JPH0373627A - Base station reception system - Google Patents

Abstract

PURPOSE:To set a line with an optimum mobile equipment with simple circuit constitution automatically and to simplify the control and circuit constitution by providing a signal selection function and an inter-base station signal relay function to each base station without a definite selection control requiring a large scale circuit. CONSTITUTION:Base stations 2 are interconnected together and a signal 100 from one mobile equipment 1 is received by a base station group 101 comprising the plural base stations interconnected together. The reception information from the mobile equipment 1 is transferred through the interconnected base stations 2, each base station 2 compares a reception signal S/N with the S/N of the signal 103 transferred from its adjacent base station 2, a signal with higher S/N is selected by a signal selection switch 102 and the result is sent to a succeeding adjacent base station 2 as a reception signal from the mobile equipment 1. The signal is transferred through the base stations 2 in this way and the reception signal from the mobile equipment 1 having the highest S/N is outputted finally from the final stage base station 104 and sent to a ground system network 105.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a base station reception system that efficiently receives and demodulates signals from mobile devices using a simple demodulation circuit without performing complicated switching control.

[Prior Art] Conventionally, this type of receiving system has been configured as shown in FIG. 1 is a mobile device, 2 is a base station, 3 is a transmission signal, 4 is a demodulation circuit, 5 is a demodulation signal, 6 is a received signal S/N detection circuit, 7
8 is a switching selection circuit, and 8 is a final demodulated signal.

This method is generally called selection diversity, and is
The signals transmitted from the base station 2 are received and demodulated by each base station 2, and the demodulated signal with the highest S/N among the demodulated signals is selected by the switching selection circuit 7 based on the information from the S/N detection circuit 6. , and finally outputs a demodulated signal 8 with improved S/N.

In this way, the S/N of demodulated signals at all base stations is estimated and selective demodulation is performed by the switching selection circuit 7.
It is necessary to collect S/N information of all base station demodulated signals and to perform unified selection control, which has the disadvantage of complicating the control and circuit configuration. In addition, all the base stations and the switching selection circuit 7 had to be connected by wires, which resulted in a large number of connections and a problem with reliability.

FIG. 7 shows another conventional example, in which 9 is a received signal S/N detection circuit, 10 is a weighting circuit, 12 is a signal synthesis circuit, and 1
3 is a demodulated signal with improved S/N.

This method is generally called composite diversity, and is
Each base station 2 receives and demodulates the signal transmitted from the base station 2, weights each demodulated signal in proportion to the S/N, and then performs level synthesis in the signal synthesis circuit 12, and finally calculates the S/N. This is a method for extracting an improved demodulated signal 13.

After performing weighting in this way, signal synthesis is performed, so
It is necessary to install an S/N detection circuit and a weighting circuit for each base station, and since the signals of all base stations are combined at once, there is a drawback that the signal combining circuit becomes complicated.

Furthermore, since S/N detection requires long-term averaging, there is a drawback that the S/H estimation speed cannot be increased.

In addition, all the base stations and the signal synthesis circuit must be connected by wires, resulting in a large number of connections and a problem with reliability.

[Problems to be Solved by the Invention] In order to eliminate these drawbacks, the present invention provides each base station with a signal selection function and an inter-base station signal relay function without performing unified selection control that requires a large-scale circuit. It is an object of the present invention to provide a base station reception system that can automatically set up an optimal line with a mobile device with a simple circuit configuration.

[Means and effects for solving the problem] In order to achieve the above object, the present invention simultaneously receives and demodulates signals transmitted from a mobile device at a plurality of base stations, and combines or selects the plurality of demodulated signals. In communication systems, connections between base stations are connected in a linear, tree-like, or ring-like manner, and signals are received from mobile devices and received information is transferred through the connected base stations. The signal demodulated at one base station is sent to the next base station, and the next base station combines the signal sent from the previous base station and the signal decoded at its own station, or combines the signal sent from the previous base station with the signal decoded at its own station, or combines the signal sent from the previous base station with the signal decoded at its own station. The base stations are connected to each other so that the signal is selected and sent to the next base station, and the line quality of the signal between base stations improves each time it passes through the base station, and the connected base station is the final stage. It is characterized by extracting reception information with the best line quality among the base stations that received the signal from the mobile device, and at each base station, the received demodulated signal from the mobile device and the received information from the adjacent base station are transferred. By combining or selecting the received demodulated signals, the quality of the received demodulated signals is improved and information from the mobile device is transferred, so all the received and demodulated signals are brought into one place and selected or selected. Compared to the synthesis method, control and circuit configuration are simpler. Further, by setting a plurality of signal transfer routes between base stations, it is possible to prevent deterioration due to failures in base station circuits and connections between base stations. Furthermore, by connecting base stations in a tree-like manner and adding new base stations at the tip, it is possible to easily add base stations with less influence on the entire system.

[Example] FIG. 1 shows one embodiment of the present invention, which will be explained below.

The configuration of this method is as follows. 1 is a mobile device, 2 is a base station, 4 is a demodulation circuit of each base station, 5 is a demodulated signal, 100 is a signal transmitted from the mobile device, 101 is a base near the mobile device that receives the signal transmitted from the mobile device Station group, 102 is a signal selection switch, 103 is a signal transferred between base stations, 10
4 is a base station that outputs the final received information, and 105 is a ground network.

The operation of this method is as follows. The base stations are connected together, and a signal 100 emitted from one mobile device is received by a group of connected base stations 101. Received information from mobile devices is transferred via the connected base stations 2, and each base station compares the S/N of its own received signal with the S/N of the signal 103 transferred from the adjacent base station, and The signal with higher /H is selected by the signal selection switch 102 and transmitted to the next adjacent base station as a received signal from the mobile device. By passing through the base stations one after another in this way, the received signal from the mobile device with the highest S/N is finally output from the final stage base station 104 and transmitted to the terrestrial network 105.

FIG. 2 shows the process of transmitting signals from a mobile device in this system. 1 is a mobile device, 2 is a base station, 4 is a demodulation circuit of each base station, 5 is a demodulation signal, 102 is a signal selection switch, 106
is the received signal of the A base station, 107 is the received signal of the B base station,
108 is a received signal from the C base station, and 109 is a received signal from the D base station.

A signal emitted from a mobile device is received by base stations A, B, C, and D. If the received signal S/N of station 0 is the highest among these four stations, it is received and transferred by stations A and B. The received signal at station 0 is cut off by a signal selection switch at station 0, and the received signal at station 0 is transferred to station D, which is the next base station. At station D, the S/N of the received signal transferred from station 0 is higher than the S/N of the own station received signal, so the transferred received signal is selected by the signal selection switch and sent to the next base station. sent to.

The specific circuit configuration used in this method is as follows. Third
The figure shows the specific circuit configuration. 1 is a mobile device, 2 is a base station, 3 is a transmission signal, 4 is a demodulation circuit of each base station, 5 is a demodulation signal, 9 is a received signal S/N detection circuit, 109 is a signal transferred from an adjacent base station , 110 is an S/N information extraction circuit, 111 is S/N information of the own station received signal,
112 is S/N information of a demodulated signal transferred from a connected adjacent base station; 113 is an S/N comparison circuit; 114
102 is a switching information, 102 is a switching selection circuit, 115 is an S/N information insertion circuit, 116 is a signal transfer circuit to an adjacent base station, and 103 is an inter-base station transfer signal.

The specific operation of this circuit is as follows. A transmission signal 3 transmitted from the mobile device 1 is received by a plurality of base stations 2.

Next, in each base station, the demodulation circuit 4 demodulates the received signal, and at the same time, the received signal S/N detection circuit 9 detects the S/N of the received signal. S/N information 111 of this detected received signal
is compared with the S/N information 112 of the demodulated signal transferred from the connected adjacent base station by the S/N comparison circuit 113, and the demodulated signal with the higher S/N is selected by the switching selection circuit 102. . The selected demodulated signal is transferred after the S/N information of the signal is inserted by the S/N information insertion circuit 115. As a result, the S/N ratio is improved each time the signal passes through the base station.

FIG. 4 shows another embodiment of the present invention, which will be described below.

1 is a mobile device, 2 is a base station, 4 is a demodulation circuit of each base station, 5
is a demodulated signal, 100 is a signal transmitted from the mobile device, 11
7 is a received signal from a mobile device that is transferred between base stations connected in a ring; 102 is a signal selection switch; 118 is a base station that outputs received information to the terrestrial network; 105
is the terrestrial network.

The operation of this embodiment is as follows. The base stations are connected in a ring, and a signal 100 emitted from one mobile device is received by a plurality of base stations 2 connected in a ring.

Received information from the mobile device is transferred via the connected base station 2, and each base station compares its own received signal S/N with the signal S/N transferred from the adjacent base station, and determines the S/N. The signal with the higher value is selected by the signal selection switch 102 and transmitted to the next adjacent base station as the received signal from the mobile device. By passing through the base stations one after another in this way, the quality of the received signal is improved, and the signal passes through the ring-connected inter-base station signal transfer path. Finally, the base station 118 that outputs terrestrial network reception information confirms that the quality of the received signal from the mobile device is above a certain level, and then transmits the received signal to the terrestrial network 105.

FIG. 5 shows another example of the present invention, which will be explained below.

The configuration of this method is as follows. 200 is a mobile station encoding circuit, 201 is a mobile station transmitting circuit, 202 is a maximum likelihood decoding circuit, 203 is a likelihood of a signal received by the own station, and 204 is a transfer including the likelihood of a signal transferred from an adjacent base station. 205 is a decoded signal, 206 is a base station encoding circuit, 207 is a likelihood of the decoded signal generated within the decoding circuit, and 208 is a multiplication circuit for giving a likelihood to the re-encoded signal.

The operation of this method is as follows. Mobile device encoding circuit 2
The signal encoded by 00 is transmitted to multiple base stations. Each base station demodulates the transmitted signal and performs maximum likelihood decoding. At this time, not only the demodulated signal of the own station but also the transfer signal including the likelihood indicating the quality of the signal transferred from the adjacent base station are simultaneously fetched and decoded. Next, the likelihood 207 obtained during decoding is extracted from the maximum likelihood decoding circuit and is used as the quality of the decoded signal, which is the received information from the mobile device that can be detected by the base station. Finally, the encoding circuit 206 and the multiplication circuit 20g for giving a likelihood to the re-encoded signal generate transfer information to which a likelihood indicating the quality of the received information is added, and the generated information is transferred to the next adjacent base station. Here, the transfer signal to which the likelihood has been added by the multiplier circuit is a signal obtained by adding a level fluctuation proportional to the likelihood value to the digital data of "1" and "0" in an analog manner, or a signal transmission rate between base stations. This signal converts one bit of transfer data into several bits of soft data.

The following three methods are used to detect received signal quality in this method.
There is a method.

Method 1 The format of the signal transmitted from the mobile device to the base station is configured to have a fixed pattern for each frame, and the base station detects the number of error bits included in this fixed pattern and estimates the quality of the received signal.

■Method 2 At the base station, the received level or phase error of the signal from the mobile device is measured to estimate the quality of the received signal.

■Method 3: Use encoded signals for the signals transmitted from the mobile device to the base station,
At the base station, the quality of the received signal is estimated using the likelihood obtained during maximum likelihood decoding or syndrome bits based on parity check.

This method can be applied to selecting the optimal base station for transmitting to a mobile device. Each base station compares the quality of its own received signal with the quality of the signal transferred from neighboring base stations, and always selects and relays the signal with the highest quality, making it possible to reversely transfer signals from the terrestrial network. This makes it possible to always transmit signals from a mobile device and a base station with good radio circuits.

[Effects of the Invention] As explained above, each base station combines or selects the received demodulated signal from the mobile device and the received demodulated signal transferred from the adjacent base station, thereby improving the quality of the received demodulated signal and improving the quality of the received demodulated signal. Since the configuration is such that information from the mobile device is transferred, the control and circuit configuration are simpler than a system in which all received and demodulated signals are brought into one location and selected or combined. Further, by setting a plurality of signal transfer routes between base stations, it is possible to prevent deterioration due to failures in base station circuits and connections between base stations. Furthermore, by connecting base stations in a tree-like manner and adding new base stations at the tip, it is possible to easily add base stations with less influence on the entire system.

[Brief explanation of drawings]

1 to 3 are configuration explanatory diagrams showing one embodiment of the present invention,
4 and 5 are configuration explanatory diagrams showing other embodiments of the present invention, FIG. 6 is a configuration explanatory diagram showing conventional selection diversity,
FIG. 7 is a configuration explanatory diagram showing conventional synthetic diversity. 1... Mobile device, 2... Base station, 4... Demodulation circuit,
9... Received signal S/N detection circuit, 100... Receiving circuit, 101... S/N information extraction circuit, 113...
・S/N comparison circuit, 102... switching selection circuit, 1
15... S/N information insertion circuit, 116... signal transfer circuit.

Claims (3)

[Claims] (1) In a communication system that improves line quality by simultaneously receiving and demodulating signals transmitted from a mobile device at multiple base stations and combining or selecting the demodulated signals, the connection between base stations is They are connected in a linear, tree-like, or ring-like manner, and receive signals from mobile devices and transfer received information through the connected base stations, and send signals demodulated at one base station to the next base station. , the next base station combines the signal sent from the previous base station and the signal decoded at its own station, or selects the signal with higher line quality, and then sends the signal to the next base station. The line quality of the signal between base stations improves each time the signal passes through the base station, and the line quality of the signal between the base stations improves each time it passes through the base station. A base station reception method characterized by extracting good reception information. (2) The connection between the base stations is made into a loop so that the information received from the mobile device continues to circulate within this loop, and each base station transfers the information received from the mobile device received by its own station and the information received from the previous base station. By comparing the received information from the mobile device and performing signal synthesis or signal selection, the quality of the received information from the mobile device is improved and transferred to the next base station. By repeating this process, the base station The base according to claim 1, characterized in that the quality of the information is improved each time it passes through the base, and when the quality of the received information exceeds a certain value, the received information is extracted from this loop and used as information from the mobile device. Station reception method. (3) When coded signals are used as signals between mobile base stations, maximum likelihood decoding is performed once at the base station as a method of transmitting quality information of information received from the mobile station between connected base stations. By re-encoding the signal again using the signal and multiplying this re-encoded signal by the likelihood obtained during decoding, the received signal from the mobile device has a likelihood that is quality information of the information received from the mobile device. 3. The base station reception system according to claim 2, wherein a new signal is generated and this signal is transferred to the next base station.