KR100703131B1 - Method and apparatus for scheduling assignment of uplink packet transmission in mobile telecommunication system - Google Patents

Abstract

According to the present invention, in a mobile communication system supporting an enhanced uplink packet data service, a buffer state of a buffer storing packet data to be transmitted by a user terminal for scheduling of the uplink packet data service and an uplink transmission power of the uplink packet data are determined. A method of transmitting a channel state, the method comprising: acquiring different buffer state transmission periods and channel state information transmission periods, and when the amount of packet data stored in the buffer is greater than or equal to a predetermined threshold, Starting the transmission of the state and the channel state, and after transmitting the buffer state and the channel state, periodically transmitting the buffer state and the channel state according to the buffer state transmission period and the channel state transmission period. Characterized in that the process is made.

EUDCH, Buffer Status, CSI, Transmission Format Determination, Scheduling Allocation

Description

TECHNICAL AND METHOD AND APPARATUS FOR SCHEDULE FOR UPLINK PACKET TRANSMISSION IN MOBILE COMMUNICATION SYSTEM {METHOD AND APPARATUS FOR SCHEDULING ASSIGNMENT OF UPLINK PACKET TRANSMISSION IN MOBILE TELECOMMUNICATION SYSTEM}

1A is a diagram illustrating a change in uplink radio resources of a base station when base station control scheduling is not used.

1B is a diagram illustrating a change in uplink radio resources of a base station when using base station control scheduling.

2 is a diagram illustrating a user terminal and a base station for performing uplink packet transmission.

3 is a diagram illustrating information transmitted and received between a user terminal and a base station to perform uplink packet transmission.

4 is a diagram illustrating a transmitter structure of a user terminal for transmitting an uplink packet.

5A and 5B illustrate a structure of a scheduling control channel of a base station for receiving an uplink packet and a structure of a scheduling transmitter.

6 is a diagram illustrating continuous transmission of a buffer state and a channel state for Node B control scheduling.

7 is a diagram illustrating an uplink power control operation of a user terminal located in a soft handover region.

8 is a flowchart illustrating a setting operation of a channel state transmission period according to an embodiment of the present invention.

9 is a diagram showing a transmission state of a buffer state and a channel state according to a preferred embodiment of the present invention.

10 illustrates transmission of a buffer state and a channel state according to an embodiment of the present invention.

11 illustrates transmission of a buffer state and a channel state according to another embodiment of the present invention.

12 is a diagram illustrating an EUDCH transmission controller structure of a user terminal for transmitting a buffer state and a channel state according to an embodiment of the present invention.

13 is a flowchart illustrating an operation of a user terminal for transmitting a buffer state and a channel state according to a preferred embodiment of the present invention.

FIG. 14 is a diagram illustrating an EUDCH receiver structure of a base station for receiving a buffer state and a channel state according to an embodiment of the present invention. FIG.

15 is a flowchart illustrating the operation of a base station receiving a buffer state and a channel state according to a preferred embodiment of the present invention.

16 illustrates the structure of an EU-SCHCCH receiver of a user terminal for receiving scheduling assignment information according to an embodiment of the present invention.

17 is a flowchart illustrating a receiving operation of a user terminal receiving scheduling assignment information according to an exemplary embodiment of the present invention.

The present invention relates to a mobile communication system, and more particularly, to a method and apparatus for efficiently transmitting and receiving scheduling allocation information for transmitting packet data through an uplink.

Wideband Code Division Multiple Access (WCDMA), which is asynchronous, is an enhanced uplink dedicated channel (hereinafter referred to as Enhanced Wlink Dedicated CHannel) for supporting high-speed packet data service through uplink. EUDCH is a channel proposed to improve the performance of packet transmission in reverse communication in an asynchronous code division multiple access communication system. A smaller transmission time interval with the Adaptive Modulation and Coding (AMC) and Hybrid Automatic Retransmission Request (HARQ) methods already used in High Speed Downlink Packet Access (HSDPA). It uses new techniques (transmission time interval: ”TTI”). In addition, the base station (Node B) control scheduling of the uplink channel is used. The Node B control scheduling for the uplink is a lot different from the scheduling for the downlink.

Since uplink signals transmitted by a plurality of user terminals (hereinafter, referred to as "UE") are not orthogonal to each other, the uplink signals serve as interference signals. As a result, as the uplink signal received by the Node B increases, the amount of interference signal for the uplink signal transmitted by a specific UE also increases. Therefore, the reception performance of the Node B decreases as the amount of interference signals for the uplink signal transmitted by the specific UE increases. In order to overcome this disadvantage, the uplink transmission power may be increased, but the uplink signal having the increased transmission power serves as an interference signal with respect to other signals. Therefore, the Node B limits the amount of uplink signals that can be received while guaranteeing the reception performance. <Equation 1> represents the amount of uplink signals that can be received while ensuring the reception performance of the Node B.

ROT = I_0 / N_0

I_0 is the total received broadband power spectral density of the Node B, and N_0 represents the thermal noise power spectral density of the Node B. Accordingly, the ROT becomes a radio resource that the Node B can allocate to receive the EUDCH packet data service on the uplink.

1A and 1B show changes in uplink radio resources allocated by Node B. FIG. As shown in FIGS. 1A and 1B, the uplink radio resource that can be allocated by the Node B is represented by the sum of inter-cell interference (ICI), voice traffic, and EUDCH packet traffic.
FIG. 1A illustrates a change in the total ROT when the Node B scheduling is not used. Since the scheduling is not performed on the EUDCH packet traffic, when a plurality of UEs simultaneously transmit the packet data using a high data rate, the total ROT becomes higher than a target ROT. In this case, the reception performance of the uplink signal is degraded.

Figure 1b shows the change in the total ROT when using the Node B scheduling. When using the Node B scheduling, it is possible to prevent the plurality of UEs from simultaneously transmitting the packet data using a high data rate. That is, the Node B scheduling prevents the total ROT from increasing above the target ROT by allowing a lower data rate to other UEs when allowing a higher data rate to a specific UE. Therefore, the Node B scheduling can always be guaranteed a constant reception performance.

The Node B notifies whether EUDCH data can be transmitted for each UE or adjusts the EUDCH data rate by using channel state information indicating a request data rate or uplink transmission quality of UEs using the EUDCH. This Node B scheduling allocates the data rate to the UEs such that the total ROT of the Node B does not exceed a target ROT to improve the performance of the mobile communication system. The Node B may allocate a low data rate for a far-away UE and a high data rate for a far-away UE.

2 illustrates a basic concept of a situation in which Node B scheduling is used for EUDCH. 2, 200 shows Node B supporting EUDCH, and 210 through 216 are UEs using EUDCH. When the data rate of a UE increases, the reception power received by the Node B from the UE increases. Therefore, the ROT of the UE occupies a large part of the total ROT. On the other hand, when the data rate of another UE is lowered, the reception power received by the Node B from the other UE becomes smaller. Therefore, the ROT of the other UE occupies a small portion of the total ROT. The Node B performs Node B scheduling for the EUDCH packet data in consideration of the relationship between the data rate and radio resources and the data rate requested by the UE.

In FIG. 2, the UEs 210 to 216 transmit the packet data at different reverse transmission powers depending on the distance from the Node B 200. The UE 210 farthest from the Node B 200 transmits packet data at the transmit power 220 of the highest reverse channel, and the UE 214 closest to the Node B 200 is the most. The packet data is transmitted at a transmit power 224 of a low reverse channel. The Node B 200 performs scheduling inversely proportional to the strength of the transmit power of the reverse channel and the data rate in order to improve the performance of the mobile communication system while reducing the ICI for other cells while maintaining the total ROT. A relatively small data rate is allocated for the UE 210 having the highest transmit power of the reverse channel, and a relatively high data rate is allocated for the UE 214 having the lowest transmit power of the reverse channel.

3 illustrates an operation in which a UE is allocated a data rate for EUDCH packet data transmission from a Node B and transmits the packet data using the allocated data rate. In step 310, an EUDCH is established between the Node B 300 and the UE 302. Step 310 includes a process of transmitting and receiving messages through a dedicated transport channel. In step 312, the UE 302 transmits a desired data rate, a buffer state, information related to an uplink channel condition, and the like to the Node B 300. Information related to the uplink channel condition includes uplink transmission power and transmission power margin.

The Node B 300 compares the transmission power and the reception power of the uplink channel to estimate a forward channel condition. That is, if the difference between the uplink transmit power and the uplink receive power is small, the reverse channel situation is good. If the difference between the transmit power and the receive power is large, the reverse channel situation is poor. When the UE transmits a transmit power margin to estimate an uplink channel condition, the Node B 300 subtracts the transmit power margin from the maximum possible transmit power of a known UE, thereby subtracting the uplink transmit power. Estimate. The Node B 300 determines the maximum possible data rate for the uplink packet channel of the UE by using the estimated channel condition of the UE and information about the data rate desired by the UE 302.

The determined maximum data rate is informed to the UE 302 in the scheduling assignment information in step 314. The UE 302 determines the data rate of packet data to be transmitted within the range of the maximum possible data rate reported, and transmits the packet data to the Node B 300 at the determined data rate in step 316.

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In order to transmit all packet data stored in the EUCDH data buffer to the Node B, the UE must receive scheduling allocation information from the Node B on a periodic basis. To this end, the UE continuously transmits the buffer status and the uplink channel status (CSI) to the Node B at predetermined scheduling intervals. Transmitting the buffer state and the CSI for each scheduling period causes an overload of uplink signaling, which causes a decrease in the efficiency of uplink packet transmission. Accordingly, there is a need for an efficient scheduling scheme that can prevent the uplink signaling from being overloaded.

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Accordingly, an object of the present invention to solve the above-mentioned problems of the prior art is to propose a method and apparatus for reducing uplink signaling overhead for uplink packet transmission.

Another object of the present invention is to propose a method and apparatus for adjusting a buffer state transmitted on the uplink and a transmission period of a CSI in order to reduce signaling overhead.

Another object of the present invention is to propose a method and apparatus for efficiently transmitting an uplink packet by adjusting a buffer state and a CSI transmission period.

Another object of the present invention is to propose a method and apparatus for efficiently using radio resources by adjusting a buffer state and a transmission period of a CSI.

In a mobile communication system supporting an uplink packet data service to achieve the objects of the present invention, a buffer state and an uplink buffer of a buffer storing packet data to be transmitted by a user terminal for scheduling of the uplink packet data service A method of transmitting a channel state indicating a transmission power of the method, the method comprising receiving different buffer state transmission periods and channel state information transmission periods, and a predetermined threshold or more, in which the amount of packet data stored in the buffer is predetermined; When the buffer state and the channel state are transmitted, and after the buffer state and the channel state are transmitted, the buffer state and the channel state are periodically changed according to the buffer state transmission channel and the channel state transmission period. Characterized in that the process is made to transmit.

In the mobile communication system supporting the uplink packet data service to achieve the above object of the present invention, in the method for the base station receives the buffer state and the channel state from the user terminal for scheduling of the uplink packet data service,
Acquiring different buffer state reception periods and channel state reception periods, determining whether a buffer state and a channel state are first received from the user terminal, and receiving the buffer state and the channel state for the first time from the user terminal; And periodically receiving the buffer state and the channel state according to the buffer state receiving period and the channel state receiving period.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

를 이용하여 칩 레이트로 확산되며, 이득 조정기(gain adjuster)(424)에서 채널이득

과 곱해진 후 합산기(426)으로 입력된다. 상기 EU-DPCCH의 데이터는 확산기(408)에서 EU-DPCCH에 할당된 OVSF 코드

를 이용하여 칩 레이트로 확산되며, 이득 조정기(410)에서 채널이득

과 곱해진 후 상기 합산기(426)으로 입력된다. 상기 합산기(426)는 상기 이득 조정기들(424,410)의 출력 데이터를 합산한 후 I채널에 할당하기 위하여 합산기(420)로 입력한다.
상기 EUDCH 패킷 전송기(406)는 상기 패킷 데이터 전송 포맷에 의해 지정된 양의 패킷 데이터를 상기 EUDCH 데이터 버퍼(400)로부터 읽어내어, 상기 패킷 데이터 전송 포맷에 따라 채널 코딩을 수행하여 EU-DPDCH 데이터를 생성한다. 변조 매핑기(Modulation Mapper)(412)는 상기 EU-DPDCH 데이터에 대해 BPSK, QPSK 또는 8PSK로 변조를 수행하여 EU-DPDCH 변조 심볼 스트림을 출력한다. 여기서 BPSK가 사용되는 경우 상기 변조심볼들은 실수 값을 갖지만, QPSK나 8PSK가 사용되는 경우 상기 변조 심볼들은 복소 값을 갖는다. 하기에서는 상기 EU-DPDCH에 대해QPSK, 8PSK를 사용하는 경우를 설명한다.
상기 변조 매핑기 (412)는 상기EU-DPDCH 데이터를 복소수 심볼 스트림으로 변환한 후 확산기(414)로 전달한다. 상기 확산기(414)는 상기 변조심볼 스트림을 EU-DPDCH에 할당된 OVSF 코드

에 의해 칩 레이트로 확산한다. 상기 확산기(414)의 출력은 이득 조정기(418)에서 채널이득

과 곱해진 후 상기 합산기(420)로 입력된다.
상기 DPDCH의 제어정보를 나타내는 DPCCH 데이터는 확산기(428)에서 DPCCH에 할당된 OVSF 코드

를 이용하여 칩 레이트로 확산되며, 이득 조정기(430)에서 채널이득

과 곱해진다. 상기 이득 조정기(430)의 출력 데이터는 합산기(436)으로 입력된다. 또한 HSDPA 서비스를 위한 제어정보를 포함하는 HS-DPCCH데이터는 확산기(432)에서 HS-DPCCH에 할당된 OVSF 코드

를 이용하여 칩 레이트로 확산되며, 이득 조정기기(434)에서 채널이득

과 곱해진 후 상기 합산기(436)로 입력된다. 상기 합산기(436)는 상기 이득 조정기들(430,434)의 출력 데이터를 합산한 후 Q채널에 할당하기 위하여 상기 위상 변환기(Phase adjuster)(438)로 입력한다. 상기 위상 변환기(438)는 상기 합산기(436)의 출력 데이터에 위상 변화량 j를 곱한 후 상기 합산기(420)로 전달된다.
상기 합산기(420)은 상기 합산기(426)의 출력에 상기 이득 조정기(418)와 상기 위상 변환기(438)의 출력들을 합산하여 생성한 복소 심볼 스트림을 스크램블러(scrambler)(442)로 전달한다. 상기 스크램블러(442)는 상기 복소 심볼 스트림을 스크램블링 코드

를 이용하여 스크램블링한다. 상기 스크램블링된 복소 심볼 스트림은 펄스 형성기(Pulse Shaping Filter)(444)에서 펄스 형태로 변환된 후 RF(Radio Frequency) 유닛(446)을 거쳐 안테나(448)을 통해 상기 Node B로 전달된다.
도 5a는 EUDCH 스케쥴링 할당 정보를 전송하기 위한 스케쥴링 제어 채널(Scheduling Control Channel: EU-SCHCCH)의 구조를 도시한 것이며, 도 5b는 스케쥴링 제어 채널 송신기의 구조를 도시한 것이다. 상기 스케쥴링 제어 채널은 하나의 OVSF 코드를 사용하여 복수 개의 UE들에게 스케쥴링 허용/해제 메시지(Scheduling Grant/Release Message)와 허용된 최대 데이터 레이트(allowed max data rate)를 포함하는 스케쥴링 할당정보(500)를 전송한다. 상기 스케쥴링 허용/해제 메시지는 상기 EUDCH 패킷 데이터의 전송 허용 여부를 나타낸다. 또한 상기 스케쥴링 할당 정보(500)는 상기 스케쥴링 허용/제어 메시지와 상기 허용된 최대 데이터 레이트가 적용될 UE를 나타내는 UE 식별자(UE ID)를 포함한다.
상기 스케쥴링 할당 정보(500)를 포함하는 EU-SCHCCH 데이터(500)는 직/병렬 변환기(510)에서 병렬 심볼 스트림들로 변환된 후 변조 매핑기(512)로 전달된다. 상기 변조 매핑기(512)는 상기 심볼 스트림들을 I, Q 스트림들로 변환한 후 확산기들(514, 516)로 각각 전달한다. 상기 확산기들(514, 516)은 상기 I, Q 스트림을 EU-SCHCCH에 할당된 OVSF 코드

에 의해 칩 레이트로 확산한다. 상기 확산기 (516)로부터 전달된 Q 스트림은 위상 변환기(518)에서 위상 변화량 j와 곱해진 후 합산기(520)로 전달된다. 상기 합산기(520)은 상기 이득 조정기(514)와 위상 변환기(518)의 출력들을 합산하여 생성한 복소 심볼 스트림을 스크램블러(522)로 전달한다. 상기 스크램블러(522)는 상기 복소 심볼 스트림을 스크램블링 코드

를 이용하여 스크램블링한다. 상기 스크램블링된 복소 심볼 스트림은 펄스 형성기(524)에서 펄스 형태로 변환된 후 RF 유닛(526)을 거쳐 안테나(528)을 통해 UE들로 전달된다.
도 6은 전형적인 EUDCH 시스템에서 UE에서 Node B로 버퍼상태와 CSI를 연속적으로 전송하고, 상기 Node B는 상기 UE로 스케쥴링 할당 정보를 전송하는 동작을 도시하고 있다. 상기 UE는 상기 Node B로부터 스케쥴링 할당 정보를 전송받기 위해 상기 버퍼 상태와 CSI를 일정시간(스케쥴링 구간: T_{sch_int}) 간격으로 매번 전송한다.
600시점에서 UE의 EUDCH 데이터 버퍼에 상기 Node B로 전송할 패킷 데이터가 저장(발생)된다. 상기 UE는 602구간에서 상기 데이터 버퍼의 데이터 양을 나타내는 버퍼상태와 상향링크의 송신전력과 전력마진을 나타내는 CSI를 상기 Node B로 전송한다. 상기 Node B는 상기 버퍼상태와 CSI를 이용하여 상기 UE에게 할당할 최대 데이터 레이트를 결정하고, 상기 결정된 최대 데이터 레이트를 스케쥴링 할당 정보에 포함시켜 610구간에서 상기 UE로 통보한다.
상기 EUDCH 데이터 버퍼에 저장되어 있는 패킷 데이터를 한번의 전송으로 상기 Node B로 모두 전송할 수 없을 경우 상기 UE는 상기 Node B에게 스케쥴링 할당을 계속 요구하기 위해 상기 602구간 내지 606구간에서 보이고 있는 바와 같이 상기 버퍼상태와 CSI를 스케쥴링 구간(T_{sch_int}) 간격으로 연속하여 전송한다. 상기 606시점 이후에는 EUDCH 데이터 버퍼에 저장되어 있는 패킷 데이터를 모두 전송하였으므로 상기 UE는 상기 버퍼상태와 CSI의 전송을 중단한다. 상기 Node B는 상기 UE로부터 버퍼상태와 CSI를 전달받더라도 ROT조건이 맞지 않는 경우 612 구간에 나타낸 바와 같이 상기 스케쥴링 할당 정보를 전송하지 않는다.
여기에서 버퍼상태와CSI는 매 스케쥴링 구간마다 전송된다. 그러나 이러한 전송은 상향링크 오버헤드를 크게 증가시켜 상향링크 트래픽 용량을 감소시키게 된다. 따라서 본 발명의 바람직한 실시예에서는 상기 버퍼 상태와 CSI에 대해 각각 개별적으로 설정된 전송주기들을 사용한다. 여기서 버퍼상태와 CSI에 대해 서로 다른 전송주기들을 설정하는 이유를 설명하면 다음과 같다.
먼저 상향링크(Uplink: UL) 전력제어의 관점에서 설명한다.
Node B는 UE로부터 전송되는 상향링크 신호를 지속적으로 측정하고, 상기 측정 결과에 따라 상기 UE로 상향링크 전력제어(Uplink Transmit Power Control: UL TPC) 명령을 전송한다. 상기 UE는 상기 Node B로부터 상기 TPC를 수신하고, 상기 TPC가 송신전력을 낮추라는 명령이면 하향링크 송신전력을 감소시키며, 상기 TPC가 송신전력을 높이라는 명령이면 하향링크 송신전력을 증가시킨다. 따라서 상기 UE로부터 CSI가 수신되지 않는 구간에서, Node B는 하기 〈수학식 2〉에 의해 상기 UE의 송신전력을 추정할 수 있다.
Transmit_power_est = CSI_prev+power_control_step_size× (up_count-down_coumt)
상기 Transmit_power_est는 상기 UE의 전송전력 추정값이며, 상기 CSI_prev는 이전에 수신한 상기 UE의 송신 전력 정보이다. 상기 up_count는 상기 CSI_prev를 수신한 이후 송신전력을 증가시키라고 명령한 횟수를 나타내며, 상기 down_coumt는 상기 CSI_prev를 수신한 이후 송신전력을 감소시키라고 명령한 횟수를 나타낸다. 상기 power_control_step_size는 한번의 명령에 의해 감소 또는 증가되는 송신전력의 단위 양을 나타낸다. 상기 〈수학식 2〉에서 보이고 있는 바와 같이 상기 Node B는 상기 이전에 수신한 UE의 전송 파워와 상기 Node B가 명령한 송신전력에 관한 명령들을 이용하여, 상기 UE의 현재 전송전력을 추정한다.
하지만 상기 UE가 소프트 핸드오버 영역에 있을 경우, 상기한 <수학식 2>는 적용될 수 없다 이를 하기 도 7을 참조하여 설명한다.In the present invention, for the Node B control scheduling of an enhanced uplink dedicated transport channel (EUDCH) for high speed uplink packet data service in a wideband code division multiple access communication system, a buffer state and a CSI of a UE are transmitted from the UE to the Node B. The transmission periods are set differently, and the buffer state and the CSI are transmitted according to the set transmission periods. A radio network controller (RNC) controlling a radio resource of a Node B sets the buffer states and the transmission periods of the CSI in consideration of service quality required for EUDCH service, uplink ROT, and UE handover. .
4 illustrates a transmitter structure of a user terminal supporting EUDCH service. In the user terminal, the reverse physical channels are a dedicated physical data channel (DPDCH), a dedicated physical data channel (EU-DPDCH) for an EUDCH service, a dedicated physical control channel (DPCCH), and an HSDPA service. Dedicated physical control channel (High Speed DPDCH: HS-DPCCH) for, and a dedicated physical control channel (EU-DPCCH) for EUDCH service are used.
The EU-DPCCH is a physical control channel for an EUDCH service and includes channel state information including a buffer state of a UE and uplink transmit power and uplink transmit power margin required for the Node B to estimate an uplink channel condition. Information: CSI) is transmitted. In addition, the EU-DPCCH transmits a packet data transport format factor (E-TFRI) indicating a transport format such as data size, code rate, and modulation scheme for the EU-DPDCH. The EU-DPDCH carries packet data using a data rate determined according to scheduling allocation information received from the Node B. The DPDCH supports only Binary Phase Shift Keying (BPSK) modulation, but the EU-DPDCH supports Quadrature Phase Shift Keying (QPSK), 8PSK (QPSK) as well as the BPSK to increase the data rate while maintaining the number of spreading codes transmitted simultaneously. Higher modulation schemes such as 8-ary PSK) can be supported.
The EUDCH transmission controller 404 monitors the EUDCH data buffer 400 in which data to be transmitted to EUDCH is stored to obtain a buffer state necessary for scheduling Node B control, and also an uplink transmission path (not shown). CSI). The EUDCH Transmission Controller 404 also determines an E-TFRI indicating a packet data transmission format for the EUDCH. The packet data transmission format is determined according to the maximum data rate allowed by the scheduling allocator 402. The EUDCH transmission controller 404 generates EU-DPCCH data including the buffer state, the CSI, the E-TFRI, and inputs the multiplier 408 into the multiplier 408.
The data of the DPDCH is orthogonal variable spreading factor (OVSF) code assigned to the DPDCH in a spreader 422.

Is spread at chip rate, and channel gain at gain adjuster 424

Multiplied by and input to summer 426. The data of the EU-DPCCH is assigned to the OVSF code assigned to the EU-DPCCH at the spreader 408.

Spread at chip rate, and gain gain 410 is channel gain

Multiplied by and input to summer 426. The summer 426 sums the output data of the gain adjusters 424 and 410 and inputs the summer 420 to the summer 420 for allocation to the I channel.
The EUDCH packet transmitter 406 reads the packet data of the amount specified by the packet data transmission format from the EUDCH data buffer 400 and performs channel coding according to the packet data transmission format to generate EU-DPDCH data. do. A modulation mapper 412 modulates the EU-DPDCH data with BPSK, QPSK, or 8PSK to output an EU-DPDCH modulation symbol stream. Here, the modulation symbols have a real value when BPSK is used, but the modulation symbols have a complex value when QPSK or 8PSK is used. Hereinafter, a case of using QPSK and 8PSK for the EU-DPDCH will be described.
The modulation mapper 412 converts the EU-DPDCH data into a complex symbol stream and forwards it to the spreader 414. The spreader 414 assigns the modulation symbol stream to the OVSF code assigned to the EU-DPDCH.

Diffuses at the chip rate. The output of the spreader 414 is channel gained at the gain adjuster 418.

Multiplied by and is input to the summer 420.
The DPCCH data representing the control information of the DPDCH is an OVSF code allocated to the DPCCH in the spreader 428.

Is spread at the chip rate, and the channel gain in the gain adjuster 430

Multiplied by The output data of the gain adjuster 430 is input to the summer 436. In addition, the HS-DPCCH data including control information for the HSDPA service is assigned to the HS-DPCCH in the spreader 432 by the OVSF code.

Spread at the chip rate using the channel gain in the gain adjuster 434

Multiplied by and input to summer 436. The adder 436 adds the output data of the gain adjusters 430 and 434 and inputs it to the phase adjuster 438 for allocation to the Q channel. The phase shifter 438 multiplies the output data of the summer 436 by the phase change amount j and then transfers the result to the summer 420.
The summer 420 delivers a complex symbol stream generated by summing outputs of the gain adjuster 418 and the phase shifter 438 to the output of the summer 426 to a scrambler 442. . The scrambler 442 scrambling the complex symbol stream

Scrambling using The scrambled complex symbol stream is converted into a pulse shape in a pulse shaping filter 444 and then transmitted to the Node B through an antenna 448 via a radio frequency (RF) unit 446.
FIG. 5A illustrates a structure of a scheduling control channel (EU-SCHCCH) for transmitting EUDCH scheduling allocation information, and FIG. 5B illustrates a structure of a scheduling control channel transmitter. The scheduling control channel includes scheduling allocation information 500 including a scheduling grant / release message and an allowed maximum data rate to a plurality of UEs using one OVSF code. Send it. The scheduling allow / release message indicates whether to allow transmission of the EUDCH packet data. The scheduling assignment information 500 also includes a UE identifier (UE ID) indicating a UE to which the scheduling allow / control message and the allowed maximum data rate are to be applied.
The EU-SCHCCH data 500 including the scheduling assignment information 500 is converted into parallel symbol streams in the serial / parallel converter 510 and then transferred to the modulation mapper 512. The modulation mapper 512 converts the symbol streams into I and Q streams and forwards them to spreaders 514 and 516, respectively. The spreaders 514 and 516 assign OVSF codes to the I and Q streams to EU-SCHCCH.

Diffuses at the chip rate. The Q stream delivered from the diffuser 516 is multiplied by the phase change amount j in the phase converter 518 and then passed to the summer 520. The summer 520 delivers the complex symbol stream generated by summing the outputs of the gain adjuster 514 and the phase converter 518 to the scrambler 522. The scrambler 522 scrambling the complex symbol stream

Scrambling using The scrambled complex symbol stream is converted into pulse form in the pulse shaper 524 and then passed to the UE through the antenna 528 via the RF unit 526.
FIG. 6 illustrates an operation of continuously transmitting a buffer state and CSI from a UE to a Node B in a typical EUDCH system, and transmitting the scheduling allocation information to the UE. The UE transmits the buffer state and the CSI every time at a predetermined time interval (scheduling interval: T _{sch_int} ) so as to receive scheduling allocation information from the Node B.
At 600, packet data to be transmitted to the Node B is stored (generated) in the EUDCH data buffer of the UE. The UE transmits, to the Node B, a buffer state indicating a data amount of the data buffer, a CSI indicating a transmission power, and a power margin of the uplink in the section 602. The Node B determines the maximum data rate to allocate to the UE using the buffer state and the CSI, and includes the determined maximum data rate in scheduling allocation information to notify the UE in section 610.
If the packet data stored in the EUDCH data buffer cannot be completely transmitted to the Node B in one transmission, the UE as shown in the sections 602 to 606 to continue requesting scheduling allocation to the Node B. The buffer status and CSI are transmitted continuously at the scheduling interval (T _{sch_int} ) interval. After the 606 time point, since all packet data stored in the EUDCH data buffer has been transmitted, the UE stops transmitting the buffer state and the CSI. The Node B does not transmit the scheduling allocation information as shown in section 612 when the ROT condition is not met even though the buffer state and the CSI are received from the UE.
Here, the buffer status and the CSI are transmitted in every scheduling interval. However, such transmission greatly increases uplink overhead, thereby reducing uplink traffic capacity. Therefore, the preferred embodiment of the present invention uses transmission periods that are set separately for the buffer state and the CSI. The reason for setting different transmission periods for the buffer state and the CSI is as follows.
First, an uplink (UL) power control will be described.
The Node B continuously measures an uplink signal transmitted from the UE and transmits an uplink transmit power control (UL TPC) command to the UE according to the measurement result. The UE receives the TPC from the Node B, and reduces the downlink transmission power if the TPC command to lower the transmission power, and increases the downlink transmission power if the TPC command to increase the transmission power. Therefore, in a section in which CSI is not received from the UE, the Node B may estimate the transmission power of the UE by Equation 2 below.
Transmit_power_est = CSI_prev + power_control_step_size × (up_count-down_coumt)
The Transmit_power_est is an estimated transmit power of the UE, and the CSI_prev is a previously received transmit power information of the UE. The up_count represents the number of times that the transmission power is increased after receiving the CSI_prev, and the down_coumt represents the number of times that the transmission power is decreased after receiving the CSI_prev. The power_control_step_size represents a unit amount of transmission power that is decreased or increased by one command. As shown in Equation 2, the Node B estimates a current transmit power of the UE by using commands related to the previously received UE's transmit power and the Node B commanded transmit power.
However, when the UE is in the soft handover region, Equation 2 cannot be applied. This will be described with reference to FIG. 7.

7 illustrates an uplink power control operation of a UE located in a soft handover region. The UE 720 located in the handover area transmits data to at least two active Node Bs (here, three active Node Bs 710, 712, 714) associated with the handover area. The active Node Bs 710-714 receive the data transmitted from the UE, demodulate the received data and forward it to the RNC 700. This approach allows macro selection diversity by having an active Node B demodulating the received data out of the Active Node Bs 710-714 without error transmits the demodulated data to an RNC 700. You can benefit.

The UE 720 receives three downlink power control commands (TPCs) from the active Node Bs 710-714. The UE 720 reduces the transmission power if any one of the three TPCs is a command to lower the transmission power. In addition, the UE 720 increases the transmission power if all three TPCs are commands to increase the transmission power.

delete

However, since each active Node B 710-714 can not know the power control commands transmitted by other active Node Bs, each Active Node B 710-714 is estimated by Equation 2, and the UE 720 is estimated. ) Transmit power is different from the actual transmit power of the UE (720). For this reason, the UE 720 uses a shorter CSI transmission period in order for the active Node Bs 710-714 to correctly recognize the transmission power of the UE 720 in the handover region. shall.
On the other hand, in a section in which no buffer status is reported from the UE, the Node B estimates the buffer status of the UE as shown in Equation 3 using the buffer status previously reported from the UE.

Buffer_state_est = Buffer_state_prev-Data_sent

The Buffer_state_est is a buffer state estimate and the Buffer_state_prev is a previously received buffer state value. The Data_sent means the amount of data received from the UE after the Buffer_state_prev is received and is obtained by using the E-TFRI values received from the UE. Since the E-TFRI indicates a data size, a code rate, a modulation scheme, etc. of the EU-DPDCH, the amount of data received from the UE can be known according to the data size. The E-TFRI is generally transmitted to have a reception error rate lower than that of the power control command in order to increase the reception performance of packet data. Therefore, the buffer state estimation value of the UE by the Node B has a relatively high reliability compared to the transmission power estimation value. For this reason, the buffer state transmission period may be longer than the CSI transmission period.

8 illustrates an operation of setting a buffer state transmission period and a CSI transmission period in an RNC according to an embodiment of the present invention.

In step 800, the RNC determines a buffer status transmission period (T _buffer ) for the UE requesting the EUDCH service in consideration of ROT conditions and quality of service (QoS) required for EUCDH service. Herein, the ROT condition indicates whether the measured ROT exceeds a predetermined target ROT. In step 802, the RNC determines whether the UE is located in a handover area. If the UE is located in the handover area as a result of the determination, go to step 804; and if it is not located in the handover area, go to step 806 if the UE is located in the handover area.

In step 804, the RNC sets a CSI transmission period (T _CSI ) for the UE to be equal to a scheduling interval length (T _{sch_int} ). In step 806, the RNC calculates the CSI transmission period T _CSI as shown in Equation 4 below.

는 A이하의 최대 정수를 구하는 함수이다. 상기

는 E-TFRI의 요구되는 수신 에러 레이트이며, 상기

는 UE로 전송되는 전력제어명령(TPC)의 요구되는 수신 에러 레이트이다. 상기 〈수학식 4〉와 같이 상기 CSI 전송주기(T_CSI)는 상기 E-TFRI의 수신 에러 레이트와 UE로 전송되는 전력제어명령의 수신 에러 레이트에 따라 상기 버퍼상태 전송주기(T_buffer)보다 작도록 설정된다. 상기 RNC는 상기 버퍼상태 전송주기(T_buffer)와 상기 CSI 전송주기(T_CSI)를 RRC 시그널링 메시지를 이용하여 상기 UE로 전달하며, NBAP(Node B Application Part) 시그널링을 이용하여 상기 Node B로 전송한다.remind

Is a function that finds the maximum integer less than or equal to A. remind

Is the required reception error rate of the E-TFRI,

Is the required reception error rate of the power control command (TPC) sent to the UE. As shown in Equation 4, the CSI transmission period T _CSI is smaller than the buffer state transmission period T _buffer according to the reception error rate of the E-TFRI and the reception error rate of the power control command transmitted to the UE. It is set to. The RNC transmits the buffer state transmission period (T _buffer ) and the CSI transmission period (T _CSI ) to the UE using an RRC signaling message, and transmits to the Node B using NBAP (Node B Application Part) signaling. do.

In the example described above, the buffer state transmission period is set longer than the CSI transmission period. However, considering that the temporary channel change due to fading phenomenon is overcome by the power control in the CDMA system, Node B control scheduling has a long term fading such as shadowing due to geographic effects. Phenomena, or changes in average channel conditions over a long period of time. In this case, the CSI reflects the average channel situation for a long time.

As described above, when the CSI indicates an average channel condition for a long time, the CSI transmission period may be set longer than the buffer state transmission period.
In the above, the case where the CSI transmission period is shorter than the buffer state transmission period and the case where the CSI transmission period is longer than the buffer state transmission period have been described. However, it should be understood that the main gist of the present invention is to set the CSI transmission period and the buffer state transmission period differently depending on the case, and it should be noted that the above-described cases do not limit the scope of the present invention.
Hereinafter, when the buffer state transmission period and the CSI transmission period are set differently, a detailed operation and system structure for transmitting the buffer state and the CSI according to the transmission periods will be described in detail.

9 is a diagram illustrating a code block including a CSI and a buffer state transmitted from a UE according to an embodiment of the present invention. As shown in FIG. 9, the buffer status and the CSI are transmitted during one scheduling period. Here, the one scheduling interval is 10 ms. In order to differentiate the buffer state transmission period and the CSI transmission period, the UE performs channel encoding on the buffer state and the CSI through separate coding chains.
In this case, the buffer state is subjected to channel coding after adding a CRC, and the CSI is subjected to channel coding without adding a CRC. The Node B recognizes that the buffer status is transmitted through the CRC check. Since the CSI is located at the rear end of the buffer state and transmitted, it can be known whether the CSI is received or not.

  Hereinafter, an operation of a UE according to a preferred embodiment of the present invention will be described.

1. If the amount of packet data stored in the EUCDH data buffer is above a predetermined threshold for scheduling, the UE starts to send the buffer status and CSI to Node B.

2. After the UE transmits the buffer state and the CSI, the UE repeatedly performs the buffer state and the CSI transmission according to a set transmission period (transmission period transmitted by the RNC to the UE). As described above, the buffer state and the transmission period of the CSI may vary according to the transmission period notified by the RNC.

3. The UE checks the EU-SCHCCH to see if scheduling allocation information is transmitted from the Node B after transmitting the buffer status and the CSI.

4. If the packet data amount of the EUDCH data buffer is reduced below the threshold, the UE stops buffering and CSI transmission. In other cases, the buffer state and the CSI transmission are stopped even when a scheduling release message indicating that Node B scheduling is stopped is received from the Node B.

The operation of Node B is as follows.

1. Node B continuously performs CRC check of EU-DPCCH to determine whether buffer status is transmitted from UE. When the buffer state is detected in any one of the scheduling periods by the CRC check, the CSI is received after the buffer state of the scheduling period.

2. When Node B first receives the buffer status and the CSI, the Node B receives the buffer status and the CSI in predetermined scheduling intervals according to preset reception periods (the reception periods notified to the Node B by the RNC). As described above, scheduling periods in which the buffer status is received may not coincide with scheduling periods in which the CSI is received. The Node B generates scheduling assignment information using the buffer state and the CSI.

3. The Node B estimates the amount of packet data stored in the EUDCH data buffer of the UE by Equation 3, and stops receiving the buffer state and the CSI if it is determined that the estimate is less than or equal to a predetermined threshold. do.

4. In other cases, Node B sends an unscheduling message to the UE to suspend the buffer state and CSI transmission.

10 shows an example of EU-DPCCH signaling for scheduling allocation between a UE and a Node B according to a preferred embodiment of the present invention. Here, CNT _{sch_int} is a scheduling interval index that distinguishes scheduling intervals, and each scheduling interval includes an area for transmitting a buffer state and an area for transmitting CSI.
In the 1010 interval where CNT _{sch_int} = 10, the UE recognizes that the amount of packet data stored in the EUDCH data buffer exceeds a threshold for scheduling, and transmits the buffer state and the CSI to the Node B for the first time. Thereafter, the UE periodically transmits a buffer state and a CSI to the Node B according to a buffer state transmission period and a CSI transmission period, respectively. Since the transmission period of the buffer state is 8 times the scheduling interval length (T _{sch_int} ), the buffer state is CNT _{sch_int} is transmitted in intervals _{1010,1014,1018} with 10,18,26, and the transmission period of the CSI is 4 times the scheduling interval length, so CSI is CNT _{sch_int} with 10,14,18,22,26. Segments 1010, 1012, 1014, 1016, and 1018 are transmitted.

After first receiving the buffer state and the CSI, the Node B periodically receives the buffer state and the CSI from the UE according to the buffer state notified from the RNC and the reception periods of the CSI. In the 1000 and 1002 intervals, the Node B determines scheduling allocation information in consideration of the most recently reported buffer state, CSI, and ROT situation, and transmits the scheduling allocation information to the UE.

If the Node B estimates the amount of data stored in the EUDCH data buffer of the UE by Equation 3, and determines that the UE has transmitted all the packet data stored in the EUDCH data buffer, scheduling allocation information Is no longer sent to the UE. At this time, the Node B may notify the UE of a scheduling release message indicating that scheduling assignment information is no longer transmitted to the UE, as in the interval 1004. Upon receiving the unscheduling message, the UE stops transmitting a buffer state and CSI to the Node B. The Node B continues to perform a CRC check for each scheduling period of EU-DPCCH to determine whether a new buffer state is received from the UE even after the scheduling is stopped.

When the Node B does not use the scheduling assignment message, the UE stops transmitting the buffer state and the CSI when the packet data stored in the EUDCH data buffer falls below the threshold.

In the embodiment of FIG. 10, the time point at which periodic transmission of the buffer state and the CSI is started is based on the buffer state transmitted first. In contrast, in another embodiment of the present invention, the transmission time of the buffer state and the CSI is determined through the following process separately from the buffer state transmitted first. Equation 5 below is an equation for determining the transmission time of the buffer state, and Equation 6 below is an equation for determining the transmission time of the CSI.

Mod is the operator to find the remainder. The CNT _{sch_int} is a scheduling interval number for identifying scheduling intervals. The offset_buffer is an integer value that is set as differently as possible for each UE in order to prevent buffer states from a plurality of UEs providing EUDCH services from being transmitted at the same time and increasing the measured ROT of Node B at that time. . Each UE transmits a buffer state to the Node B in predetermined scheduling intervals satisfying Equation 5 according to the offset_buffer set to the UEs. Similarly, the offset_CSI is an integer value that is set as differently as possible for each of the UEs in order to prevent CSIs transmitted from the plurality of UEs at the same time and increase the measured ROT of the Node B at the time. Each UE transmits CSI to the Node B in designated scheduling intervals satisfying Equation 6 according to the offset_CSI set in the UE. The offset_buffer and the offset_CSI are set equal to or different from each other.

11 illustrates an operation of transmitting a buffer state and a CSI according to another embodiment of the present invention. The UE shown in FIG. 11 has offset_buffer and offset_CSI set to 0, respectively. In addition, the buffer state transmission period is 8 times the scheduling interval length, and the CSI transmission period is the 4 times scheduling interval length. Then, the transmission time points 1106 and 1108 of the buffer state by Equation 5 are CNT _{sch_int} = 16 and 24, and the transmission time points of the CSI by Equation 6 to 1105, 1106, _{1107 and} 1108. , 1109), CNT _{sch_int} = 12, 16, 20, 24, 28. After the UE first transmits the buffer state and the CSI in the interval 1104, the UE transmits the CSI in the intervals 1105, 1106, 1107, 1108, and 1109, and transmits the buffer state in the intervals 1106 and 1108.

12 illustrates a structure of an EUDCH transmission controller 1200 of a UE according to a preferred embodiment of the present invention.

Referring to Figure 12, the transmission start and end determiner 1202 determines the start time and end time of the buffer status and CSI transmission. The starting point is determined by comparing the input buffer state with a predetermined threshold. When the buffer state (amount of packet data stored in the EUDCH data buffer) exceeds the threshold, the transmission start and end decision unit 1202 determines that the buffer state and the transmission start time of the CSI have been reached to determine a start signal. Output The end time point is a time point for receiving a unscheduling message from the Node B. In other cases, when the buffer state is less than or equal to the threshold value, the transmission start and end decision unit 1202 determines that the buffer state and the transmission end time of the CSI have been reached and outputs an end signal.

The transmission time determiner 1204 determines the transmission time of the buffer state and the CSI when the start signal is output from the transmission start and end determiner 1202. The buffer status and the time of transmission of the CSI are represented by CNT _{sch_int} as shown in FIGS. 10 and 11. The buffer state and transmission periods T _buffer , T _CSI of the _CSI are transferred from the RNC to the transmission time determiner 1204 through higher layer signaling. The transfer time determiner 1204 turns on the buffer state transfer switch 1206 in the scheduling periods corresponding to the buffer state transfer time when the buffer state transfer time is determined. In addition, when the CSI transmission time is determined, the transmission time determiner 1204 turns on the CSI transmission switch 1214 in the scheduling periods corresponding to the CSI transmission time.

When the buffer state transfer switch 1206 is turned on, the buffer state is input to the CRC adder 1208. The buffer state is channel coded in the channel coding unit 1210 after the CRC is added in the CRC adding unit 1208. The channel coded buffer state is input to a multiplexer 1212. When the CSI transmission switch 1214 is turned on, the CSI is channel coded by the channel coding unit 1216 and then input to the multiplexer 1212. An EUDCH transmission format (TF) determiner 1218 determines a transmission format of packet data for the EUDCH service by using the scheduling assignment information transmitted from the Node B, and a transmission format factor (E-TFRI) indicating the determined transmission format. ) The transmission format factor E-TFRI is channel coded in the channel coding unit 1222 after the CRC is added in the CRC adding unit 1220. The channel coded transmission format factor is input to the multiplexer 1212. The multiplexer 1212 multiplexes the encoded buffer state, the CSI, and the transmission format factor and transmits the same through the EU-DPCCH. Meanwhile, the EUDCH packet transmitter 1224 transmits the packet data stored in the EUDCH data buffer using the transmission format determined by the EUDCH transmission format determiner 1218.
13 illustrates the operation of the UE transmitter in accordance with a preferred embodiment of the present invention.

Referring to FIG. 13, in step 1300, the UE monitors the buffer status, that is, the amount of packet data stored in the EUDCH data buffer. In step 1302, the UE determines whether the amount of packet data stored in the EUDCH data buffer is greater than or equal to a predetermined threshold. If the amount of packet data is greater than or equal to the threshold as a result of the determination, the method proceeds to step 1306. If the amount of packet data stored in the EUDCH data buffer is smaller than the threshold, the process proceeds to step 1304. At 1304, the UE waits until the next scheduling interval, and then returns to step 1300 to observe the EUDCH data buffer.

In step 1306, the UE transmits the buffer state and the CSI, and moves to step 1308. After waiting for the next scheduling interval in step 1308, the UE observes the EUDCH data buffer in step 1310. In step 1312, the UE determines whether to continue transmitting the buffer state and the CSI. The determination is made by comparing the threshold with the amount of packet data stored in the EUDCH data buffer as described above. If the amount of packet data is still above the threshold, the UE moves to step 1314 to continue transmitting the buffer state and CSI, and if the amount of packet data is less than the threshold, the UE is in the buffer state. In step 1322 to stop CSI transmission. In step 1322, the UE determines whether to continue the reverse packet transmission service. If it is determined that the reverse packet transmission service continues, the process moves to step 1324 and waits until the next scheduling interval. If it is determined that the reverse packet forwarding service is not continued, the operation ends.
In step 1314, the UE determines whether the current scheduling interval number matches the buffer status transmission time determined according to the buffer status transmission period transmitted from the RNC. As a result of the determination, if the current scheduling interval number coincides with the buffer state transmission time, the process moves to step 1316; In step 1316, the UE transmits a buffer state and moves to step 1318.

In step 1318, the UE determines whether the current scheduling interval number matches the CSI transmission time point according to the CSI transmission period transmitted from the RNC. As a result of the determination, if the current scheduling interval number coincides with the CSI transmission time point, the process moves to step 1320; In step 1320, the UE transmits CSI, and returns to step 1308.

14 shows a reception device of a Node B according to a preferred embodiment of the present invention.
Referring to FIG. 14, the antenna 1400 receives an RF signal transmitted by a UE and transmits the received RF signal to the RF unit 1402. The RF unit 1402 converts the RF signal into a baseband signal and transmits the RF signal to a pulse shaping filter 1404. The pulse former 1404 converts the baseband signal into a digital signal and delivers the descrambler 1406. The descrambler 1406 descrambles the digital signal using a scrambling code C _scramble . The descrambled signal is multiplied by the despreader 1408 with the OVSF code C _OVSF , passed through the channel compensator 1410, and then transmitted to the demultiplexer 1412. The demultiplexer 1412 separates the signal transmitted from the channel compensator 1410 into an encoded buffer state, CSI, and E-TFRI. Since the CSI receiving switch 1414 and the buffer state receiving switch 1416 are initially on, the buffer state and the CSI are respectively transferred to the buffer state channel decoding unit 1422 and the CSI channel decoding unit 1420. Delivered.

The encoded buffer state is channel decoded by the buffer state channel decoding unit 1422. A buffer state CRC Checker 1426 detects a CRC for the buffer state. The CRC checker 1426 transmits the CRC detection result value to the reception time controller 1434. The reception point controller 1434 determines whether a buffer status is transmitted from the UE by using the CRC detection result value. If the CRC detection result value is successful, that is, when it is determined that the buffer status is transmitted from the UE, the reception time controller 1434 determines that the reception start time and the CNT _{sch_int} and T _buffer , T _SCI , and THRES _buffer . Determine the buffer status and the reception time of CSI using. Only at the determined reception point, the buffer state receiving switch 1416 and the CSI receiving switch 1414 are turned on, respectively.
The CSI channel decoder 1420 channel-decodes the encoded CSI and transfers the same to the EUDCH scheduler 1430. The EUDCH scheduler 1430 generates scheduling allocation information by using the CSI transmitted from the CSI channel decoding unit 1420 and the buffer state transferred from the buffer state CRC detector 1426. The scheduling assignment information is transmitted to the UE through a scheduling control channel (EU-SCHCCH). The E-TFRI channel decoding unit 1418 channel-decodes the encoded E-TFRI transmitted from the demultiplexer 1412 and transmits the encoded E-TFRI to the E-TFRI CRC checker 1424. The E-TFRI CRC checker 1424 performs a CRC check on the E-TFRI, and if the CRC check is successful, provides the E-TFRI to the EUDCH data decoding unit 1428.
The EUDCH data decoding unit 1428 decodes EUDCH data received from the UE through EU-DPDCH using the E-TFRI.

The UE buffer state estimator 1432 estimates the buffer state of the UE by using the buffer state and the E-TFRI transmitted from the buffer state CRC detector 1426. The buffer state estimate is passed to the reception point controller 1434. The reception time controller 1434 determines the reception end time when the buffer state estimate is smaller than the threshold value, and controls a scheduling control channel (EU-SCHCCH) transmitter (FIG. 5b) to transmit a scheduling release message to the UE. do.
15 illustrates an operation of receiving a buffer state and a channel state at a Node B according to a preferred embodiment of the present invention.

Referring to FIG. 15, in step 1500, the Node B channel decodes an encoded buffer state transmitted by a UE. In step 1502, the Node B performs a CRC check on the buffer state and moves to step 1504. In step 1504, the Node B determines whether the UE transmits a buffer state in the current scheduling period by using the CRC check result. If the CRC check is successful as a result of the determination, the buffer state is transmitted to the scheduler, and then the procedure proceeds to step 1506. If the CRC check fails, the procedure proceeds to step 1508. In step 1508, the Node B waits for the next scheduler interval and returns to step 1500.
In step 1506, the Node B performs channel decoding on the received CSI following the buffer state, detects the CSI, transfers the detected CSI to the scheduler, and waits for the next scheduling interval in step 1510. In step 1512, the Node B estimates the buffer state of the UE by using the most recently received buffer state and the received data amount. The received data amount can be known from the E-TFRI, and the remainder obtained by subtracting the received data amount from the most recently received buffer state becomes a buffer state estimate of the UE.

In step 1514, the Node B determines whether the buffer state estimate has a value equal to or greater than a predetermined threshold. If it is determined that the buffer state estimate of the UE has a value greater than or equal to the threshold value, the method proceeds to step 1516. If the buffer state estimate of the UE is less than the threshold value, the procedure proceeds to step 1526 and a release scheduling message to the UE. After transmitting, go to step 1528. In this case, the step 1526 is indicated by a dotted line, indicating that step 1526 may be selectively performed. If you do not perform step 1526, go to step 1528 to step 1528. In step 1528, the Node B determines whether to continue the uplink packet transmission service. If it is determined that the uplink packet transmission service is to be continued, the process moves to step 1530, waits until the next scheduling interval, and returns to step 1500. If it is determined that the uplink packet transmission service is to be stopped, the operation ends.
In step 1516, the Node B determines whether the current scheduling interval is a buffer state reception time. If it is determined that the buffer state is received at step 1518, the process proceeds to step 1518. In step 1518, the Node B receives a buffer state in the current scheduling interval and performs a decoding process. In step 1520, the Node B performs a CRC check on the decoded buffer state. If the CRC check is successful, the buffer status is input to the scheduler.

In step 1522, the Node B determines whether the current scheduling interval is a CSI reception time. If it is determined that the CSI is received, the process proceeds to step 1524 to receive the CSI in the current scheduling interval and performs a channel decoding process. If it is determined that the CSI is received, the process returns to step 1510.

16 illustrates a structure of an EU-SCHCCH receiver of a UE that receives scheduling allocation information transmitted from a Node B according to an embodiment of the present invention.
Referring to FIG. 16, the antenna 1600 receives an RF signal including scheduling assignment information transmitted by the Node B and transmits the RF signal to the RF unit 1602. The RF unit 1602 converts the RF signal into a baseband signal and transmits the converted RF signal to a pulse generator 1604. The pulse former 1604 converts the baseband signal into a digital signal and delivers the descrambler 1606. The descrambler 1606 descrambles the digital signal using a scrambling code C _scramble . The descrambled signal is passed to the EU-SCHCCH channel decoder 1614 after passing through the switch 1608 and passing through the despreader 1610 and the channel compensator 1612. The operation of the switch 1608 will be described later.
The EU-SCHCCH channel decoder 1614 performs a channel decoding process on the data transmitted from the channel compensator 1612 and then transfers the decoded data to the EU-SCCCH CRC detector 1616. The EU-SCCCH CRC checker 1616 determines whether scheduling allocation information has been received from the Node B by performing a CRC check on the decoded data. If the CRC check result is successful, the EU-SCCCH CRC checker 1616 determines that the decoded data includes scheduling allocation information, detects the scheduling allocation information, and transmits the scheduling allocation information to the EUDCH transmission controller 1618. If the scheduling assignment information includes a scheduling release message, the EU-SCHCCH CRC checker 1616 detects the scheduling release message and transmits the scheduled release message to the scheduling assignment reception controller 1620.

The scheduling assignment reception controller 1620 receives a buffer state of the EUDCH data buffer, a predetermined threshold THRES _buffer , and a buffer state report flag. The buffer status report flag is activated when the transmitting side of the UE transmits the first buffer status to the Node B. When the first buffer state is transmitted to the Node B by the buffer status report flag, the scheduling allocation receiving controller 1620 turns on the switch 1608 to schedule scheduling information transmitted from the Node B. Receive The scheduling assignment reception controller 1620 controls the switch 1608 by using the buffer state and the threshold value. That is, when the buffer state is greater than or equal to the threshold value, the switch 1608 is turned on to receive scheduling allocation information transmitted from the Node B. The switch 1608 is turned off when the buffer state is less than the threshold. The scheduling assignment receiving controller 1620 receives the unscheduling message from the EU-SCHCCH CRC checker 1616. Turn off 1608.

17 illustrates the operation of an EU-SCHCCH receiver of a UE according to a preferred embodiment of the present invention.
Referring to FIG. 17, in step 1700, the UE determines whether a reception start condition of scheduling allocation information is satisfied. The reception start condition is a point in time at which the buffer status report flag is activated. If the buffer status report flag is activated, the process proceeds to step 1702. Otherwise, the process proceeds to step 1704 to wait until the next scheduling interval.

In step 1702, the UE performs channel decoding on EU-SCHCCH received data, and then moves to step 1704 to perform a CRC check on the decoded data. If it is determined that the decoded data is the scheduling allocation information by the CRC check, the control proceeds to step 1710. If it is determined that the decoded data is not the scheduling allocation information, the operation proceeds to step 1712. In step 1710, the UE delivers the scheduling assignment information to an EUDCH transmission controller. In step 1712, the UE waits for the next scheduling interval, and then moves to step 1714.
In step 1714, the UE observes the buffer status of the EUDCH data buffer. The buffer status observation is made by comparing a predetermined threshold with the amount of packet data stored in the EUDCH data buffer. In step 1716, the UE determines whether to continue receiving scheduling allocation information according to the comparison result. In addition, the UE determines whether to continue receiving scheduling allocation information according to whether a scheduling release message is included in the scheduling allocation information. If the amount of packet data is greater than or equal to the threshold or if the unscheduling message is not received, the UE returns to step 1702 to continue receiving the scheduling assignment information. On the other hand, if the amount of the packet data is smaller than the threshold or if the unscheduling message is received, go to step 1718. In step 1718, the UE determines whether to continue the uplink packet transmission service. If it is determined that the uplink packet transmission service is to be continued, the UE moves to step 1720, waits until the next scheduling interval, and returns to step 1700. If it is determined that the uplink packet transmission service is to be stopped, the operation ends.
Meanwhile, in the present specification, specific embodiments of the present invention have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

As described above, according to the present invention, when the amount of data waiting in the terminal buffer is greater than or equal to a predetermined threshold, signaling overhead for transmitting uplink packet data by transmitting buffer state and CSI information, which are information necessary for base station control scheduling, in different periods. Can be reduced. Accordingly, it is possible to efficiently use radio resources used in the EUDCH mobile communication system.

Claims (59)

In a mobile communication system supporting an uplink packet data service, a buffer state of a buffer storing packet data to be transmitted by a user terminal for scheduling of the uplink packet data service and a channel state indicating uplink transmission power are determined. In the transmission method, Obtaining a buffer state transmission period and a channel state transmission period, wherein the buffer state transmission period and the channel state transmission period are set differently from each other, Starting transmission of the buffer state and the channel state if the amount of packet data stored in the buffer is greater than or equal to a predetermined threshold; And after transmitting the buffer state and the channel state, periodically transmitting the buffer state and the channel state according to the buffer state transmission period and the channel state transmission period. delete delete The method as claimed in claim 1, wherein the buffer state is transmitted by adding a cyclic redundancy bit for error detection. The method of claim 1, further comprising: stopping the periodic transmission of the buffer state and the channel state when the amount of packet data is smaller than the threshold after starting the periodic transmission of the buffer state and the channel state. The method characterized in that. 2. The method of claim 1, wherein the transmission of the buffer state and the channel state is performed when a message requesting to stop the buffer state and the channel state transmission is received from a base station after the transmission of the buffer state and the channel state. The method further comprises the step of stopping. The method according to claim 1, wherein the buffer state transmission period and the channel state transmission period are determined according to a required quality of service of an uplink packet data service and a radio resource for receiving the uplink packet data service. Way. In a mobile communication system supporting an uplink packet data service, a base station receives a buffer state and a channel state from a user terminal for scheduling of the uplink packet data service, Acquiring a buffer state receiving period and a channel state receiving period, wherein the buffer state receiving period and the channel state receiving period are different from each other; Determining whether a buffer state and a channel state are first received from the user terminal; And when the buffer state and the channel state are first received from the user terminal, periodically receiving the buffer state and the channel state according to the buffer state reception period and the channel state reception period. The method. The method of claim 8, further comprising: estimating a buffer state of the user terminal by using a difference between a previous buffer state and an amount of packet data received after the previous buffer state; And stopping the periodic reception of the buffer state and the channel state when the estimated buffer state is smaller than a predetermined threshold. delete The method as claimed in claim 8, wherein the buffer status reception period is set longer than the channel status information reception period. The method as claimed in claim 8, wherein the channel state information receiving period is set longer than the buffer state receiving period. delete The method of claim 8, wherein the buffer state receiving period and the channel state receiving period, And a required quality of service of an uplink packet data service and a radio resource of the base station for receiving the uplink packet data service. delete 2. The method of claim 1, wherein the buffer state and the channel state are respectively transmitted in allocated transmission regions of a predetermined scheduling interval, and the buffer state transmission period and the channel state transmission period are integer multiples of the scheduling interval length. Said method. The method of claim 1, wherein the buffer state and the channel state are allocated to each of the scheduling intervals separated by an integer multiple of the buffer state transmission period and the channel state transmission period, respectively, immediately after the transmission of the buffer state and the channel state. The method characterized in that the transmission on the transmission area. The buffer state transmission period of claim 1, wherein the buffer state and the channel state are respectively set from the first designated scheduling interval and the first designated scheduling interval, respectively, after the buffer state and the channel state are started. And a plurality of scheduled scheduling intervals separated by an integer multiple of the channel state transmission period. 19. The method as claimed in claim 18, wherein the predetermined scheduling intervals for the buffer state or the channel state are determined according to the following equation.

Herein, CNT _{sch_int} is a section number of the designated scheduling intervals, and the offset is an integer value which is set so as not to overlap with other terminals providing uplink packet data service as much as possible, and mod is an operator for calculating the remainder. Is the buffer state transmission period or the channel state transmission period, and the T _{sch_int} is the scheduling interval length. The method as claimed in claim 1, wherein the buffer state transmission period is set longer than the channel state transmission period. 21. The method as claimed in claim 20, wherein the buffer state transmission period is set longer than the channel state transmission period when the user terminal is in soft handover communicating with at least two base stations. The method as claimed in claim 1, wherein the channel state transmission period is set longer than the buffer state transmission period. The channel state transmission period of claim 1, wherein the channel state transmission period is set longer than the buffer state transmission period when the channel state reflects a change in the uplink channel condition for a period long enough to overcome long period fading. Said method. The method of claim 8, wherein the determining is performed. Obtaining, from the user terminal, received data estimated to include the buffer state and a cyclic redundancy code (CRC) for detecting a transmission error of the received data; And receiving the buffer status and the channel status if there is no error in the received data as a result of checking the CRC. 10. The method of claim 8, wherein the buffer state and the channel state are respectively received in the allocated transmission areas of a predetermined scheduling interval, the buffer state receiving period and the channel state receiving period is an integer multiple of the length of the scheduling interval. Said method. 26. The method of claim 25, wherein the buffer state and the channel state are allocated to each of the scheduling intervals separated by an integer multiple of the buffer state reception period and the channel state reception period, respectively, immediately after the buffer state and the channel state are first received. And the received method is received in the transmission area. 26. The method of claim 25, wherein the buffer state and the channel state are respectively received from the first designated scheduling interval and the first designated scheduling interval after the buffer state and the channel state are first received. And in the allocated transmission area of each of the predetermined scheduling intervals separated by an integer multiple of the channel state reception period. 28. The method as claimed in claim 27, wherein the predetermined scheduling intervals for the buffer state or the channel state are determined according to the following equation.

Herein, CNT _{sch_int} is a section number of the designated scheduling intervals, and the offset is an integer value which is set so as not to overlap with other terminals providing uplink packet data service as much as possible, and mod is an operator for calculating the remainder. Is the buffer state receiving period or the channel state receiving period, and the T _{sch_int} is the scheduling interval length. 10. The method of claim 9, further comprising transmitting a message requesting the suspension of the buffer status and the channel status transmission to the user terminal. 12. The method as claimed in claim 11, wherein the buffer state receiving period is set longer than the channel state receiving period when the user terminal is in soft handover communicating with at least two base stations including the base station. . The channel state reception period of claim 12, wherein the channel state reception period is set longer than the buffer state reception period when the channel state reflects a change in the uplink channel condition for a period long enough to overcome long period fading. Said method. In a mobile communication system supporting an uplink packet data service, a buffer state of a buffer storing packet data to be transmitted by a user terminal and a channel state indicating an uplink transmission power for scheduling of the uplink packet data service In the transmitting apparatus of the user terminal for transmitting the; A transmission start and end determiner for determining a transmission start time and a transmission end time of the buffer state and the channel state by comparing an amount of packet data stored in the buffer with a predetermined threshold value, wherein the transmission start time point is A time point at which the amount of packet data reaches the threshold, A transmission time determiner for acquiring different buffer state transmission periods and channel state transmission periods, and determining a buffer state transmission time and a channel state transmission time according to the buffer state transmission period and the channel state transmission period, respectively, from the transmission start time point; , A buffer state transmitter for periodically transmitting the buffer state at the determined buffer state transmission time point; And a channel state transmitter for periodically transmitting the channel state at the determined channel state transmission point. 33. The method of claim 32, wherein the buffer state transmitter, A switch for receiving the buffer state at the time of transmission of the determined buffer state; A CRC adding unit for adding a cyclic redundancy code (CRC) for detecting a transmission error of the buffer state to the buffer state; And a channel encoder for channel encoding and transmitting the buffer state to which the CRC is added. The method of claim 32, wherein the channel state transmitter, A switch receiving the channel state at the time of transmission of the determined channel state; And a channel encoder for channel encoding the channel state and transmitting the channel state. 33. The method of claim 32, wherein the buffer state and the channel state are respectively carried in the allocated transmission regions of a predetermined scheduling interval, and the buffer state transmission period and the channel state transmission period are integer multiples of the scheduling interval length. The transmitting device. 36. The method of claim 35, wherein the buffer state transmission time and the channel state transmission time, And scheduling periods separated from each other by an integer multiple of the buffer state transmission period and the channel state transmission period, respectively, from the transmission start time point. 36. The method of claim 35, wherein the buffer state transmission time and the channel state transmission time, And each of the predetermined scheduling periods separated from each other by an integer multiple of the buffer state transmission period and the channel state transmission period, respectively, from the first designated scheduling interval and the first designated scheduling interval after the transmission start point. . The apparatus of claim 37, wherein the specified scheduling intervals are determined according to the following equation.

Herein, CNT _{sch_int} is a section number of the designated scheduling intervals, and the offset is an integer value which is set so as not to overlap with other terminals providing uplink packet data service as much as possible, and mod is an operator for calculating the remainder. Is the buffer state transmission period or the channel state transmission period, and the T _{sch_int} is the scheduling interval length. 33. The method of claim 32, wherein the transmission start and end determiner, And the transmission end time is determined when the amount of packet data becomes smaller than the threshold value after the transmission start time. 33. The method of claim 32, wherein the transmission start and end determiner, And a time point at which the message requesting to stop the buffer state and the channel state transmission is received from the base station after the transmission start time point is determined as the transmission end time point. The apparatus of claim 32, wherein the buffer state transmission period is set longer than the channel state transmission period. 42. The apparatus as claimed in claim 41, wherein the buffer state transmission period is set longer than the channel state transmission period when the user terminal is in soft handover communicating with at least two base stations. The apparatus of claim 32, wherein the channel state transmission period is set longer than the buffer state transmission period. 33. The method of claim 32, wherein the channel state transmission period is set longer than the buffer state transmission period when the channel state reflects a change in the uplink channel condition for a period long enough to overcome long period fading. The transmitting device. 33. The method of claim 32, wherein the buffer state transmission period and the channel state transmission period are determined according to a required quality of service of an uplink packet data service and a radio resource for receiving the uplink packet data service. Transmitter. In a mobile communication system supporting an uplink packet data service, the receiving apparatus of the base station receiving a buffer state and a channel state from a user terminal in order for a base station to perform scheduling of the uplink packet data service, Acquiring different buffer state reception periods and channel state reception periods, and receiving buffer state reception time and channel state reception time according to the buffer state reception period and the channel state reception period from the buffer state and the channel state reception start time. A reception time controller for determining each, A buffer state receiver for determining whether the buffer state is first received from the user terminal to determine when the buffer state is first received as the reception start time point, and periodically receiving the buffer state at the determined buffer state reception time point; , And a channel state receiver for periodically receiving the channel state at the time of receiving the determined channel state. The method of claim 46, wherein the buffer state receiver, A switch receiving input data estimated to include the buffer state and a cyclic redundancy code (CRC) of the received data, wherein the switch continuously passes the received data before the start of reception and starts the reception After the time point, the received data is passed through at the time of receiving the determined buffer state, A CRC checker for checking the CRC and outputting the received data if there is no error in the received data; And a channel decoder which detects the buffer state by decoding the received data. The method of claim 46, wherein the channel state receiver, A switch for receiving received data including the channel state at the time of receiving the determined channel state; And a channel decoder which detects the channel state by decoding the received data. 47. The method of claim 46, wherein the buffer state and the channel state are respectively received in the allocated transmission regions of a predetermined scheduling interval, and the buffer state receiving period and the channel state receiving period are integer multiples of the scheduling interval length. The receiving device. The method of claim 49, wherein the buffer state reception time and the channel state reception time, And the allocated transmission area of each of the scheduling intervals separated by an integer multiple of the buffer state reception period and the channel state reception period, respectively, from the reception start time point. The method of claim 49, wherein the buffer state reception time and the channel state reception time, After the reception start time point, each of the predetermined scheduling intervals and the predetermined scheduling intervals separated from the first designated scheduling interval by an integer multiple of the buffer state reception period and the channel state reception period, respectively, are allocated in the allocated transmission area. The receiving device, characterized in that transmitted. 53. The receiver of claim 51, wherein the specified scheduling intervals are determined according to the following equation.

Herein, CNT _{sch_int} is a section number of the designated scheduling intervals, and the offset is an integer value which is set so as not to overlap with other terminals providing uplink packet data service as much as possible, and mod is an operator for calculating the remainder. Is the buffer state receiving period or the channel state receiving period, and the T _{sch_int} is the scheduling interval length. The method of claim 46, wherein the reception time controller, Estimating a buffer state of the user terminal using a difference between a previous buffer state and an amount of packet data received after the previous buffer state, and determining the end point of reception if the estimated buffer state is smaller than a predetermined threshold. The receiving device, characterized in that. 54. The system of claim 53, wherein the reception time controller is: And receiving a message for requesting stopping of the buffer state and the channel state transmission to the user terminal at the reception end time. 47. The apparatus of claim 46, wherein the buffer state reception period is set longer than the channel state reception period. 56. The method of claim 55, wherein the buffer state receiving period is set longer than the channel state receiving period when the user terminal is in soft handover communicating with at least two base stations including the base station. Device. 53. The receiver of claim 51, wherein the channel state reception period is set longer than the buffer state reception period. 58. The method of claim 57, wherein the channel state receiving period is set longer than the buffer state receiving period when the channel state reflects a change in the uplink channel condition for a period long enough to overcome long term fading. The receiving device. 53. The method of claim 51, wherein the buffer state receiving period and the channel state receiving period, And the radio frequency of the base station is determined according to a required quality of service of an uplink packet data service and a radio resource of the base station for receiving the uplink packet data service.

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