Basic report
Bit # 1 = 1 Include CINR report
Bit # 2 = 1 Include RSSI report
Bit # 3-6 a _avg \ in multiples of 1/32 (range [1/32, 16/32])
Bit # 7 = 1 Include current transmit power report Channel number 1.2 One Physical channel number (see 8.5.1) to be reported on. (license-exempt bands only) Channel Type request 1.3 One 0b00 = Normal subchannel,
0b01 = Band AMC Channel,
0b10 = Safety Channel,
0b11 = Sounding Zone-specific
physical CINR
request 1.4 3 Bits # 0-2: Type of zone on which CINR is to be reported
0b000: PUSC zone with 'use all SC = 0'
0b001: PUSC zone with 'use all SC = 1' / PUSC AAS zone
0b010: FUSC zone
0b011: Optional FUSC zone
0b100: Safety Channel region
0b101: AMC zone (only applicable to AAS mode)
0b110-0b111: Reserved
Bit # 3: 1 if zone for which CINR should be estimated is STC zone, 0 otherwise.
Bit # 4: 1 if zone for which CINR should be estimated is AAS zone, 0 otherwise.
Bits # 5-6: PRBS_ID of the zone for which CINR should be estimated. Ignored for Safety Channel.
Bit # 7: Data / pilot-based CINR measurement:
0-Report the CINR estimate from pilot subcarriers,
1-Report the CINR estimate from data subcarriers
Bits # 8-13: Reported CINR shall only be estimated for the subchannels of PUSC major groups for which the corresponding bit is set. Bit # ( k +7) refers to major group k. Only applicable for CINR measurement on a PUSC zone
Bits # 14-17: a _avg in multiples of 1/16 (range is [1 / 16,16 / 16])
Bit # 18: 0-report only mean of CINR
1-report both mean and standard deviation of CINR
Bits # 19-23: Reserved, shall be set to zero Preamble physical CINR request 1.5 One Bits # 0-1: Type of preamble physical CINR measurement
0b00-Report the estimation of CINR measured from preamble for frequency reuse configuration = 1
0b01-Report the estimation of CINR measured from preamble for frequency reuse configuration = 3
0b10-Report the estimation of CINR measured from preamble for band AMC
0b11- Reserved
Bits # 2-5: in multiples of 1/16 (range is [1 / 16,16 / 16]) Bit # 6: 0-report only mean of CINR 1-report both mean and standard deviation of CINR
Bit # 7: Reserved , shall be set to zero a _avg Zone-specific effective CINR request 1.6 2 Bits # 0-2: Type of zone on which effective CINR is to be reported
0b000: PUSC zone with 'use all SC = 0'
0b001: PUSC zone with 'use all SC = 1' / PUSC AAS zone
0b010: FUSC zone
0b011: Optional FUSC zone
0b100: Reserved
0b101: AMC zone (only applicable to AAS mode)
0b110-0b111: Reserved
Bit # 3: 1 if zone for which effective CINR should be reported is STC zone, 0 otherwise.
Bit # 4: 1 if zone for which effective CINR should be estimated is AAS zone, 0 otherwise.
Bits # 5-6: PRBS_ID of the zone for which effective CINR should be reported. Ignored for Safety Channel. Bit # 7: Data / pilot-based effective CINR measurement: 0-Report the CINR estimate from pilot subcarriers,
1-Report the CINR estimate from data subcarriers
Bits # 8-13: Reported effective CINR shall only be estimated for the subchannels of PUSC major groups for which the corresponding bit is set. Bit # ( k +7) refers to major group k . Only applicable for CINR measurement on a PUSC zone
Bit # 14-15: Reserved , shall be set to zero Preamble effective CINR request 1.7 One Bits # 0-1: Type of preamble-based effective CINR measurement
0b00-Report the estimation of effective CINR measured from preamble for frequency reuse configuration = 1
0b01-Report the estimation of effective CINR measured from preamble for frequency reuse configuration = 3
0b10-11- Reserved
Bit # 2-7: Reserved , shall be set to zero Channel selectivity report 1.8 One Bit # 0: 1-include frequency selectivity report
Bit # 1-7: Reserved , shall be set to zero

B. Channel measurement Report Response (REP-RSP)

It is used by the mobile terminal to respond to the listed channel measurements in the received report request. The terminal transmits the measurement results for the channels listed in the received channel measurement report request message in the channel measurement report response message. The type of channel quality reported depends on the type of channel currently being used for communication with the base station. Table 6a below shows the format of the channel measurement result response message.

Syntax Size Notes Report_Response_Message_Format { Management Message Type  = 37 8 bits Report Response TLVs variable }

Name Type Length Value Report One variable Compound Channel Type Report in WirelessMAN OFDMA PHY 2 variable Compound Current transmitted power 147 One See 8.3.7.4 and 11.1.1

The report on the content reported through the channel measurement result response message and the channel type is composed of the parameters shown in Table 6b below.

REP - REQ  Report type Name Type Length Value bit # 0 = 1 Channel number 1.1 One Physical channel number (see 8.5.1) to be reported on bit # 0 = 1 Start frame 1.2 2 16 LSBs of Frame number in which measurement for this channel started bit # 0 = 1 Duration 1.3 3 Cumulative measurement duration on the channel in multiples of Ts. For any value exceeding 0xFFFFFF, report 0xFFFFFF bit # 0 = 1 Basic report 1.4 One Bit # 0: WirelessHUMAN detected on the channel
Bit # 1: Unknown transmissions detected on the channel
Bit # 2: Specific Spectrum User detected on the channel
Bit # 3: Unmeasured. Channel not measured bit # 1 = 1 CINR report 1.5 2 1 byte: mean (see also 8.2.2, 8.3.9, 8.4.11) for details) 1 byte: standard deviation bit # 2 = 1 RSSI report 1.6 2 1 byte: mean (see also 8.2.2, 8.3.9, 8.4.11) for details) 1 byte: standard deviation

REP - REQ Channel  Type request  ( binary ) Name Type Length Value 01 Band AMC Report
(CQI value)
2.2 5 First 12 bits for the band indicating bitmap and next 20 bits for CINR measurement (5 bits per each band) 11 Sounding report 2.5 One Average SINR.
8 bits in the same format used in
8.4.11.3

Existing communication systems provide a method for providing a handover by receiving a signal quality information of a downlink / uplink channel directly between a base station and a mobile terminal from the terminal. However, the related art does not provide a method for communication between the terminal, the RS, and the base stations with respect to a communication system including the RS according to a change in channel environment.

The present invention has been proposed to improve the above-described prior art, and an object of the present invention is to provide a method for controlling transmission and reception of data between the RS and a terminal and a base station according to a change in a communication environment in a communication system including an RS. will be.

Summary of the invention

The present invention relates to a terminal for communicating with a base station via RS. The present invention provides a method for reporting an RS to a base station when uplink / downlink signal quality information between the RS and the UE is worsened. The present invention defines a mechanism for the RS to report the channel state between the RS and the terminal to the base station when the terminal in the base station area receives the service through the RS. In addition, the present invention provides a method for relaying a service that was relayed through a specific first RS through a specific second RS.

In accordance with an aspect of the present invention, a channel state reporting method includes: measuring a channel quality with a specific first terminal in a specific relay station communicating with a base station and at least one terminal; And comparing the measured channel quality with a threshold and transmitting a report message to the base station according to the comparison result, wherein the report message causes the first base station to communicate with the base station. Characterized in that the message requesting to measure the channel quality for at least one of the terminal and the particular second relay station.

In addition, the channel status reporting method according to the present invention, in a base station communicating with at least one of one or more terminals and one or more relay stations, the channel quality from a specific first relay station for relaying a specific first terminal Receiving a report message requesting a measurement; And measuring the channel quality of at least one of the first terminal and the specific second relay station according to the report message.

In addition, the channel state reporting method according to the present invention, the terminal for communicating with a communication system including at least one relay station (Relay Station) and at least one base station, comprising the steps of: transmitting data to a specific first relay station; And receiving data transmitted through a data path selected according to the channel quality measured by the transmission data, wherein the data path is configured to determine the measured channel quality by a specific second relay station and the base station. It is determined by the result of comparison with any one of the channel quality between the terminal and the.

One embodiment of the present invention

Specific features, operations, and effects of the present invention will be embodied by one embodiment of the present invention described below.

One embodiment of the present invention relates to a terminal communicating with a base station via RS. The base station is a node connected to a backbone network and performs communication with the RS and the terminal. The RS is a node that communicates with the base station, and the RS transmits and receives data wirelessly with the base station. In addition, the RS is more preferably in communication with the base station in the OFDM / OFDMA scheme. The RS may perform a relay between the base station and the terminal. The relay refers to a series of communication procedures for receiving data to be transmitted to the terminal from the base station and transmitting the data to the terminal, and receiving data to be transmitted to the base station from the terminal. As described above, the relay is preferably performed in the OFDM / OFDMA scheme. The relay is preferably performed by various communication methods, and receives and decodes data encoded in any first scheme from the terminal, and encodes the decoded data in the first scheme or any second scheme. It may be a method for transmitting to the base station. In addition, it may be a method of transmitting and receiving by amplifying the magnitude of the transmitted and received data signal for the terminal. The method may be a method of attaching specific additional data to data received from the terminal and transmitting the specific additional data to the base station, or modifying data received from the terminal and transmitting the modified data to the base station. The RS is connected to the base station, and the number of RSs is not limited. The terminal is a node connected to the base station or the RS, and the type of the terminal may be a mobile terminal having mobility or a fixed terminal fixed at a specific location.

According to an embodiment of the present invention, when a specific event occurs, the RS requests the base station to measure channel quality. That is, according to an embodiment of the present invention, when a terminal in the base station area receives a service through the RS, the RS reports a channel state to the base station, but reports a channel state between the RS and the terminal. It characterized in that to provide. In addition, the present embodiment provides a method of relaying a service that was relayed through a specific first RS through a specific second RS.

As described above, the RS requests the base station to measure channel quality. The channel quality is requested from an RS (hereinafter, referred to as a 'first RS') that performs a relay for a current UE, and between the base station and an RS other than the first RS (hereinafter, referred to as a 'second RS'). It may be channel quality or channel quality between the base station and the terminal. The channel quality indicates a state of a channel between specific nodes. For example, the channel quality may mean a quality of a signal transmitted through an uplink or a quality of a signal transmitted through a downlink. The channel quality can be measured by various methods. For example, a specific channel for measuring channel quality may be set, and the quality of the channel may be measured by observing the specific channel. In addition, a message indicating the measurement of the quality of the downlink may be transmitted to the terminal, and the message received from the terminal may be demodulated to measure the quality of the downlink. In this case, the quality of the uplink may be measured using a message for reporting the downlink quality.

As described above, the first RS according to the present embodiment requests the base station to measure channel quality when a specific event occurs. For the request, the first RS requests a specific terminal having a poor connection. It may transmit information about the channel status between the first RS and the specific terminal, or may transmit a message requesting the base station to measure the channel quality. The base station receiving the message requesting to measure the channel quality may measure the channel quality between the first RS and the base station or measure the channel quality between the terminal and the base station. For example, when an event occurs because the uplink signal quality information between the first RS and an arbitrary terminal falls below a reference value, the first RS transmits the uplink signal quality information to the base station to the base station. Report. The base station reported from the first RS requests uplink signal quality information between a neighbor RS (eg, a second RS) of the first RS and the terminal, or a direct downlink / uplink link between the base station and the terminal. Signal quality information can be requested.

When a specific event occurs, the first RS according to the present embodiment may provide the base station with information about the specific second RS for relaying the terminal. That is, when an event such as a decrease in channel quality between the first RS and the terminal occurs, the first RS may propose a candidate RS capable of relaying the terminal. Through this operation, the first RS may assist the base station in measuring channel quality. In order for the first RS to propose the candidate RS, the first RS needs to know information about RSs located around the first RS, so that information about an RS located around the first RS is provided. It is preferably provided from the base station to the first RS. Preferably, the information about the RS located around the first RS is broadcast, and the information about the broadcast RS is repeated periodically or aperiodically, and the information about the RS is transmitted to at least one RS. It is more preferable that the information is related. In addition, the base station receiving the candidate RS may first measure channel quality with respect to the candidate RS. The first RS according to the present embodiment may first request that the base station measure channel quality with the terminal. If the first RS requests the base station to measure the channel quality between the terminal and the base station, the base station measures the channel quality between the terminal and the terminal, and if the first RS to the base station When requesting to measure the channel quality between the second RS and the terminal, the base station may measure the channel quality between the second RS and the terminal.

The base station according to the present embodiment measures the channel quality according to the request of the first RS, and causes the second RS to perform a relay for the terminal by using the results of measuring the channel quality, 1 It is desirable to determine whether to continue to perform the relay or to communicate directly with the terminal. For example, the base station compares the uplink signal quality information between the second RS and the terminal with the uplink signal quality information between the first RS and the terminal and has a higher quality than the reference value. RS can be selected. In addition, the base station measures the channel quality between the terminal and the base station to measure the quality above a certain threshold value, or when the quality is excellent compared to the channel quality between the RS and the terminal, the RS without passing through the Communication with the terminal can be performed directly. The base station may use a conventional CQICH channel and a REP-REQ / RSP MAC management message as a method of determining whether to communicate directly with the terminal.

The information about the channel quality between the RS and the terminal can be obtained by the RS at the request of the base station, and the RS is obtained in advance before the request of the base station and immediately sent to the base station when the base station requests. Can provide.

As described above, the present embodiment is performed when a specific event occurs. When the channel quality between the first RS and the terminal falls below a predetermined threshold, the event may occur. The event may be repeated by a predetermined period or may be repeated aperiodically. In addition, the event may occur due to a control message of a Beckon network controlling the base station.

Hereinafter, examples of a case where the first RS requests channel quality to the base station when the terminal exists within the coverage of the base station.

(1) An example of a case where the base station and the terminal communicate directly with the mobile terminal while communicating through the RS:

When the terminal receives a service from the base station through the first RS and moves out of the coverage of the first RS to the area of the base station, uplink signal quality information between the first RS and the terminal becomes worse. . The first RS requests the base station to obtain direct uplink signal quality information between the base station and the terminal, and after the base station receives uplink signal quality information from the terminal, direct communication with the terminal is further performed. In good cases it communicates directly with the terminal, not via the RS.

(2) An example of a procedure in which a base station and a terminal relay through an RS and perform a handover to an adjacent RS:

When the terminal receives a service from the base station through the first RS and then moves out of the area of the first RS to an adjacent second RS area, uplink signal quality information between the first RS and the terminal becomes worse. In this case, the first RS requests the base station to obtain uplink signal quality information between the second RS and the terminal, and the base station receives the uplink signal quality information between the second RS and the terminal. It is possible to select a better quality RS from the first RS and the second RS to perform the relay.

In the present embodiment, when the uplink signal quality information between the first RS and the terminal becomes less than the reference value, the RS proposes a procedure for reporting the terminal to the base station, whereby the base station selects an appropriate RS or Determine direct communication, improve throughput, and enable continuous service.

4 is an example of a communication system in which an embodiment of the present invention is implemented. 5 is a process flow diagram according to an embodiment of the present invention. Hereinafter, an operation according to an embodiment of the present invention will be described with reference to FIGS. 4 and 5. The embodiment of FIG. 5 proposes a method of using the RS-REPORT MAC management message according to the present embodiment as a method for the first RS to report to the base station.

The communication system of FIG. 4 includes one base station and two RSs (first RS, second RS) and at least one terminal (first terminal) in communication with the RS or base station. When the base station communicates with the first terminal, as the first terminal receives the service of the base station through the first RS and moves to the area of the second RS, a channel state between the first terminal and the first RS May worsen below the reference value. In this case, the first RS reports to the base station. The performing of the report may include transmitting a REP-REQ MAC message to the base station by the first RS. The base station may receive the REP-REQ MAC message and obtain a channel state between the first terminal and the base station and a channel state between the second RS and the terminal.

Hereinafter, the procedure flowchart of FIG. 5 will be described. The example of FIG. 5 may be applied when the first terminal enters the region of the second RS from the region of the first RS.

Hereinafter, a base station communicating with the terminal is called a serving base station. The serving base station communicates with the terminal using the first RS (S501 to S504). That is, the first RS may relay data for the first terminal. In detail, the serving base station transmits data to the first RS (S501), and the first RS transmits data to the first terminal (S502). As a result, the first terminal receives a service from the serving base station. The first terminal transmits data to the first RS (S503), and the first RS transmits data to the serving base station (S504).

When data is relayed through the first RS as described above, the first RS may measure channel quality between the first terminal and the first RS. The channel quality may be repeatedly measured periodically or aperiodically, and may also be measured by a control signal by an external node such as a base station or a backbone network. When the channel quality is measured, the RS checks whether the measured channel quality decreases below a specific reference value (S505). The embodiment of FIG. 5 checks the quality of the uplink channel as an example of channel quality.

If the result of the check that the channel quality is less than the reference value, the first RS transmits a report message to the serving base station (S506). 5, an RS-REPORT MAC management message is used as the report message. The report message may include various information. The embodiment of FIG. 5 includes information on channel quality between the first RS and the first terminal.

If uplink signal quality information of the first terminal received by the first RS, that is, uplink signal quality information between the first RS and the first terminal is less than or equal to a reference value, the first RS excludes the first RS. Uplink signal quality information between an RS (eg, a second RS) adjacent to the first terminal in the serving base station and the first terminal may be obtained. In addition, the serving base station may obtain information about channel quality between the first terminal and the serving base station.

The serving base station allocates uplink to the first terminal whose uplink signal quality information reported from the first RS is equal to or less than a reference value (S507).

The serving base station requests a message (REP-RSDetect-REQ) for instructing the first RS to monitor uplink for the first terminal to the second RS (S508).

When there is data to be transmitted to the serving base station by the first terminal allocated the uplink from the serving base station through step S507, the data is transmitted through the allocated uplink (S509). When the first terminal transmits data to the serving base station, the second RS confirms uplink signal quality information of the data received from the first terminal (S510). The second RS includes the uplink signal quality information in the REP-RSDetect-RSP message, which is a response to the message (REP-RSDetect-REQ) instructing to monitor the uplink, and transmits the uplink signal quality information to the serving base station (S511). .

If there is no data to be transmitted to the serving base station by the first terminal allocated the uplink from the serving base station in step S507, the first terminal performs a periodic ranging (ranging). When the mobile terminal performs periodic ranging, the first terminal requests an RNG-REQ message to the serving base station (S512). When the second RS receives the RNG-REQ message from the first terminal, the second RS may check uplink signal quality information (S513). The uplink signal quality information of the first terminal received by the second RS is transmitted from the second RS to the serving base station in the form of the REP-RSDetect-RSP message (S514).

The serving base station may request channel state information directly from the first terminal without passing through the RS. In this case, the serving base station transmits a conventional REP-REQ message to the first terminal to request signal quality information for downlink of the first terminal. When the first terminal receives the REP-RSP message to the serving base station (S515), it transmits downlink signal quality information between the serving base station and the first terminal through the REP-RSP (S516). In addition, in step S516, the serving base station may acquire signal quality information on downlink / uplink between the serving base station existing in the cell region and the first terminal.

The serving base station receiving the REP-RSDetect-RSP message from at least one RS (RSs other than the first RS) includes uplink signal quality information and the first information when receiving the REP-RSDetect-RSP message. 1 RS compares uplink signal quality information of the first UE transmitted (S517). As a result of the comparison, a specific RS indicating that uplink signal quality information is equal to or greater than a reference value and exhibits excellent quality is selected, or a method of directly communicating with the first terminal is selected. For example, when the channel quality between the second RS and the first terminal is higher than the reference value and indicates the best quality, the second RS may perform a relay. In this case, the second RS performs a relay (S518 to S519).

Table 7 below shows an example of an RS-REPORT MAC management message used in the embodiment of FIG. 5.

Syntax Size Notes RSREP-REQ () { Management message type 8 bits Number of MS 7 bits Numbers of MSs. For (i = 0; i <Number of MS; i ++) { CID 16 bits MS CID may be detected by RS in the current frame. Report type 1 bit 0: report for CINR
1: report for RSSI If (report type == 0) { Channel quality } Else if (report type == 1) { Channel quality } } } }

The message of Table 7 may be transmitted from the first RS to transmit CINR or RSSI information to the serving base station. The CINR and RSSI merely indicate an example of a parameter for indicating channel quality, and the message may include other types of parameters. The message of Table 7 is an example of reporting information about the first terminal and channel quality between the first terminal and the first RS, but other information may be included in the RS-REPORT MAC management. As described above, the first RS may also transmit information about the second RS to the serving base station to assist in checking the channel quality of the serving base station. Information about located RSs may be included. In addition, according to the above description, the serving base station may first check channel quality with the first terminal in the first RS, and information regarding priority for checking channel quality in the message of Table 7 is also provided. Can be included. For example, priority may be assigned to check channel quality for direct communication between the terminal and the serving base station first, and then check channel quality for relay by the RS later.

Those skilled in the art through the above description can be seen that various changes and modifications can be made without departing from the spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

The present invention proposes a method for the base station to report uplink signal quality information between the mobile station and the relay station (RS) to the base station, and if the RS exists between the existing base station and the mobile station, whether the relay is performed through the RS. Allow the base station to determine efficiently. Therefore, a seamless base station can be provided, and the service area of the base station can be expanded and smoothed even in a shadowed area. In addition, since the base station can manage the group of mobile terminals receiving the service of the RS, it is possible to reduce the resource distribution of the service base station and the power consumption of the mobile terminal.

Claims (15)

In the method for measuring the signal quality in a communication system including at least one relay station (RS), Receiving, by a base station, a first report message including first signal quality information between the first relay station and a terminal from a first relay station; Transmitting, by the base station, a request message for requesting measurement of signal quality between the second relay station and the terminal to a second relay station; Receiving a second report message for reporting second signal quality information between the second relay station and the terminal from the second relay station; And Comparing the first signal quality information with the second signal quality information, and transmitting data to the terminal through the first relay station or the second relay station having better quality, The first report message is transmitted from the first relay station without the request of the base station, The second report message is transmitted from the second relay station in response to the request message. The method of claim 1, And the first report message is transmitted when the first channel quality information satisfies a predetermined event occurrence condition. The method of claim 1, And the first report message is transmitted at predetermined intervals. The method of claim 1, And the base station selects an optimal communication route by comparing the first signal quality information and the second signal quality information. The method of claim 1,  Wherein the first signal quality information and the second signal quality information are each represented by one of a carrier to interface noise ratio (CINR) or a receive signal strength indicator (RSSI). A base station for measuring signal quality in a communication system including one or more relay stations, the base station comprising: Receiving a first report message including first signal quality information between the first relay station and a terminal from a first relay station; Transmitting a request message requesting measurement of signal quality between the second relay station and the terminal to a second relay station; Receiving a second report message for reporting second signal quality information between the second relay station and the terminal from the second relay station; And Comparing the first signal quality information and the second signal quality information, and performing the step of transmitting data to the terminal through the first relay station or the second relay station having a better quality, The first report message is transmitted from the first relay station without the request of the base station, The second report message is transmitted from the second relay station in response to the request message. The method of claim 6, And the first report message is transmitted when the first channel quality information satisfies a predetermined event occurrence condition. The method of claim 6, And the first report message is transmitted every predetermined period. The method of claim 6, The base station further comprises the step of comparing the first signal quality information and the second signal quality information to select an optimal communication route. The method of claim 6,  And the first signal quality information and the second signal quality information are each represented by one of a carrier to interface noise ratio (CINR) or a receive signal strength indicator (RSSI). delete delete delete delete delete

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