JP2005184099A - Mobile station, mobile communication system, and base station thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile station that reliably transmits high-speed data from a base station to the mobile station by increasing reliability in incoming information to the base station from the mobile station and can improve throughput in the high-speed transmission, and to provide a mobile communication system and the base station thereof. <P>SOLUTION: The mobile station comprises a base station selector 19 for calculating a received power parameter 18a from the base station in an active set, and determining a primary base station in the base stations in active set; a transmission processor 23 for transmitting an ID19a of the primary base station to the base station in active set by an incoming control channel; a power control command extractor 20 for extracting a power control command 20a from the base station in active set; and a transmission power control unit 22 for controlling the transmission power of the control information by the power control command from the base station selected as the primary base station. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a mobile station, a mobile communication system, and a base station of the system capable of improving the reliability of communication of control information, and more particularly to a third generation mobile communication system.

  In 3GPP (3rd Generation Partnership Project), which is a standardization organization of IMT-2000 (International Mobile Telecommunications-2000), a high-speed downlink packet transmission method (HSPDA: High-speed downlink Packets Acknowledgment) 1).

  The high-speed downlink packet transmission system (HSPDA) has a maximum transmission speed of 10 Mbps or more in order to realize high-speed communication such as downloading of a moving image from a base station to a mobile station and a streaming service.

  In addition, there is a cellular system that has been studied to further improve 3GPP (see, for example, Patent Document 1). In the cellular system of Patent Document 1, prior to performing high-speed packet transmission from the base station to the mobile station, each base station in the active set is in the sequence period for selecting the primary base station. An offset is added to the desired SIR (ratio of received signal power to interference signal power).

As a result, the mobile station can increase the transmission power of the uplink control channel more than in the case of 3GPP only during the period during which this downlink high-speed packet transmission is performed. As a result, the active set base station can receive the primary base station ID transmitted from the mobile station via the uplink control channel without error.
Published by 3GPP “Technical Specification TR25.848v4.0.0” March 2001 JP 2002-325063 A (page 9-12, FIG. 1 to FIG. 6)

  By the way, in the prior art system described in Non-Patent Document 1 described above, at least one active set base station guarantees that control information can be received without error from a mobile station via an uplink control channel. . Therefore, the primary base station does not always correspond to “at least one active set base station”. The primary base station does not guarantee that the primary base station ID from the mobile station can be received without error. Further, it is not guaranteed that the primary base station ID from the mobile station can be received without error in all the base stations in the active set.

  As a result, the active set base station recognizes that the primary base station has not been selected and stops downlink high-speed packet transmission, resulting in a problem that throughput decreases. Alternatively, there are problems that a plurality of active set base stations recognize that they are selected as primary base stations and start downlink high-speed packet transmission, resulting in increased interference and reduced channel utilization efficiency in the mobile station.

  Further, in the above-described prior art system of Patent Document 1, the reliability of information communication using the uplink control channel from the mobile station to the base station is not the same as that of Non-Patent Document 1 described above, except during the sequence period in which the primary base station is selected. It is the same. As a result, the active set base station erroneously recognizes information communication other than the primary base station ID as information communication of the primary base station ID and starts downlink high-speed packet transmission, increasing interference in the mobile station and channel utilization. There is a problem that efficiency decreases.

  The present invention has been made to solve the above-described problems, and by improving the reliability of uplink control information from the mobile station to the base station, data transmission from the base station to the mobile station is ensured. An object of the present invention is to provide a mobile station, a mobile communication system, and a base station of the same system that can be performed and can improve the throughput of data transmission.

  In order to achieve the above object, the mobile station of the present invention is selected by a base station selection unit that selects a primary base station that is a data transmission source from a plurality of base stations in an active set, and the base station selection unit. A transmission means for transmitting a primary base station ID indicating the primary base station to a plurality of base stations of the active set with a predetermined transmission power by an uplink control channel; and a plurality of base stations transmitted from the plurality of base stations of the active set A receiving means for receiving a power control command signal and a data signal transmitted from a base station selected as the primary base station; and the primary base station among the plurality of power control command signals received by the receiving means. The primary base station I by the power control command signal from the base station selected as Characterized by comprising a transmission power controlling means for controlling the transmission power of the uplink control channel during transmission.

  The mobile station of the present invention includes: a base station selection unit that selects a primary base station that is a data transmission source from a plurality of base stations in an active set; and the primary base station that is selected by the base station selection unit. A transmitting means for transmitting the indicated primary base station ID to a plurality of base stations of the active set with a predetermined transmission power using an uplink control channel, a plurality of power control command signals transmitted from the plurality of base stations of the active set, and Receiving means for receiving a data signal transmitted from a base station selected as a primary base station, and when changing the primary base station, the changed primary base station ID is transmitted from a predetermined time before the changed primary base station ID transmission. In response to the power control command signal from the base station selected as the base station, the uplink control channel Characterized by comprising a transmission power controlling means for controlling the transmission power of.

  The mobile station of the present invention includes: a base station selection unit that selects a primary base station that is a data transmission source from a plurality of base stations in an active set; and the primary base station that is selected by the base station selection unit. A transmitting means for transmitting the indicated primary base station ID to a plurality of base stations of the active set with a predetermined transmission power using an uplink control channel, a plurality of power control command signals transmitted from the plurality of base stations of the active set, and A receiving means for receiving a data signal transmitted from a base station selected as a primary base station, and a ratio of commands for requesting power increase from the plurality of power control command signals received within a predetermined period by the receiving means Calculate for each of a plurality of base stations, and determine the uplink propagation environment quality of the uplink control channel based on the ratio And when the primary base station is changed, the uplink propagation environment quality of the base station selected as the primary base station after the change based on the uplink propagation environment determination means is When the uplink propagation environment quality of the base station selected as the primary base station is worse than the predetermined time before the changed primary base station ID transmission, from the base station selected as the changed primary base station Transmission power control means for controlling the transmission power of the uplink control channel by a power control command signal.

  According to the present invention, by improving the reliability of uplink control information from the mobile station to the base station, high-speed data transmission from the base station to the mobile station is reliably performed, and the throughput of high-speed data transmission is improved. It becomes possible.

Embodiments of the present invention will be described below with reference to the drawings.
1 to 9 show an embodiment in which the present invention is applied to a mobile communication system, FIG. 1 is a configuration diagram of the mobile communication system, FIG. 2 is a block diagram showing a configuration of a main part of the mobile station, and FIG. It is a block diagram which shows the structure of the principal part of a station. 4 to 8 are sequence diagrams illustrating transmission power control in the first to fourth embodiments, and FIG. 9 is a flowchart illustrating the operation of the base station in the fifth embodiment.

  FIG. 1 shows a configuration diagram of an example of a mobile communication system in a handover state. A mobile station 4 such as a mobile phone measures the received power of a common pilot signal transmitted from the base station 1, the base station 2, the base station 3, and another base station (not shown). In FIG. 1, it is assumed that the mobile station 4 is in a handover state, for example, between the base station 1, the base station 2, the base station 3, and the mobile station 4 that is equal to or greater than a predetermined threshold. The base station in the handover state is referred to as an active set. In this example, the base station 1, the base station 2, and the base station 3 are active sets. A base station that performs high-speed downlink data transmission to the mobile station 4 among the plurality of active set base stations 1 to 3 is referred to as a primary base station. This primary base station is determined by the judgment of the mobile station 4.

  In the mobile communication system shown in FIG. 1, there are four communication channels as communication channels between the mobile station 4 and the base stations 1 to 3. That is, the downlink high-speed shared channels 1a, 2a and 3a, the downlink common pilot channels 1b, 2b and 3b, and the downlink dedicated channels 1c, 2c and 3c are communication channels for transmitting data from the base stations 1 to 3 to the mobile station 4. The uplink control channel 4a is a communication channel for transmitting data from the mobile station 4 to the base stations 1 to 3.

  The downlink high-speed shared channels 1a, 2a and 3a are used when high-speed packet transmission of data transmission from the base stations 1 to 3 to the mobile station 4 is performed. The downlink common pilot channels 1 b, 2 b and 3 b are used when transmitting a common pilot signal from the base stations 1 to 3 to the mobile station 4. Then, the mobile station 4 measures the reception power of the common pilot signal and determines the downlink propagation environment quality. The downlink dedicated channels 1c, 2c, and 3c are used when a power control command that instructs increase / decrease of transmission power of the mobile station is transmitted from the base stations 1 to 3 to the mobile station 4.

  On the other hand, the frame structure of the uplink control channel 4a, which is a communication channel for transmitting data from the mobile station 4 to the base stations 1 to 3, is composed of individual pilot signals, control data frames, and the like. Based on this individual pilot signal, the base stations 1 to 3 measure the received power from the mobile station 4. Based on the control data frame, the base stations 1 to 3 receive the primary base station ID determined by the mobile station 4 and other control information.

  FIG. 2 is a block diagram showing the configuration of the main part of the mobile station 4. The main part of the mobile station 4 includes an antenna 11, a radio processing unit 12, a synchronization processing unit 13, a signal processing unit 14, a separation processing unit 15, a decoding processing unit 16, a received data control unit 17, a received power measuring unit 18, and a base station. A selection unit 19, a power control command extraction unit 20, a transmission data control unit 21, a transmission power control unit 22, a transmission processing unit 23, and the like are included.

  Next, functions of each unit of the mobile station 4 will be described. Radio signals transmitted from the base stations 1 to 3 are received by the antenna 11 and transmitted to the radio processing unit 12. The wireless processing unit 12 performs wireless processing such as down-conversion and A / D conversion on the received wireless signal, and sends the converted signal to the synchronization processing unit 13 and the signal processing unit 14.

  The synchronization processing unit 13 extracts a synchronization signal from the converted radio signal, and sends an optimal reception timing signal to the signal processing unit 14. The signal processing unit 14 performs signal processing such as transmission path compensation and demodulation processing on the converted radio signal using the reception timing output from the synchronization processing unit 13. The separation processing unit 15 extracts a data signal 15a using a downlink high-speed shared channel, a common pilot signal 15b using a downlink common pilot channel, and a control signal 15c using a downlink dedicated channel from the radio signal subjected to signal processing by the signal processing unit 14. To do.

  When receiving the data signal 15 a output from the separation processing unit 15, the decoding processing unit 16 performs decoding processing such as turbo decoding or Viterbi decoding, and sends the decoded data 16 a to the reception data control unit 17. The reception data control unit 17 performs processing according to the content of the decoded data 16a.

  When the received power measuring unit 18 receives the common pilot signal 15b output from the separation processing unit 15, the received power measuring unit 18 calculates received power parameters 18a such as received power, received SIR (received signal power to interference signal power ratio), and propagation loss. Then, the calculation result is sent to the base station selection unit 19.

  When the base station selection unit 19 receives the reception power parameter 18a output from the reception power measurement unit 18, the base station selection unit 19 determines to extract the best base station in the downlink propagation environment. As this determination method, for example, a method in which the received power is larger is the best base station, a method in which the received SIR is larger is the best base station, and a method in which the propagation loss is smaller is the best base station. Any method such as the method described above may be used. Furthermore, the best base station may be extracted by combining a plurality of these determinations. The base station selection unit 19 determines the extracted base station with the best downlink propagation environment as a primary base station that performs high-speed downlink data transmission.

  Then, the base station selection unit 19 sends the ID for identifying the determined primary base station to the transmission power control unit 22 and the transmission data control unit 21 as the primary base station ID 19a.

  When receiving the control signal 15 c output from the separation processing unit 15, the power control command extraction unit 20 extracts the power control command 20 a from all base stations in the active set and sends it to the transmission power control unit 22.

  The transmission data control unit 21 sends transmission data 21b created in the mobile station 4 and transmitted to all base stations of the active set to the transmission processing unit 23. The transmission data 21b includes control information such as a primary base station ID indicating the primary base station and other ACK signals. In addition, the transmission data control unit 21 transmits to the transmission power control unit 22 an ID transmission timing 21a indicating the timing at which the primary base station ID is transmitted to all base stations in the active set.

  When the transmission processing unit 23 receives the transmission data 21b output from the transmission data control unit 21, the transmission processing unit 23 performs signal processing such as encoding processing such as turbo encoding and convolutional encoding and modulation processing, and the transmission generated thereby. The signal 23a is sent to the wireless processing unit 12.

  When the wireless processing unit 12 receives the transmission signal 23 a output from the transmission processing unit 23, the wireless processing unit 12 performs wireless processing such as D / A conversion and up-conversion, generates a wireless signal, and transmits the wireless signal to the antenna 11. The antenna 11 transmits the radio signal to all base stations in the active set via the uplink control channel 4a.

  The transmission power control unit 22 includes a primary base station ID 19 a output from the base station selection unit 19, a power control command 20 a from all active set base stations output from the power control command extraction unit 20, and a transmission data control unit 21. When the ID transmission timing 21 a output from is received, the transmission power signal 22 a is transmitted to the wireless processing unit 12. The radio processing unit 12 performs the same radio processing as described above, and transmits a radio signal generated thereby from the antenna 11 to all base stations of the active set via the uplink control channel 4a.

  Note that the configuration of the mobile station 4 is not limited to the above-described block unit. For example, the reception power measurement unit 18 and the base station selection unit 19 may be in the same block. Further, the power control command extraction unit 20 and the transmission power control unit 22 may be in the same block. As for the combination, the hardware configuration may be arbitrarily designed along the signal flow.

  FIG. 3 is a block diagram of main parts applied to the base stations 1 to 3. The main part of the base station includes an antenna 51, a radio processing unit 52, a reception processing unit 60, a reception data control unit 53, a user management unit 54, a transmission data control unit 55, a transmission processing unit 56, and the like.

  Among these, the reception processing units 60 are provided by the number of mobile stations that the base station is to communicate with. The reception processing unit 60 includes a synchronization processing unit 61, a signal processing unit 62, a separation processing unit 63, a decoding processing unit 64, a primary base station ID extraction unit 65, a received power measurement unit 66, a power control command generation unit 67, and the like. Is done.

  A radio signal from the mobile station 4 is received by the antenna 51 and transmitted to the radio processing unit 52. The wireless processing unit 52 performs wireless processing such as down-conversion and A / D conversion on the received wireless signal, and sends it to the synchronization processing unit 61 and the signal processing unit 62.

  The synchronization processing unit 61 performs timing synchronization and sends the optimal reception timing to the signal processing unit 62. The signal processing unit 62 performs signal processing such as transmission path compensation and demodulation processing using the reception timing from the synchronization processing unit 61. The separation processing unit 63 extracts the data signal 63a, the control signal 63b, and the dedicated pilot signal 63c based on the uplink control channel from the input signal subjected to the signal processing from the signal processing unit 62.

  The decoding processing unit 64 performs decoding processing such as turbo decoding or Viterbi decoding on the data signal 63 a from the separation processing unit 63, and sends the generated decoded data 64 a to the reception data control unit 53. The reception data control unit 53 performs processing according to the content of the decoded data 64a.

  The primary base station ID extraction unit 65 extracts the primary base station ID from the control signal 63 b from the separation processing unit 63 and sends the extracted primary base station ID 65 a to the user management unit 54. Also, control signals such as ACK signals are extracted.

  The received power measuring unit 66 measures received power parameters such as received power, received SIR, and propagation loss from the dedicated pilot signal 63c from the separation processing unit 63, and uses the measured received power parameter 66a as a power control command generating unit 67 and The data is sent to the user management unit 54.

  The power control command generation unit 67 generates a power control command 67a by comparing the preset desired SIR desired by the own station with the reception SIR of the mobile station 4 measured by the reception power measurement unit 66. The data is sent to the user management unit 54 and the transmission processing unit 56.

  The content of the power control command 67a is that when the received SIR of the mobile station 4 measured by the received power measuring unit 66 is larger than the desired SIR in the own station, the power control command “0” for reducing the transmission power of the mobile station 4 is obtained. ”Is generated, and when the received SIR of the mobile station 4 is smaller than the desired SIR in the own station, a power control command“ 1 ”for increasing the transmission power of the mobile station 4 is generated.

  The user management unit 54 includes a primary base station ID 65a from the primary base station ID extraction unit 65, a reception SIR included in the reception power parameter 66a from the reception power measurement unit 66, and a power control command 67a from the power control command generation unit 67. From this, it is determined whether the own station is selected as a primary base station from the mobile station 4.

  When it is determined that the transmission data control unit 55 is selected as the primary base station, the transmission data control unit 55 sends the transmission data 55 a to be transmitted to the mobile station 4 to the transmission processing unit 56. The transmission processing unit 56 performs coding processing such as turbo coding and convolutional coding on the transmission data 55 a from the transmission data control unit 55, further performs signal processing such as modulation processing, and sends the data to the wireless processing unit 52. To do.

  The wireless processing unit 52 performs wireless processing such as D / A conversion and up-conversion on the transmission signal 56 a from the transmission processing unit 56 and sends the wireless signal to the antenna 51. The antenna 51 transmits a radio signal to the mobile station 4 using the downlink high-speed shared channel.

  In addition, the transmission processing unit 56 performs signal processing such as modulation processing on the power control command 67 a from the power control command generation unit 67 and sends the signal processing to the wireless processing unit 52. The wireless processing unit 52 performs wireless processing such as D / A conversion and up-conversion on the power control command, and sends the wireless signal to the antenna 51. The antenna 51 transmits a radio signal of a power control command to the mobile station 4 using the downlink dedicated channel.

  Note that the configuration of the base station is not limited to the above-described block unit. For example, adjacent blocks along the signal flow may be the same block, and the combination depends on the ease of hardware configuration. You may configure.

Next, the operation of the first embodiment of the mobile communication system will be described with reference to FIGS.
FIG. 4 is a sequence illustrating transmission power control in the first embodiment. Note that the sequence in FIG. 4 proceeds along the time axis from right to left.

  The period of the timings Tb1, Tb2, and Tb3 is Tb, which is the minimum basic timing of base station selection control. The period of the timings T1a to T8a, T1 to T8, and T9 to T16 is Tp, which is the minimum basic timing for transmission power control. In 3GPP, it is defined that the period Tb is selected from 3 times, 4 times, 5 times, 8 times, and 15 times the period Tp. In this example, the period Tb will be described below as 8 times.

  The mobile station 4 measures the reception quality in the downlink propagation environment of the common pilot signals from the base stations 1 to 3 at the timing Tb1, and determines the base station having the best reception quality, for example, the base station 1, as the primary base station ( Sequence S1). This measurement does not need to use all the sections of the timings T1a to T8a in the timing Tb1, but the accuracy is improved by measuring as long as possible.

  The primary base station determination method may be base station selection based on resources owned by the base station.

  Then, the mobile station 4 transmits the ID of the determined base station 1 as the primary base station to the base stations 1 to 3 at all timings T1 to T8 within the next timing Tb2 (sequence S2). In 3GPP, it is defined that the determined primary base station ID is transmitted at all Tp timings in Tb (timing T1 to T8 in the case of timing Tb1).

  The primary base station ID is transmitted to the base stations 1 to 3 after transmission power control is performed as a transmission signal of the uplink control channel. Then, the base stations 1 to 3 that have received this are compared with the desired reception SIR of each base station, and the TPC (transmission) instructing increase / decrease in the transmission power of the transmission signal of the uplink control channel so that the desired reception SIR is obtained. A power control command) is transmitted to the mobile station 4. This is closed-loop power control performed in a Tp cycle, and this is repeated in a Tp cycle.

  In the first embodiment of the present invention, the mobile station 4 transmits the TPC (transmission power control command) of the Tp cycle transmitted from the primary base station at all timings T1 to T8 within the timing Tb2 for transmitting the primary base station ID. ), The transmission power of the transmission signal of the primary base station ID is controlled and transmitted to the base stations 1 to 3.

  Accordingly, within the timing Tb2, the mobile station 4 includes “1 (up)” or “0” of the TPCs of T1 to T8 illustrated by hatching among the TPCs (reference numeral 31) from the base station 1 that is the primary base station. Down) ", the transmission power of the transmission signal of the ID of the base station 1 is increased / decreased by a predetermined unit power like P1 to P8 and transmitted to the base stations 1 to 3.

  As a result, during the period in which the primary base station ID is transmitted, power control is performed from the primary base station having the base station ID, so that at least the primary base station can receive the primary base station ID without error.

  The base station 1 that is the primary base station among the base stations 1 to 3 that has received the primary base station ID at the timing Tb2 performs high-speed downlink data transmission to the mobile station 4 at the next timing Tb3 (sequence S3).

  The channel used for the high-speed downlink data transmission is not limited to the downlink high-speed shared channel 1a, and may be transmitted using the downlink dedicated channel 1c when the amount of data is small.

  The relationship between the above sequences S1, S2, and S3 is performed after shifting by the period Tb. That is, it is assumed that the reception quality in the downlink propagation environment is measured at timing Tb2, and for example, the same base station 1 as that at timing Tb1 is determined as the primary base station (sequence S1).

  Then, at the timing Tb3, the ID of the base station 1 that is the primary base station determined at the timing Tb2 is transmitted (sequence S2). Similarly, in this transmission, among the TPCs (reference numeral 31) from the base station 1, which is the primary base station, the TPCs T9 to T16 illustrated by hatching indicate “1 (up)” or “0 (down)”. Therefore, the transmission power of the transmission signal of the ID of the base station 1 is controlled as P9 to P12,... P16 (not shown) and transmitted to the base stations 1 to 3.

  The base station 1 which is the primary base station among the base stations 1 to 3 having received the primary base station ID at the timing Tb3 performs high-speed downlink data transmission to the mobile station 4 at the next timing Tb4 (not shown) ( Sequence S3). Thereafter, the shift is continued by the period Tb.

  The transmission power control in the mobile station 4 described above is represented by reference numeral 34. As a result of selecting the base station 1 as the primary base station, the bit shown in the hatching of the TPC (reference numeral 31) from the base station 1 becomes the transmission power control bit (reference numeral 34) in the mobile station 4, and based on this Transmission power control is performed. TPC (reference numeral 32) from the base station 2 and TPC (reference numeral 33) from the base station 3 are ignored.

  As described above, according to the first embodiment, the mobile station 4 increases the transmission power of the uplink control channel 4a according to the power control command from the base station selected as the primary base station among the active set base stations 1 to 3. Control. Thereby, the base station selected as the primary base station can receive the primary base station ID transmitted by the uplink control channel 4a without error. Therefore, the mobile station 4 ensures a state in which communication with the primary base station can be reliably performed, and communication reliability can be improved.

A second embodiment of the mobile communication system to which the present invention is applied will be described with reference to FIG.
FIG. 5 is a sequence showing transmission power control of the mobile communication system in the second embodiment. In addition, the system configuration, the configuration of the mobile station 4, and the configurations of the base stations 1 to 3 in the second embodiment are the same as those shown in FIGS. The same parts as those in FIG. 4 are given the same reference numerals, and the system configuration, the configuration of the mobile station 4, and the configurations of the base stations 1 to 3 will be described with reference to FIGS.

  The mobile station 4 measures the reception quality of the common pilot signal from the base stations 1 to 3 in the downlink propagation environment, and determines the base station with the best reception quality as the primary base station. As a primary base station, it is assumed that base station 1 is determined at timing Tb1 (sequence S1), and that it is determined to change to base station 2 at timing Tb2 (sequence S11). Note that the primary base station is determined at an early stage within the period Tb, for example, at timing Tb2 by timing T5.

  In this case, the mobile station 4 transmits the base station 1ID to the base stations 1 to 3 at the timing Tb2 corresponding to each primary base station determination (sequence S2), and the base station changed from the base station 1 2ID is transmitted to base stations 1 to 3 at timing Tb3 which is the next timing (sequence S12).

  Transmission power control at this time is performed as follows. The transmission power control of the base station 1 ID at the timing Tb2 is performed by “1 (up)” or “0 (down) of TPCs of T1 to T5 illustrated by solid line hatching among TPCs (reference numeral 31) from the base station 1. In accordance with the instruction, the transmission power of the transmission signal with the ID of the base station 1 is controlled as P1 to P5 and transmitted to the base stations 1 to 3.

  At time T5, it is determined that the next primary base station will be changed to the base station 2. In this case, prior to the transmission of the base station 2ID at the timing Tb3 (sequence S12), the transmission power control (sequence S2) of the base station 1ID at the timing T6 to T8 that is earlier by the offset of the period Tp3 is to be changed next time. The transmission signal of the ID of the base station 1 in accordance with the “1 (up)” or “0 (down)” instruction of the TPC of T6 to T8 illustrated by dotted hatching among the TPC (reference numeral 32) from the base station 2 Is transmitted to the base stations 1 to 3 while controlling the transmission power of P60 to P80.

  As a result, since the power control from the base station 2 is followed by the offset, the base station 2 reaches the desired transmission power early. Then, at the time of transmission of the base station 2ID at the timing Tb3 (sequence S12), the base station 2 can reliably receive the base station 2ID without error.

  At the timing Tb2, the transmission power control of the transmission of the base station 1ID (sequence S2) is performed in accordance with the TPC from the unintended base station 2 at the later timings T6 to T8. However, in general, the primary base station does not frequently switch in the cycle Tb, and at the timing Tb1 or the timing before that, the base station 1 is highly likely to be selected as the primary base station. For this reason, there is a high possibility that the transmission power of the base station 1ID continuously reaches the value desired by the base station 1.

  Therefore, even if transmission power control is performed according to TPC from the unintended base station 2 at the last timing T6 to T8, the transmission power desired by the base station 1 is not greatly changed. Therefore, at the timing Tb2, the base station 1 can receive the base station 1ID without error with respect to the transmission of the base station 1ID (sequence S2).

  The transmission power control in the mobile station 4 described above is represented by reference numeral 34. The bit illustrated by the solid line hatching of the TPC (reference numeral 31) from the base station 1 and the bit illustrated by the dotted line hatching of the TPC (reference numeral 32) from the base station 2 are the transmission power control bits ( The transmission power control is performed.

  According to the second embodiment, at the timing of receiving the next primary base station ID, the SIR is close to the desired SIR of the next primary base station with a margin, and the primary base station ID is surely the primary base station ID. Can be received. Accordingly, the mobile station ensures a communicable state with the primary base station, and communication reliability can be improved.

  A third embodiment of the mobile communication system to which the present invention is applied will be described with reference to FIGS. 6 and 7 are sequences showing transmission power control of the mobile communication system according to the third embodiment. FIG. 6 shows a case where the uplink propagation environment quality is poor, and FIG. 7 shows that the uplink propagation environment quality is good. The case of switching to a base station is shown. 6 and 7, the time advances on the time axis from right to left in order to explain the power control sequence.

  With reference to FIG. 6, the case of switching to a base station with poor upstream propagation environment quality will be described below. The same components as those in FIG. 5 are given the same reference numerals, and the system configuration, the configuration of the mobile station 4, and the configurations of the base stations 1 to 3 are different from the second embodiment with reference to FIGS. Mainly explained.

  The mobile station 4 measures the reception quality of the common pilot signal from the base stations 1 to 3 in the downlink propagation environment, and determines the base station with the best reception quality as the primary base station. As a primary base station, it is assumed that base station 1 is determined at timing Tb1 (sequence S1), and that it is determined to change to base station 2 at timing Tb2 (sequence S11). Note that the primary base station is determined at an early stage within the period Tb, for example, at timing Tb2, by timing T5.

  By the way, for the transmission of the primary base station ID, the uplink control channel of the mobile station is used. In this case, the uplink propagation environment for the base station having the best downlink propagation environment is not always the best. The station ID cannot be reliably transmitted to the primary base station.

  Therefore, in the third embodiment, the mobile station 4 estimates the uplink propagation environment to the base stations 1 to 3, and also refers to it to perform the transmission power control of the uplink control channel 4a to ensure the primary base station ID. It is transmitted to the primary base station.

  First, the mobile station 4 estimates the uplink propagation environment to the base stations 1 to 3. This estimation is performed using a power control command (TPC) within a predetermined period from the base stations 1 to 3. This means that when the power control command “1” is transmitted from the base station, an increase in transmission power is requested from the base station, that is, the uplink propagation environment is poor. Therefore, it can be determined that the higher the ratio (hereinafter referred to as the Up rate) of the power control command “1” within the predetermined period, the worse the uplink propagation environment, and the lower the Up rate, the better the uplink propagation environment. .

  Therefore, the mobile station 4 receives the power control commands (reference numerals 31 to 33 in FIG. 6) from the base stations 1 to 3 in the period of the timing T1 to T5 if the timing is the first half of the period Tb, for example, the timing Tb2. Then, the Up rate of the base stations 1 to 3 is calculated. The Up rate of the base station 1 at the timings T1 to T5 is 2/5 because the power control command 31 is “0”, “0”, “1”, “1”, “0”, and the number of “1” is two. Pieces = 0.4. Further, the Up rate of the base station 2 at the timings T1 to T5 is 3/5 = 0.6 from the power control command 32. Further, the Up rate of the base station 3 at the timings T1 to T5 is 4/5 = 0.8 by the power control command 33.

  At time T5, it is determined that the next primary base station will be changed from the base station 1 to the base station 2. Further, at timing T5, the base station 1 = 0.4 and the base station 2 = 0.6 are estimated as the uplink propagation environment to the primary base station. That is, at timing Tb3, base station 2ID is transmitted in the uplink propagation environment of base station 2 = 0.6 which is worse than base station 1 = 0.4 (sequence S12).

  In this case, prior to the transmission of the base station 2ID at the timing Tb3 (sequence S12), the transmission power control (sequence S2) of the base station 1ID at the timing T6 to T8 that is earlier by the offset is performed from the base station 2 to be changed next time. The transmission power of the transmission signal of the ID of the base station 1 is set to P60 in accordance with the “1 (up)” or “0 (down)” instruction of the TPCs of T6 to T8 illustrated by dotted line hatching in the TPC (reference numeral 32) of P60. Control is performed as in P80 and transmitted to the base stations 1 to 3.

  As a result, the power control from the base station 2 with relatively poor uplink propagation environment is followed ahead by the offset, so that the base station 2 reaches the desired transmission power early. Then, at the time of transmission of the base station 2ID at the timing Tb3 (sequence S12), the base station 2 can reliably receive the base station 2ID without error.

With reference to FIG. 7, a case where switching to a base station with relatively good uplink propagation environment quality is described below.
The mobile station 4 measures the reception quality of the common pilot signal from the base stations 1 to 3 in the downlink propagation environment, and determines the base station with the best reception quality as the primary base station. As a primary base station, it is assumed that the base station 3 is determined at the timing Tb1 (sequence S1) and is changed to the base station 1 at the timing Tb2 (sequence S11). Note that the primary base station is determined at an early stage within the period Tb, for example, at timing Tb2 by timing T5.

  At timing T5, it is determined that the primary base station is changed from the current base station 3 to the base station 1 next time. Further, at the timing T5, the base station 3 = 0.8 and the base station 1 = 0.4 are estimated as the uplink propagation environment to the primary base station. That is, at the timing Tb3, the base station 1ID is transmitted in the uplink propagation environment of the base station 1 = 0.4 which is better than the base station 3 = 0.8 (sequence S12).

  In this case, the transmission of the base station 1ID at the timing Tb3 (sequence S12) does not perform transmission power control ahead of the offset, and the TPC (reference numeral 31) from the base station 1 after the timing T9 of the timing Tb3. In accordance with the TPC “1 (up)” or “0 (down)” instruction at timings T9 to T16 illustrated by dotted line hatching, the transmission power of the transmission signal of the ID of the base station 1 is set to P9 to P12,. (Not shown) and transmitted to the base stations 1 to 3.

  Thus, even if it is not precedent by the offset, the uplink transmission to the base station 1 is relatively good in the uplink propagation environment. Therefore, at the time of transmission of the base station 1 ID at the timing Tb3 (sequence S12), the base station 1 The base station 1ID can be reliably received without error.

  According to the third embodiment, the mobile station can estimate the uplink propagation environment to the base station, and can change the transmission power control method based on the estimation result. Thereby, primary base station ID can be reliably transmitted to a primary base station. Accordingly, the mobile station ensures a communicable state with the primary base station, and communication reliability can be improved.

A fourth embodiment of the mobile communication system to which the present invention is applied will be described with reference to FIG.
FIG. 8 shows a sequence showing transmission power control of the mobile communication system in the fourth embodiment. In FIG. 8 as well, the time axis advances from right to left in order to explain the power control sequence.

  Hereinafter, the differences from the third embodiment will be described. 6 and 7 are assigned the same reference numerals, and the system configuration, the configuration of the mobile station 4, and the configurations of the base stations 1 to 3 will be described with reference to FIGS.

  In a mobile communication system, there is a control signal that must guarantee that the mobile station 4 can reliably transmit to all base stations in the active set using the uplink control channel 4a. For example, when downlink high-speed data transmission from the primary base station to the mobile station 4 is transmitted, it is necessary to return an ACK signal (acknowledgment response information) from the mobile station 4 to all the active set base stations in response to the transmission. This ACK signal must be reliably transmitted from the mobile station 4 to all base stations in the active set.

  This is because the primary base station is constantly switched over time, and the base station other than the primary base station needs to grasp the situation of the downlink high-speed data transmission. If the transmission of the ACK signal is not performed reliably, the situation confirmation sequence is newly increased between the mobile station 4 and all base stations in the active set in order to grasp the situation of the downlink high-speed data transmission. It will end up.

  In the fourth embodiment, it is assumed that the mobile station 4 determines the transmission of the ACK signal for the downlink high-speed data transmission at the timing T5 within the timing Tb2 (sequence S11). Then, the mobile station 4 transmits an ACK signal to all base stations in the active set at timings T9 and T10 of the timing Tb3 (sequence S12).

  In this case, prior to the transmission of the ACK signal at the timing Tb3 (sequence S12), the transmission power control (sequence S2) of the base station 1ID at the timing T6 to T8 that is earlier by the offset is performed in the worst base station 3 in the uplink propagation environment. The transmission power of the transmission signal of the ID of the base station 1 in accordance with the “1 (up)” or “0 (down)” instruction of the TPC of T6 to T8 illustrated by dotted line hatching in the TPC (reference numeral 33) from Control is performed as in P60 to P80 and transmitted to the base stations 1 to 3.

  As a result, the power control from the base station 3 having the worst uplink propagation environment is followed by the offset, so that the base station 3 having the worst uplink propagation environment reaches the desired transmission power early. This sufficiently and sufficiently satisfies the transmission power desired by another base station having a better uplink propagation environment than the base station 3. Therefore, at the time of transmission of the ACK signal at timing T9 and timing T10 (sequence S12), all base stations can reliably receive the ACK signal without error.

  After the timing T11 after the transmission of the ACK signal, the TPC (reference numeral 31) from the base station 1 as the primary base station is again “1 (up)” or “ In accordance with the “0 (down)” instruction, transmission power control of the uplink control channel is performed.

  According to the fourth embodiment, it is possible to guarantee the uplink propagation environment to all the base stations 1 to 3 in the active set by guaranteeing the uplink propagation environment to the worst base station in the uplink propagation environment. Therefore, transmission of the ACK signal from the mobile station 4 to all the active set base stations 1 to 3 can be ensured.

  The control of the fourth embodiment is not limited to the ACK signal, but can be applied to transmission of system essential information that should be reliably transmitted to all the base stations 1 to 3.

The base station of the mobile communication system according to the present invention will be described with reference to FIG.
FIG. 9 is a flowchart showing an operation in which the base station determines whether or not the base station is a primary base station.

  As a first determination (step S51), the base station receives primary base station IDs transmitted from the mobile station 4 at the cycle Tp, and compares the eight primary base station IDs within the cycle Tb with its own station ID. To do. Then, it confirms whether or not the own station is selected as the primary base station from the mobile station 4 (steps S52 and S53). This may be a majority decision out of eight.

  If it coincides with its own station ID, it is assumed that the primary base station is selected (YES (“correct”) in step S53)), and if it does not coincide, it is not selected as the primary base station (NO in step S53 (“No” ")).

  If step S53 is YES (“correct”), the process proceeds to the second determination (step S61). On the other hand, when step S53 is NO (“No”), the average value of the received SIRs within the period Tb of the primary base station ID is further calculated from the received SIR of the uplink control channel 4a, and a predetermined threshold value set in advance is calculated. (Step S54). If the calculated average value of received SIRs is smaller than a predetermined threshold value (small in step S54), it means that the line quality of the uplink control channel 4a is poor. Therefore, the base station determines that there is a possibility that the primary base station ID received from the mobile station 4 using this uplink control channel 4a is wrong, and proceeds to the second determination (step S61).

  When the average value of the reception SIR is larger than the predetermined threshold (large in step S54), it means that the line quality of the uplink control channel 4a is good. Therefore, the base station determines that the primary base station ID received from the mobile station 4 using the uplink control channel 4a is correct and makes a final determination that it does not match the own station (step S66).

  Next, the process proceeds to the second determination (step S61). The mobile station 4 shown in the first to fourth embodiments performs transmission power control according to a TPC (power control command) from the primary base station. In this case, at the primary base station, the desired SIR is reached, and the TPC of the primary base station is not biased toward the increase instruction “1 (up)” or the decrease instruction “0 (down)”.

  On the other hand, in a base station that is not selected as a primary base station, the mobile station does not follow the TPC of the own station, so the desired SIR is not reached, and the TPC of the own station increases “1 (up)” or decreases. It is biased toward “0 (down)”.

  Therefore, the base station calculates a ratio (Up rate) where the TPC is “1” in a predetermined period (arbitrarily set), and makes a final determination based on the ratio. For example, the period Tb is used as the predetermined period. The base station calculates the TPC Up rate, and compares the calculated Up rate with predetermined upper and lower thresholds set in advance in the own station. And when it has the relationship of lower limit threshold value <Up rate <upper limit threshold value (YES of step S63 ("positive")), it is judged that TPC is not biased. As a result, the base station determines that it is selected as the primary base station from the mobile station 4 (step S64).

  In addition, when the relationship of lower limit threshold <Up rate <upper limit threshold is not satisfied, it is determined that the TPC is biased. As a result, the base station determines that it is not selected as the primary base station from the mobile station 4 (step S65).

  As described above, according to the fifth embodiment, by using the first determination based on the primary base station ID and the second determination based on the TPC, it is determined whether the base station is selected as the primary base station by the mobile station. Can be performed with high reliability. Therefore, it is possible to reduce problems such as an increase in interference and a decrease in channel utilization efficiency due to erroneous data transmission even though the mobile communication terminal which is a mobile station is not requested to transmit data. .

The block diagram of the mobile communication system which concerns on each Example of this invention. The block diagram of the mobile station which concerns on each Example of this invention. The block diagram of the base station which concerns on each Example of this invention. The sequence which shows transmission power control of the mobile communication system in Example 1 of this invention. The sequence which shows transmission power control of the mobile communication system in Example 2 of this invention. The sequence which shows transmission power control of the mobile communication system in Example 3 of this invention (when switching to a base station with a bad upstream propagation environment quality). The sequence which shows transmission power control of the mobile communication system in Example 3 of this invention (when switching to the base station with favorable uplink propagation environment quality). The sequence which shows transmission power control of the mobile communication system in Example 4 of this invention. The flowchart which shows operation | movement of the base station in Example 5 of this invention.

Explanation of symbols

1, 2, 3 Base station 4 Mobile station 11 Antenna 12 Radio processing unit 13 Synchronization processing unit 14 Signal processing unit 15 Separation processing unit 16 Decoding processing unit 17 Received data control unit 18 Received power measurement unit 19 Base station selection unit 20 Power control Command extraction unit 21 Transmission data control unit 22 Transmission power control unit 23 Transmission processing unit 31, 32, 33 Power control command 34 Internal power control command 51 Antenna 52 Wireless processing unit 53 Reception data control unit 54 User management unit 55 Transmission data control unit 56 transmission processing unit 60 reception processing unit 61 synchronization processing unit 62 signal processing unit 63 separation processing unit 64 decoding processing unit 65 primary base station ID extraction unit 66 reception power measurement unit 67 power control command generation unit

Claims (12)

Base station selection means for selecting a primary base station as a data transmission source from a plurality of base stations of the active set;
Transmitting means for transmitting a primary base station ID indicating the primary base station selected by the base station selecting means to a plurality of base stations of the active set at a predetermined transmission power by an uplink control channel;
Receiving means for receiving a plurality of power control command signals transmitted from a plurality of base stations of the active set and a data signal transmitted from a base station selected as the primary base station;
The uplink control channel at the time of transmitting the primary base station ID by the power control command signal from the base station selected as the primary base station from the plurality of power control command signals received by the receiving means. A mobile station comprising transmission power control means for controlling transmission power. Base station selection means for selecting a primary base station as a data transmission source from a plurality of base stations of the active set;
Transmitting means for transmitting a primary base station ID indicating the primary base station selected by the base station selecting means to a plurality of base stations of the active set at a predetermined transmission power by an uplink control channel;
Receiving means for receiving a plurality of power control command signals transmitted from a plurality of base stations of the active set and a data signal transmitted from a base station selected as the primary base station;
When the primary base station is changed, the uplink control channel is transmitted by the power control command signal from the base station selected as the changed primary base station from a predetermined time before the changed primary base station ID transmission. A mobile station comprising transmission power control means for controlling power. Base station selection means for selecting a primary base station as a data transmission source from a plurality of base stations of the active set;
Transmitting means for transmitting a primary base station ID indicating the primary base station selected by the base station selecting means to a plurality of base stations of the active set at a predetermined transmission power by an uplink control channel;
Receiving means for receiving a plurality of power control command signals transmitted from a plurality of base stations of the active set and a data signal transmitted from a base station selected as the primary base station;
A ratio of a command for requesting power increase from the plurality of power control command signals received by the receiving unit within a predetermined period is calculated for each of the plurality of base stations, and the uplink propagation environment quality of the uplink control channel is calculated based on the ratio. An uplink propagation environment determining means for determining;
When changing the primary base station, the uplink propagation environment quality of the base station selected as the changed primary base station based on the uplink propagation environment determining means is selected as the primary base station before the change If the quality of the uplink propagation environment of the base station is worse, the uplink control is performed by the power control command signal from the base station selected as the changed primary base station from a predetermined time before the changed primary base station ID transmission. A mobile station comprising transmission power control means for controlling transmission power of a channel. The transmission power control means includes
When changing the primary base station, the uplink propagation environment quality of the base station selected as the changed primary base station based on the uplink propagation environment determining means is selected as the primary base station before the change When the uplink propagation environment quality of the base station is better, the transmission power of the uplink control channel is determined by the power control command signal from the base station selected as the changed primary base station when the changed primary base station ID is transmitted. The mobile station according to claim 3, wherein the mobile station is controlled. Base station selection means for selecting a primary base station as a data transmission source from a plurality of base stations of the active set;
Transmitting means for transmitting system essential information to be transmitted to a plurality of base stations of the active set to a plurality of base stations of the active set with a predetermined transmission power by an uplink control channel;
Receiving means for receiving a plurality of power control command signals transmitted from a plurality of base stations of the active set and a data signal transmitted from a base station selected as the primary base station;
A ratio of a command for requesting power increase from the plurality of power control command signals received by the receiving unit within a predetermined period is calculated for each of the plurality of base stations, and the uplink propagation environment quality of the uplink control channel is calculated based on the ratio. An uplink propagation environment determining means for determining and extracting a base station having the worst uplink propagation environment quality;
Transmission power control means for controlling the transmission power of the uplink control channel by the power control command signal from the base station having the worst uplink propagation environment quality from a predetermined time before the system essential information transmission timing. A featured mobile station.   The mobile station according to any one of claims 1 to 5, wherein a channel of the data signal is a high-speed shared channel or a dedicated channel. In a mobile communication system for performing wireless communication between a mobile station and a plurality of base stations of an active set,
The mobile station
Base station selection means for selecting a primary base station to be a data transmission source from a plurality of base stations of the active set;
Transmitting means for transmitting a primary base station ID indicating the primary base station selected by the base station selecting means to a plurality of base stations of the active set at a predetermined transmission power by an uplink control channel;
Receiving means for receiving a plurality of power control command signals transmitted from a plurality of base stations of the active set and a data signal transmitted from a base station selected as the primary base station;
The uplink control channel at the time of transmitting the primary base station ID by the power control command signal from the base station selected as the primary base station from the plurality of power control command signals received by the receiving means. Transmission power control means for controlling transmission power,
The base station
A received power measuring means for calculating a received power parameter of a signal transmitted from the mobile station by the uplink control channel;
Transmission information control means for generating and transmitting the power control command for instructing increase / decrease of the transmission power of the uplink control channel based on the reception power parameter calculated by the reception power measurement means. A mobile communication system. In a mobile communication system for performing wireless communication between a mobile station and a plurality of base stations of an active set,
The mobile station
Base station selection means for selecting a primary base station to be a data transmission source from a plurality of base stations of the active set;
Transmitting means for transmitting a primary base station ID indicating the primary base station selected by the base station selecting means to a plurality of base stations of the active set at a predetermined transmission power by an uplink control channel;
Receiving means for receiving a plurality of power control command signals transmitted from a plurality of base stations of the active set and a data signal transmitted from a base station selected as the primary base station;
When the primary base station is changed, the uplink control channel is transmitted by the power control command signal from the base station selected as the changed primary base station from a predetermined time before the changed primary base station ID transmission. Transmission power control means for controlling power,
The base station
A received power measuring means for calculating a received power parameter of a signal transmitted from the mobile station by the uplink control channel;
Transmission information control means for generating and transmitting the power control command instructing increase / decrease of the transmission power of the uplink control channel based on the reception power parameter calculated by the reception power measurement means, Mobile communication system. In a mobile communication system for performing wireless communication between a mobile station and a plurality of base stations of an active set,
The mobile station
Base station selection means for selecting a primary base station to be a data transmission source from a plurality of base stations of the active set;
Transmitting means for transmitting a primary base station ID indicating the primary base station selected by the base station selecting means to a plurality of base stations of the active set at a predetermined transmission power by an uplink control channel;
Receiving means for receiving a plurality of power control command signals transmitted from a plurality of base stations of the active set and a data signal transmitted from a base station selected as the primary base station;
A ratio of a command for requesting power increase from the plurality of power control command signals received by the receiving unit within a predetermined period is calculated for each of the plurality of base stations, and the uplink propagation environment quality of the uplink control channel is calculated based on the ratio. An uplink propagation environment determining means for determining;
When changing the primary base station, the uplink propagation environment quality of the base station selected as the changed primary base station based on the uplink propagation environment determining means is selected as the primary base station before the change If the quality of the uplink propagation environment of the base station is worse, the uplink control is performed by the power control command signal from the base station selected as the changed primary base station from a predetermined time before the changed primary base station ID transmission. Transmission power control means for controlling the transmission power of the channel,
The base station
A received power measuring means for calculating a received power parameter of a signal transmitted from the mobile station by the uplink control channel;
Transmission information control means for generating and transmitting the power control command instructing increase / decrease of the transmission power of the uplink control channel based on the reception power parameter calculated by the reception power measurement means, Mobile communication system. The transmission power control means of the mobile station is
When changing the primary base station, the uplink propagation environment quality of the base station selected as the changed primary base station based on the uplink propagation environment determining means is selected as the primary base station before the change When the uplink propagation environment quality of the base station is better, the transmission power of the uplink control channel is determined by the power control command signal from the base station selected as the changed primary base station when the changed primary base station ID is transmitted. The mobile communication system according to claim 9, wherein the mobile communication system is controlled. The base station
A first determination means for comparing the primary base station ID transmitted from the mobile station with an ID held by the mobile station, and determining that the primary base station is selected by the primary base station if they match;
A second determination unit that calculates an increase rate of the power control command signal within a predetermined period and determines that the primary base station is selected when it is between a predetermined upper threshold and a lower threshold; And
The mobile communication system according to any one of claims 7 to 10, wherein selection of the primary base station is determined by the first determination unit and the second determination unit. In a base station of a mobile communication system that performs radio communication between a mobile station and a plurality of base stations of an active set,
Received power measuring means for calculating an uplink received power parameter of a signal transmitted by an uplink control channel from the mobile station;
Transmission information control means for generating and transmitting a power control command instructing increase / decrease in transmission power of the uplink control channel;
A first determination means for comparing a primary base station ID indicating a primary base station transmitted from the mobile station with an ID held by the own station, and determining that the primary base station is selected if the IDs match; ,
A second determination unit that calculates an increase rate of the power control command within a predetermined period and determines that the primary base station is selected when it is between a predetermined upper limit threshold and a lower limit threshold; A base station for a mobile communication system.

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