JP5213628B2 - Relay transceiver - Google Patents

Description

  The present invention relates to a relay transmission / reception apparatus that relays radio transmission / reception performed between a mobile station and a base station.

  The relay transmitting / receiving apparatus is installed between the base station and the mobile station, and amplifies the signals with an appropriate gain (hereinafter also referred to as a relay gain) when relaying bidirectional signals. The operation of automatically amplifying the signal is called an AGC (Automatic Gain Control) operation. For example, even if there is a mobile station in a shadowing area such as indoors where zone reduction or call quality degradation occurs, the relay transmission / reception device amplifies the signal between the base station and the mobile station with an appropriate gain, The base station and the mobile station can perform good communication with each other. Various inventions have been made regarding a method of selecting a relay channel in a relay transmitting / receiving apparatus.

  For example, the invention described in Patent Document 1 describes a channel selection method that improves the throughput based on the received electric field strength and the interference state. Further, in the invention described in Patent Document 2, the order of the reception channels is changed according to the determination as to whether or not a desired transmission signal is included in the reception channel.

  In a conventional relay transmission / reception device, when selecting a reception channel to be used for receiving a signal from a base station, the received signals are in a fixed order such as ascending order of channels or descending order (for example, ascending order of frequencies or descending order). Scan the reception level (power level). Then, one channel having the highest reception level and reception CINR is selected as a relay channel. When the reception level of the channel among the plurality of received channels becomes the same value, one channel is selected according to the priority order such as ascending / descending order between the channels at the same level.

JP 2006-254326 A Japanese Patent No. 2008-118195

  However, in the conventional channel selection method, many relay transmission / reception apparatuses tend to select a specific channel in a biased manner. In particular, when the number of channels is only 2 to 3 as in a broadband wireless access system, or when all base stations use the same channel due to application of FFR technology or the like, the above-described channel scanning method is determined. There is a high possibility that only the channel is selected. As a result, many relay transmission / reception apparatuses concentrate on selecting only a specific channel, which increases the traffic load on the specific channel. As a result, the relay transmission / reception apparatus has a problem that it cannot accommodate all mobile terminals to be relayed.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a relay transmission / reception apparatus capable of ensuring reception quality and reducing the traffic load on a channel. .

The relay transmission / reception apparatus according to the present invention is used in a system in which the reception level decreases when the amount of data is small, and receives the signal to which the first and second signals from the base station are added for each channel. And the gate control part which outputs the timing which should detect each of the said 1st, 2nd signal from the said signal is provided. A reception level detection unit that detects the reception levels of the first and second signals from the signal for each channel based on the timing output from the gate control unit. The reception level of the second signal detected by the reception level detection unit is the lowest among the channels in which the reception level of the first signal detected by the reception level detection unit is equal to or greater than a certain value. A channel selection unit for selecting one channel is provided.

  According to the relay transmission / reception apparatus of the present invention, the channel having the lowest reception level of the second signal is selected from the channels in which the reception level of the first signal is a certain value or more. Therefore, the reception quality can be ensured and the traffic load on the channel can be reduced.

<Embodiment 1>
FIG. 1 is a diagram showing a configuration of a mobile communication system including a relay transmission / reception apparatus according to the present embodiment. As shown in the figure, the mobile communication system includes a base station 1, mobile terminals 2 and 3, and a relay transmitting / receiving apparatus (hereinafter also referred to as a repeater) 10. The mobile terminal 2 is a mobile terminal under the base station 1. The relay transmission / reception device 10 relays wireless transmission / reception performed between the mobile terminal 3 in the shadowing region (shadowing region) 4 and the base station 1.

  The repeater 10 receives a radio signal having a frequency f1 or f2 (f1 ≠ f2) transmitted from the base station 1 (downward reception), and receives a signal having one of the two frequencies, for example, another signal. The frequency is converted to f3 and transmitted to the mobile terminal 3 (downlink transmission). Further, the repeater 10 receives the signal of the frequency f3 transmitted from the mobile terminal 3 (uplink reception), converts the signal into any one of the above-mentioned frequencies and transmits it to the base station 1 (uplink transmission). . In the downlink (downlink), downlink reception and downlink transmission are performed, and in the uplink (uplink), uplink reception and uplink transmission are performed.

  FIG. 2 is a diagram showing a configuration of the repeater 10 according to the present embodiment. As shown in the figure, the repeater 10 includes a base station (terminal) side antenna 11 (21), a base station (terminal) side antenna filter 101 (201), and a base station (terminal) side TDD switch 102 (202). , Base station (terminal) side LNA 103 (203), base station (terminal) side down converter 104 (204), base station (terminal) side receiving AGC amplifier 105 (205), base station (terminal) side HPA 106 ( 206), base station (terminal) side upconverter 107 (207), base station (terminal) side transmission baseband amplifier 108 (208), base station (terminal) side local oscillation circuit (synthesizer) 109 (209) The adjacent channel elimination filter 111 (211), the base station (terminal) side reception level detection circuit 112 (212), and the base station (terminal) side AGC control circuit 1 It includes 3 (213), a gate control circuit 151, a channel selection circuit 161, and a frame synchronization control circuit 301.

  The frame synchronization control circuit 301 controls frame synchronization based on a signal from the base station 1. The frame synchronization control circuit 301 according to the present embodiment detects timing from the signal from the base station 1 and controls the above-described base station (terminal) side TDD switch 102 (202) based on the timing. To switch between uplink and downlink. This method is called a TDD (Time Division Duplex) method.

  An external signal received by the base station (terminal) side antenna 11 (21) passes through the base station (terminal) side LNA 103 (203) from the base station (terminal) side antenna filter 101 (201), and then passes through the base station (terminal) side antenna (101). It is down-converted to a baseband signal by the terminal-side down converter 104 (204). These downconverters are also called quadrature detectors. A signal from the base station (terminal) side down converter 104 (204) is output to the base station (terminal) side reception AGC amplifier 105 (205). The base station (terminal) side reception AGC amplifier 105 (205) amplifies the signal received by the base station side (terminal) side antenna 11 (21) in a variable gain.

  The adjacent channel removal filter 111 (211) suppresses an adjacent channel component of a desired signal among signals amplified by the base station (terminal) side reception AGC amplifier 105 (205). The terminal (base station) side up-converter 207 (107) up-converts the signal from the adjacent channel removal filter 111 (211) via the terminal (base station) side transmission baseband amplifier 208 (108) to the transmission frequency. . The signal output from the terminal (base station) side up-converter 207 (107) is transmitted to the outside from the terminal (base station) side antenna 21 (11) via the terminal (base station) side HPA 206 (106). .

  The terminal side reception level detection circuit 212 detects the reception level of the signal from the mobile terminal 3. The terminal-side AGC control circuit 213 uses the reception level detected by the terminal-side reception level detection circuit 212 as control information for the terminal-side reception AGC amplifier 205 as reception field strength information from the mobile terminal 3.

  FIG. 3 is a diagram illustrating a signal received by the base station side antenna 11. The base station side antenna 11 transmits and receives the signals in FIG. 3 in order from the left side to the right side. A downlink subframe (DL subframe) signal 50 is a signal transmitted from the base station 1, and an uplink subframe (UL subframe) signal 60 is a signal transmitted from the mobile station 3. A protection time (TDD guard time) for switching between transmission and reception is provided between the DL subframe signal 50 and the UL subframe signal 60.

  In the present embodiment, the DL subframe signal 50 includes a preamble signal 51, a MAP signal 52, and a communication data signal 53. The relay transmitting / receiving apparatus 10 according to the present embodiment receives a DL subframe signal 50, which is a signal to which a first signal and a second signal from the base station 1 are added, for each channel. In the present embodiment, the first signal includes the preamble signal 51 of the downlink subframe signal 50, and the second signal includes the communication data signal 53 of the downlink subframe signal 50. The preamble signal 51 is a signal for informing the start of a frame. The MAP signal 52 is a signal regarding a protocol for performing mobility management control such as location registration and authentication. The communication data signal 53 is a signal for data to be communicated.

  The gate control circuit 151 which is a gate control unit included in the relay transmission / reception apparatus 10 according to FIG. 2 determines the timing at which the preamble signal 51 and the communication data signal 53 should be detected from the DL subframe signal 50 from the base station 1. Output. In the present embodiment, the gate control circuit 151 outputs the timing at which these signals should be detected based on the timing information output from the frame synchronization unit 301.

  Based on the timing output from the gate control circuit 151, the base station side reception level detection circuit 112, which is the reception level detection unit according to the present embodiment, converts the preamble signal 51 and communication data from the signal from the base station 1. The reception level of the signal 53 is detected for each channel. The base station side AGC control circuit 113 uses the reception level of the preamble signal 51 detected by the base station side reception level detection circuit 112 as control information for the base station side reception AGC amplifier 105 as reception field strength information from the base station 1. .

  A channel selection circuit 161 which is a channel selection unit according to the present embodiment scans the frequency of the base station side local oscillation circuit 109. Then, the channel selection circuit 161 according to the present embodiment has the base station side reception level detection circuit 112 out of the channels in which the reception level of the preamble signal 51 detected by the base station side reception level detection circuit 112 is equal to or higher than a certain value. The first channel with the lowest reception level of the communication data signal 53 detected in step 1 is selected.

  If the base station-side reception level detection circuit 112 can simultaneously measure the reception level of the preamble signal 51 and the reception level of the communication data signal 53, the channel selection circuit 161 can perform one measurement in one scan. A channel may be selected. Otherwise, the channel selection circuit 161 selects a channel in which the reception level of the preamble signal 51 is a certain value or more in the first scan, and in the next scan, of the communication data signal 53 among the selected channels. One channel with the lowest reception level may be selected.

  In the relay transmitting / receiving apparatus 10 according to the present embodiment as described above, a channel is selected in which the reception level of the preamble signal 51 is a certain value or more. This makes it possible to select a channel for which reception quality is ensured. Also, in relay transmission / reception apparatus 10 according to the present embodiment, one of the channels having the lowest reception level of communication data signal 53 is selected as a relay channel. In general, in the case of an OFDM / OFDMA system, the amount of data transmitted as a radio signal is proportional to the number of subcarriers transmitted. Therefore, when the amount of data is small, the reception level of the radio signal is small. Therefore, if one channel with the lowest reception level of the communication data signal 53 is selected, a channel with a low traffic load is selected. Thus, the relay transmitting / receiving apparatus 10 according to the present embodiment performs such selection, so that the reception quality can be ensured and the traffic load on the channel can be reduced.

  In the relay transmitting / receiving apparatus 10 described above, one channel is selected based on the preamble signal 51 and the communication data signal 53 of the DL subframe signal 50 according to FIG. However, the present invention is not limited to this, and the following relay transmitting / receiving apparatus 10 may be used. At the start of relaying, the UL subframe signal 60 is received from the base station side antenna 11. By using this, the relay transmitting / receiving apparatus 10 uses the uplink subframe signal 60 as the third signal from the mobile terminal 3 and the signal to which the preamble signal 51 and the communication data signal 53 from the base station 1 are added. Are received for each channel by the base station side antenna 11. The gate control circuit 151 determines the timing for detecting the preamble signal 51, the communication data signal 53, and the UL subframe signal 60 from the DL subframe signal 50 from the base station 1 and the UL subframe signal 60 from the mobile terminal 3, respectively. Output.

  Based on the timing output from the gate control circuit 151, the base station side reception level detection circuit 112 extracts the preamble signal 51, the communication data signal 53, and the UL subframe signal 60 from the signals from the base station 1 and the mobile terminal 3. The reception level is detected for each channel. The channel selection circuit 161 includes a communication data signal 53 detected by the base station side reception level detection circuit 112 among the channels in which the reception level of the preamble signal 51 detected by the base station side reception level detection circuit 112 becomes a predetermined value or more. One channel having the lowest reception level and the reception level of the UL subframe signal 60 is selected. For example, the channel having the smallest sum of the reception level of the communication data signal 53 and the reception level of the UL subframe signal 60 and the smallest difference between the reception levels is selected.

  According to such a relay transmission / reception device, it is possible to select a channel with a smaller traffic load as a relay channel more reliably than the relay transmission / reception device described above.

  In any of the above-described relay transmission / reception apparatus and the relay transmission / reception apparatus described herein, the gate control circuit 151, the base station side reception level detection circuit 112, and the channel selection circuit 161 are periodically operated. It is preferable. In the case of a configuration that operates in this way, a channel with a small traffic load is periodically selected again, so that a fixed transmission load bias can be prevented.

1 is a diagram showing a configuration of a mobile communication system according to Embodiment 1. FIG. 1 is a diagram illustrating a configuration of a relay transmission / reception device according to Embodiment 1. FIG. 6 is a diagram illustrating a signal received by the relay transmission / reception apparatus according to Embodiment 1. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Base station, 2, 3 Mobile terminal, 4 Shadowing area | region, 10 Relay transmission / reception apparatus, 11 Base station side antenna, 21 Terminal side antenna, 50 DL sub-frame signal, 51 Preamble signal, 52 MAP signal, 53 Communication data signal, 60 UL subframe signal, 101 Base station side antenna filter, 102 Base station side TDD switch, 103 Base station side LNA, 104 Base station side down converter, 105 Base station side reception AGC amplifier, 106 Base station side HPA, 107 Base station Side up-converter, 108 base station side transmission baseband amplifier, 109 base station side local oscillation circuit, 111, 211 adjacent channel elimination filter, 112 base station side reception level detection circuit, 113 base station side AGC control circuit, 151 gate control circuit 161 channel selection , 201 Terminal side antenna filter, 202 Terminal side TDD switch, 203 Terminal side LNA, 204 Terminal side down converter, 205 Terminal side reception AGC amplifier, 206 Terminal side HPA, 207 Terminal side up converter, 208 Terminal side transmission baseband amplifier 209 Terminal local oscillation circuit 212 Terminal reception level detection circuit 213 Terminal AGC control circuit 301 Frame synchronization control circuit

Claims (5)

A relay transmission / reception device that is used in a system in which a reception level is reduced when a data amount is small and receives a signal to which a first and second signal from a base station is added for each channel,
A gate control unit for outputting a timing at which each of the first and second signals should be detected from the signal;
Based on the timing output from the gate control unit, a reception level detection unit that detects the reception level of the first and second signals from the signal for each channel;
Among the channels in which the reception level of the first signal detected by the reception level detection unit is equal to or higher than a certain value, the reception level of the second signal detected by the reception level detection unit is the smallest. A channel selection unit for selecting a channel,
Relay transmission / reception device. Used for a system in which the reception level is small when the amount of data is small, and receives a signal to which the first and second signals from the base station are added and a third signal from the mobile station for each channel. A transmission / reception device,
A gate control unit for outputting a timing at which each of the first to third signals should be detected from the signal and the third signal;
A reception level detection unit that detects reception levels of the first to third signals from the signal and the third signal based on the timing output from the gate control unit;
Among the channels in which the reception level of the first signal detected by the reception level detection unit is a certain value or more, the reception level of the second signal detected by the reception level detection unit, and the first A channel selection unit that selects one channel having the smallest reception level of the three signals and the smallest difference between the reception levels.
Relay transmission / reception device.
The first signal includes a preamble signal of a downlink subframe signal,
The relay transmission / reception apparatus according to claim 1 or 2. The second signal includes a communication data signal of a downlink subframe signal,
The relay transmission / reception apparatus according to any one of claims 1 to 3. The third signal includes an uplink subframe signal,
The relay transmission / reception apparatus according to claim 2.

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