CN1734973B - Communication device and control method thereof - Google Patents

Abstract

To provide a communication apparatus capable of performing highly reliable communication by effectively utilizing antenna resources and a method for controlling the communication apparatus. The communication apparatus comprises: a plurality of antennas 12-1 to 12-8; a plurality of radio communication parts 16-1, 16-2; a control part 26 for determining the number of antennas 12 to be connected to the respective radio communication parts 16-1, 16-2; and an antenna switching part 14 for connecting the respective antennas 12-1 to 12-8 to either one of the radio communication parts 16-1, 16-2.

Description

Communication device and control method thereof

technical field

The present invention relates to a communication device and its control method, especially a communication device with multiple wireless communication units and multiple antennas and its control method.

Background technique

FIG. 8 shows the configuration of a base station of a conventional PHS (Personal Handyphone System: Personal Handyphone System). As shown in the figure, in the conventional configuration, a plurality of wireless communication units 106-1, 106-2 are provided, and four antennas are connected to each of the wireless communication units 106-1, 106-2. Each wireless communication unit 106 has a transmission unit 100 , a reception unit 104 , and a PLL circuit 102 , and data transmitted by the transmission unit 100 of each wireless communication unit 106 is externally acquired by the baseband processing unit 108 through the interface unit 110 . Also, the data received by the receiving unit 104 of each wireless communication unit 106 is supplied to the baseband processing unit 108 and supplied to the outside through the interface unit 110 . In addition, the control unit 112 operates using the storage device 114 and simultaneously controls the baseband processing unit 108 and each wireless communication unit 106 .

In general, the larger the number of antennas, the more reliable communication can be performed by each wireless communication unit 106 . On the other hand, depending on the communication status of the wireless communication unit 106, even if the wireless communication unit 106 does not use all four antennas, it may be possible to perform communication with sufficient reliability. Therefore, in such a case, by connecting part or all of the antennas connected to one wireless communication unit 106 to the other wireless communication unit 106, the other wireless communication unit 106 can also perform More reliable communication. However, in the conventional configuration, since the number of antennas connected to each wireless communication unit 106 is fixed, there is a problem that such flexible use of antennas cannot be realized.

[Patent Document 1] JP-A-2003-134018

Contents of the invention

The present invention has been made in view of the above problems, and an object of the present invention is to provide a communication device and a control method thereof capable of performing highly reliable communication by effectively utilizing antenna resources.

In order to solve the above-mentioned problems, the communication device in the present invention is characterized in that it includes: a plurality of antennas; a plurality of wireless communication units; a control unit that determines the number of antennas connected to each of the wireless communication units; and, the antenna A switching unit connects each of the antennas to any one of the plurality of wireless communication units based on a decision made by the control unit.

According to the present invention, since an antenna switching unit is provided, and each antenna is connected to any one of a plurality of wireless communication units according to a decision made by the control unit, antenna resources can be effectively utilized, and overall reliable communication can be performed. communication.

In addition, it is preferable that the plurality of wireless communication units communicate using different frequencies. In addition, the plurality of wireless communication units may respectively use the antennas connected to the wireless communication units to perform communication in space diversity or adaptive array. In this way, each wireless communication unit can perform highly reliable communication corresponding to the number of antennas.

In addition, the control unit may determine the number of antennas connected to each wireless communication unit based on the number of communication partners of each wireless communication unit. In this way, when the number of communication partners of the wireless communication unit is small, the number of antennas is not allocated to the wireless communication unit in vain. In addition, multiple antennas can be assigned to one communication target, enabling high-quality communication.

In addition, each of the wireless communication units may also communicate in a time-division multiplexing manner, and the time slots of the wireless communication units are synchronized, and the control unit may, according to the time slots of the wireless communication units The signal-to-noise ratio (S/N ratio) determines the number of antennas connected to each of the wireless communication units. In this case, each wireless communication unit preferably includes at least a receiving unit. In this way, the number of antennas can be determined according to the signal-to-noise ratio, that is, the stability and difficulty of the current communication. At this time, the control unit may determine the number of the antennas connected to each wireless communication unit based on a difference in signal-to-noise ratio for each time slot of each wireless communication unit.

In addition, each of the wireless communication units may also communicate in a time-division multiplexing manner, and the time slots of the wireless communication units are synchronized, and the control unit may, according to the time slots of the wireless communication units The difference in the communication rate of each wireless communication unit determines the number of the antennas connected to each of the wireless communication units. In this manner, in each wireless communication unit, it is possible to realize reliable communication necessary or desired for each communication rate.

In addition, the control unit may determine the number of antennas required based on the communication rate and signal-to-noise ratio of each wireless communication unit, and determine the number of antennas connected to each wireless communication unit according to the determination result. . In this way, the number of antennas connected to each wireless communication unit can be determined so as not to fall below, for example, the number of required antennas (referring to the necessary minimum number of antennas).

In this case, the control unit may include: according to the current signal-to-noise ratio of each wireless communication unit and the number of antennas currently connected to each wireless communication unit, controlling the A module for predicting the signal-to-noise ratio after the number of antennas in the department is changed to a given number, and judging the number of required antennas according to the prediction result. In this case, the number of antennas for each of the wireless communication units may be changed to the predetermined number based on a comparison between the predicted SNR and the desired SNR (necessary minimum SNR). Quantity is limited.

In this case, the control unit may further include: a module for determining the above-mentioned required signal-to-noise ratio based on the communication rates of the wireless communication units. The minimum signal-to-noise ratio necessary to achieve the communication rate can thus be ensured as much as possible.

In addition, the control unit may change the communication rate of each wireless communication unit based on a comparison between the signal-to-noise ratio of each wireless communication unit and a desired signal-to-noise ratio. In this way, the necessary communication reliability is ensured even in the event that the signal-to-noise ratio is lower than the desired signal-to-noise ratio.

In addition, the control method of the communication device in the present invention is a control method of a communication device including a plurality of antennas and a plurality of wireless communication units, characterized in that the control unit determines the antenna connected to each of the wireless communication units. and according to the determination, connect each of the antennas to any one of the plurality of wireless communication units. In this way, antenna resources can be effectively utilized, thereby realizing highly reliable communication as a whole.

Description of drawings:

FIG. 1 is a diagram showing the configuration of a communication device in an embodiment of the present invention.

FIG. 2 is a flowchart showing antenna selection processing of the communication device according to the embodiment of the present invention.

FIG. 3 is a detailed flowchart of antenna switching judgment processing.

FIG. 4 is a detailed flowchart of antenna switching judgment processing.

Fig. 5 is a diagram showing a required S/N ratio determination table.

Fig. 6 is a diagram showing a S/N ratio variation table.

FIG. 7 is a diagram showing the configuration of a communication device in another embodiment of the present invention.

FIG. 8 is a diagram showing a conventional communication device (PHS base station).

In the figure: 10, 10a-communication device (PHS base station), 12-antenna, 14-antenna switching part, 16, 16a-wireless communication part, 18-transmitting part, 20-PLL (Phase Lock Loop: phase locked loop) circuit , 22-receiving unit, 24-baseband processing unit, 26-control unit, 28-storage device, 30-interface unit.

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a communication device in an embodiment of the present invention. The communication device 10 shown in this figure includes antennas 12-1 to 12-8; wireless communication units 16-1 and 16-2; antenna switching unit 14; baseband processing unit 24; control unit 26; storage device 28; 30 to make up. In addition, each wireless communication unit 16 includes a transmission unit 18 , a PLL circuit 20 , and a reception unit 22 .

All of the eight antennas 12-1 to 12-8 are connected to the antenna switching unit 14, and to the antenna switching unit 14, wireless communication units 16-1 and 16-2 are also connected. Furthermore, the antenna switching unit 14 connects a part of the antennas 12-1 to 12-8 to the wireless communication unit 16-1 in accordance with the antenna switching signal output from the control unit 26, and connects the remaining part to the wireless communication unit 16-1. 2 connections. The above-mentioned antenna switching signal is, for example, a signal indicating the number of antennas to be connected to the wireless communication unit 16-1, and a signal specifying which wireless communication unit 16 how many antennas 12 should be connected.

The communication device 10 is configured as a PHS base station, and performs communication in a TDMA/TDD (Time Division Multiplex/Time Division Duplex) system with a plurality of wireless terminals not shown in the figure as communication targets. Also, the communication device 10 can perform communication by selectively applying a plurality of multilevel modulation schemes (BPSK, QPSK, 8PSK, 16QAM, 32QAM, and 64QAM) with different communication rates (information transmission rates) in each slot. Also, when a plurality of antennas 12 are connected to one wireless communication unit 16, communication is performed using space diversity or an adaptive array method. In each wireless communication unit 16 , the transmitting unit 18 converts the baseband signal supplied from the baseband processing unit 24 into a carrier wave using the supplied signal from the PLL circuit 20 , and transmits it through the antenna 12 connected to the antenna switching unit 14 . In addition, each wireless communication unit 16 converts a signal received by the antenna 12 connected by the antenna switching unit 14 into a baseband signal using the supplied signal from the PLL circuit 20 , and supplies it to the baseband processing unit 24 .

The baseband processing unit 24 is connected to the network side through the interface unit 30 so as to be able to send and receive communication content with the network side. In addition, the baseband processing unit 24 assigns a call from each wireless terminal to an arbitrary time slot of an arbitrary wireless communication unit 16 according to an instruction from the control unit 26 . At this time, the time slots of the wireless communication units 16 are synchronized, and the start period and end time of each time slot of the wireless communication unit 16-1 coincide with the start time and end time of each time slot of the wireless communication unit 16-2.

The control unit 26 is composed mainly of a microprocessor, operates using a storage device 28 composed mainly of a RAM and the like, and controls the communication device 10 as a whole. In particular, the control unit 26 acquires the S/N ratio of each slot of each wireless communication unit 16 from the baseband processing unit 24 . In addition, the control unit 26 manages the communication rate (modulation method) of each call, and uses this information to determine how many antennas 12 should be connected to each wireless communication unit 16 in each time slot of each wireless communication unit 16 . Then, an antenna switching signal is generated according to the determination, and is supplied to the antenna switching unit 14 every slot.

That is, each wireless communication unit 16 performs communication of a call assigned by the control unit 26 in each time slot, and the communication rate thereof is managed by the control unit 26 in accordance with an instruction from the baseband processing unit 24 . Then, in each slot, the S/N ratio and the communication rate of the communication performed by each wireless communication unit 16 are acquired, and an antenna switching signal is generated based on these information. In addition, the control unit 26 manages the number of calls allocated to each wireless communication unit 16, and generates an antenna switching signal based on the number of calls.

Specifically, if the number of calls assigned to one wireless communication unit 16 is zero, an antenna switching signal is generated to assign all antennas 12 to the other wireless communication unit 16 . In this way, the antenna 12 is not assigned to the wireless communication unit 16 to which the number of assigned calls is zero.

In addition, in each time slot, if the difference in the S/N ratio of the communication performed by each wireless communication unit 16 is larger than a predetermined value, the number of antennas connected to the wireless communication unit 16 that is performing communication with a large S/N ratio is reduced. The number of antennas 12 is 12, and the number of antennas 12 connected to the wireless communication unit 16 performing communication with a small S/N ratio is increased accordingly. At this time, the number of reductions of the antennas 12 of the wireless communication unit 16 performing communication with a large S/N ratio, that is, the number of antennas 12 of the wireless communication unit 16 performing communication with a small S/N ratio is changed according to the magnitude of the difference in the S/N ratio. 12 increments. Specifically, the larger the difference in the S/N ratio, the larger the number of reductions/increases.

In addition, in each time slot, the number of antennas 12 connected to the wireless communication unit 16 that performs communication at a high communication rate is reduced according to the difference in the communication rate of the communication performed by each wireless communication unit 16, and the number is increased corresponding to the number. The number of antennas 12 connected to the wireless communication unit 16 with a low communication rate. At this time, the greater the difference in communication rate, the greater the number of reductions/increases of the antenna 12 .

2 to 4 are flowcharts showing processing (antenna selection processing) for determining the number of antennas 12 connected to each wireless communication unit 16 executed in each slot. First, as shown in FIG. 2, the control unit 26 checks for each time slot whether or not the number of calls assigned to any one of the wireless communication units 16 is not zero (S101). Then, if the number of calls allocated to any wireless communication unit 16 is zero, an antenna switching signal is generated so that one antenna 12 is not connected to the wireless communication unit 16 whose number of calls allocated is zero, and All eight antennas 12 are connected to the other wireless communication unit 16, and the antenna switching signal is supplied to the antenna switching unit 14 (S104).

On the other hand, if any one of the wireless communication units 16 is assigned one or more calls, the antenna switching judgment process shown in FIGS. 3 and 4 is performed ( S102 ). In this process, as shown in FIG. 3 , it is first determined whether the communication conditions of the two wireless communication units 16 are equal (S201). Specifically, if the modulation method (communication rate) applied to the baseband signal supplied to each wireless communication section 16 is the same, and the difference in the S/N ratio of the communication performed by each wireless communication section 16 is within 3 dB, it is determined that The communication conditions of the two wireless communication units 16 are equal. Then, if the communication conditions of the two are the same, an antenna switching signal is generated so that the number of antennas of the wireless communication section 16-1 and the wireless communication section 16-2 are the same, and the antenna switching signal is supplied to the antenna switching section 14 (S213 ).

If it is determined in S201 that the communication conditions of the two wireless communication units 16 are not equal, then it is determined whether the S/N ratios of the communications performed by the two wireless communication units 16 are equal (S202). Specifically, when the difference between the two S/N ratios is within 3dB, they are judged to be equal. If it is determined that the differences in S/N ratios are equal, then the magnitude of the difference in communication rates between the two wireless communication units 16 is determined (S203). Specifically, if the difference in communication rate is greater than 8 times, it is determined that the difference in communication rate is large, and the process proceeds to S204. Also, if the difference is less than 8 times and greater than 2 times, it is determined that the difference in communication rate is medium, and the process proceeds to S206. In addition, if the difference is less than 2 times, it is determined that the difference in communication rate is small, and the process proceeds to S207.

In the process of S204, it is determined whether the S/N ratio of the communication performed by both wireless communication units 16 is sufficiently high, specifically, whether it is higher than a required S/N ratio described later. Then, if it is judged to be sufficiently large, an antenna switching signal is generated, and seven antennas 12 are connected to the wireless communication unit 16 performing high communication rate communication, and 1 antenna 12 is connected to the wireless communication unit 16 performing low communication rate communication. antenna 12, and supplies the antenna switching signal to the antenna switching unit 14 (S205). On the other hand, if it is determined that the S/N ratio is not sufficiently large, the process proceeds to S206.

In the process of S206, an antenna switching signal is generated, six antennas 12 are connected to the wireless communication unit 16 performing high communication rate communication, two antennas 12 are connected to the wireless communication unit 16 performing low communication rate communication, and This antenna switching signal is supplied to the antenna switching unit 14 . In addition, in the process of S207, an antenna switching signal is generated, five antennas 12 are connected to the wireless communication unit 16 performing high communication rate communication, and three antennas 12 are connected to the wireless communication unit 16 performing low communication rate communication. , and supply the antenna switching signal to the antenna switching unit 14 .

If it is determined in S202 that the S/N ratios are not equal, then it is determined whether the communication rates in both wireless communication units 16 are equal (S209). Specifically, if the communication rates are the same, it is determined that the communication rates are equal.

If it is determined that the communication rates are equal, it is next determined whether or not the difference in S/N ratio is large. Specifically, if the difference in S/N ratio is 3 dB or more, it is determined that the difference in S/N ratio is large. Then, if the difference in S/N ratio is large, an antenna switching signal is generated, and six antennas 12 are connected to the wireless communication unit 16 communicating with a large S/N ratio, and to the wireless communication unit 16 communicating with a small S/N ratio. The communication unit 16 connects the two antennas 12, and supplies the antenna switching signal to the antenna switching unit 14 (S211). In addition, if it is determined in S210 that the difference in the S/N ratio is small, an antenna switching signal is generated, and five antennas 12 are connected to the wireless communication unit 16 communicating with the large S/N ratio, and to the wireless communication unit 16 communicating with the small S/N ratio. The wireless communication unit 16 performing communication connects the three antennas 12, and supplies the antenna switching signal to the antenna switching unit 14 (S212).

If it is determined in S209 that the communication rates are not equal, then it is judged whether the following three conditions are met (S301), namely: 1) the communication rate of one wireless communication unit 16 is lower than the prescribed communication rate; The communication rate at the wireless communication section 16 is higher than the prescribed communication rate; 3) The S/N ratio of the wireless communication section 16 with the lower communication rate is sufficiently high (greater than the required S/N ratio described later). Then, if all of these three conditions are satisfied, an antenna switching signal is generated, one antenna 12 is connected to the wireless communication unit 16 with a low communication rate, seven antennas 12 are connected to the wireless communication unit 16 with a high communication rate, and the The antenna switching signal is supplied to the antenna switching unit 14 (S305). On the other hand, if it is determined in S301 that the condition is not satisfied, then it is determined whether either the difference in S/N ratio or the difference in communication rate between the two wireless communication units 16 is large (S302). Specifically, if the difference in S/N ratio is 3 dB or more, it is determined that the difference in S/N ratio is large. Also, if one communication rate is twice or more than the other, it is determined that the difference in communication rate is large.

Then, when either the difference in the S/N ratio or the difference in the communication rate is large, an antenna switching signal is generated, and the six antennas 12 are connected to one wireless communication unit 16 and six antennas 12 are connected to the other wireless communication unit 16. Two antennas 12 are connected, and the antenna switching signal is supplied to the antenna switching unit 14 (S304). Specifically, when it is determined in S302 that the difference in the S/N ratio is large, an antenna switching signal is generated, and two antennas 12 are connected to the wireless communication unit 16 communicating with a large S/N ratio, and two antennas 12 are connected to the wireless communication unit 16 communicating with a small S/N ratio. /N ratio The wireless communication unit 16 that communicates is connected to the six antennas 12 and supplies the antenna switching signal to the antenna switching unit 14 . In addition, if it is determined in S302 that the difference in communication rate is large, an antenna switching signal is generated, and the six antennas 12 are connected to the wireless communication unit 16 communicating at a high communication rate, and to the wireless communication unit 16 communicating at a low communication rate. The unit 16 connects the two antennas 12 and supplies the antenna switching signal to the antenna switching unit 14 . On the other hand, when it is determined in S302 that neither the difference in the S/N ratio nor the difference in the communication rate is large, an antenna switching signal is generated, and the same number of antennas 12 are connected to each wireless communication unit 16, and the antennas are switched. The signal is supplied to the antenna switching unit 14 (S303).

After the processing of S205, S206, S207, S211, S212, S213, S303, S304, and S305 is completed, the control unit 26 then changes the communication rate as necessary (S103). That is, when the number of antennas 12 is changed so that the S/N ratio in actual communication becomes lower than the required S/N ratio (minimum S/N ratio), the communication rate for the communication is reduced. Here, the required S/N ratio is determined in advance for each communication rate, and is stored in advance in the storage device 28 as a required S/N ratio table. Fig. 5 shows an example of the required S/N ratio table.

In addition, in S205, S206, S207, S211, S212, S213, S303, S304, and S305, when determining the number of antennas 12 that should be connected to each wireless communication unit 16, it is preferable to determine whether the number exceeds the required antenna number. number. Then, if the required number of antennas is exceeded, the number of antennas 12 connected to each wireless communication unit 16 can be determined as determined in each step. In addition, if the required number of antennas is not exceeded, the number of antennas 12 connected to each wireless communication unit 16 can be limited as determined in each step, for example, the change in the number of antennas 12 itself is limited, or the number of antennas 12 can be suppressed. The amount of change in the number of antennas, or the number of antennas 12 more than the required number of antennas is connected to each wireless communication unit 16 .

The required number of antennas can be determined, for example, as follows. That is, as shown in FIG. 6, a table (S/N ratio change amount table) is stored in the storage device 28 in advance, and this table is for the current number of antennas 12 (the number of antennas (original)) and the number of antennas after the change. Each combination of (switching the number of antennas) is a table showing the amount of change in the S/N ratio due to the change. Then, the required S/N ratio in the current communication rate is read from the required S/N ratio table shown in FIG. 5 . Then, from the S/N ratio change amount table, the change amount of the S/N ratio corresponding to the number of antennas 12 currently connected to each wireless communication unit 16 is read out. Next, based on this value and the current S/N ratio, the predicted values of the S/N ratio when the number of antennas 12 are changed to each number are calculated, and it is judged whether they exceed the above-mentioned required S/N ratio. Then, the smallest number among the number of antennas 12 exceeding the required S/N ratio is set as the required number of antennas. This calculation can be performed every time a predetermined type of event such as a new call occurs, and they can be stored.

Since the communication device 10 according to the above description is provided with the antenna switching unit 14, the control unit 26 provides the antenna switching signal to the antenna switching unit 14 according to the communication rate or the S/N ratio, and can freely control the antennas connected to each wireless communication unit 16. The number of antennas 12 is reduced, so antenna resources can be effectively used and reliable communication can be realized.

In addition, this invention is not limited to the said embodiment. For example, the configuration of the communication device is not limited to that shown in FIG. 1 , and may include four wireless communication units 16a-1 to 16a-4 as in the communication device 10a shown in FIG. It is connected to any one of the wireless communication units 16a through the antenna switching unit 14a. That is, the present invention can be applied regardless of the number of antennas and the number of wireless communication units.

Claims (8)

1. A communication device, characterized in that, comprising: multiple antennas; multiple wireless communications units; The control unit increases or decreases the number of antennas connected to each of the wireless communication units based on the difference in signal-to-noise ratio and the difference in communication rate of the communication of each of the wireless communication units; and, an antenna switching unit that connects at least one of the plurality of wireless communication units to two or more antennas of the plurality of antennas based on a decision made by the control unit, The control unit determines to increase or decrease the number of antennas as the difference in the signal-to-noise ratio or the difference in the communication rate increases. 2. The communication device according to claim 1, wherein: The plurality of wireless communication units communicate using different frequencies. 3. The communication device according to claim 1, wherein: The plurality of wireless communication units perform communication in a space diversity or adaptive array manner using the antennas connected to the wireless communication units, respectively. 4. The communication device according to claim 1, wherein: The control unit determines the number of the antennas connected to each of the wireless communication units based on the number of communication partners of each of the wireless communication units. 5. The communication device according to claim 1, wherein: the control unit, including: changing the number of antennas of each of the wireless communication units to a given number based on the current signal-to-noise ratio of each of the wireless communication units and the number of antennas currently connected to each of the wireless communication units After the signal-to-noise ratio prediction module, And according to the prediction result, the number of required antennas is judged. 6. The communication device according to claim 5, wherein: The control unit further includes: a module for determining a required signal-to-noise ratio according to the communication rate of each of the wireless communication units. 7. The communication device according to claim 1, wherein: The control unit changes the communication rate of each of the wireless communication units based on a comparison of the signal-to-noise ratio of each of the wireless communication units with a desired signal-to-noise ratio. 8. A control method for a communication device comprising a plurality of antennas and a plurality of wireless communication units, characterized in that, including: a determination step of increasing or decreasing the number of the antennas connected to each of the wireless communication units by the control unit according to the difference in the signal-to-noise ratio and the difference in the communication rate of the communication of each of the wireless communication units; and , Based on this determination, the step of connecting at least one of the plurality of wireless communication units to two or more antennas of the plurality of antennas, In the determining step, the greater the difference in the signal-to-noise ratio or the difference in the communication rate, the greater the number of antennas to increase or decrease.

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