JP2005039719A - Communication base station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication base station capable of always selecting an appropriate communication channel. <P>SOLUTION: In the communication base station, it is equipped with a measurement information input part which inputs the respective measurement results of a received radio field strength measurement means and a radio interference measurement means in a fuzzy inference engine part and a selection means for selecting one communication channel from among a plurality of communication channels according to a fuzzy inference result which the fuzzy inference engine part outputs by fuzzy inference based on the inputted measurement results and the appropriate communication channel is selected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for selecting an optimal communication channel using fuzzy theory in a mobile station and a base station that perform wireless communication.

  One common radiotelephone system is a cellular radiotelephone system. In order to realize a cellular radiotelephone system, first, a wide area is subdivided. The subdivided area is called a cell, and a fixed station (hereinafter referred to as “base station”) that covers the cell in radio waves is installed. In addition, an exchange that connects a plurality of base stations and manages them in an integrated manner is installed. In this way, a wide range can be covered by setting a plurality of cells. In addition, the exchange is connected to an existing telephone line network, the Internet network, etc., and can communicate with a telephone, a data server, and the like.

  Such a system is also used in PHS and wireless LAN. A voice or data communication service is provided to the radio telephone through the fixed station and the exchange. Hereinafter, the wireless telephone will be described as a mobile station, and the fixed station will be described as a base station. A method of selecting a communication channel in conventional wireless communication will be described with reference to (Table 1), (Table 2), (Table 3), (Table 4), (Table 5), FIG. 1 and FIG.

  In order to select the best channel from among a plurality of communication channels, the base station always measures the interference radio wave intensity in units of channels. (Table 1) shows the interference radio wave intensity in the uplink direction (hereinafter “uplink”) and downlink direction (hereinafter “downlink”) of the communication channel that can be allocated by the base station, The correlation of the transmission power permitted to be transmitted from the base station is shown. The jamming field intensity is described as Rx level on the uplink side and Tx level on the downlink side.

  Table 2 shows the received radio wave intensity from the mobile station received by the base station on the uplink of the control channel. Table 3 shows thresholds for determining the base station / mobile station distance based on the uplink control channel received radio wave intensity.

  Referring to FIG. 1, the received radio wave intensity 121 of the uplink control channel received from the mobile station 101 close to the base station 110 is greater than the received radio wave intensity 120 of the uplink control channel received from the mobile station 100 far from the base station 110. Is also known to be strong. Based on the relationship between the base station and the mobile station, the received radio wave is strong = close to the distance, the received radio wave is weak = the distance is far, and a threshold is set for the received radio wave strength of the uplink control channel from the base station. Judging near / far.

  In (Table 3), the radio field intensity received on the uplink of the control channel is not less than the value defined as the base station-mobile station distance determination threshold as shown in pattern 1 of (Table 2). If there is, it can be determined in decision 201 that the radio wave intensity from the mobile station received on the uplink is strong, so that the mobile station exists in the vicinity of the base station. Therefore, at 202, the downlink transmission output is determined as the small transmission output. Further, since the downlink transmission output from the base station is set to a small output, 203 is used in which the channel with the smallest Tx level is selected at the place where the interference on the downlink side is the smallest, that is, in (Table 1). . In this case, the channel selection result shown in pattern 1 of (Table 5) is obtained.

  On the other hand, if the radio field intensity received on the uplink control channel is smaller than the value defined as the base station-mobile station distance determination threshold value as shown in pattern 2 of (Table 2), determination 201 is performed. , It is determined that the mobile station exists far from the base station. Therefore, at 204, the downlink transmission output is determined as the large transmission output. In addition, since the downlink transmission output from the base station is set to a high output, 205 is used where the channel with the smallest Rx level is selected where the interference on the uplink side is the smallest, that is, in (Table 1). In this case, the channel selection result shown in pattern 2 of (Table 5) is obtained.

The cited document relates to the use of fuzzy theory to control handover in a cellular telephone network and includes receiving a fuzzy inference engine input and determining the call to be handed over Techniques that apply to a predetermined set of rules are disclosed.
JP-A-11-286573

  However, in this case, since the mechanism for changing the logic for selecting the communication channel with the threshold as the boundary is defined by Crisp logic, does it cross the threshold boundary? Thus, the selection logic changes completely.

Here, the crisp logic is a clear binary logic whether the value belongs to or does not belong to a set, and has the property that there is no boundary ambiguity while it is difficult to make an intermediate judgment. have. For this reason, the application of the logic for selection does not change even when the received radio wave intensity of the uplink is slightly different in the vicinity of the threshold value or when it is far from the threshold value.

Uplink control channel received signal strength 41 dB ⇒ Pattern 1 in (Table 5)
Uplink control channel received signal strength 39 dB ⇒ Pattern 2 in (Table 5)
As described above, in the conventional fuzzy control, even if the received radio wave intensity of the uplink differs by only 2 dB across the threshold, the channel selection logic is the same as when the difference from the threshold is large (Table 2). Applied.

  In other words, in the conventional fuzzy control, suddenly changing the logic for selecting a communication channel with a threshold as a boundary causes a sudden change in the quality of the communication channel near the threshold from the viewpoint of call quality. It was difficult to obtain a favorable selection result.

  In order to solve the above problem, the present invention provides a receiving means for receiving a control channel signal from a mobile station, a transmitting means for transmitting a control channel signal, and a received radio wave for measuring the radio field intensity of the received control channel signal. Intensity measurement means, transmission radio field intensity measurement means for measuring radio field intensity of the transmitted control channel signal, interference radio field intensity measurement means for measuring interference radio field intensity of a communication channel for communicating with the mobile station, and predetermined fuzzy A fuzzy inference engine unit that applies an inference rule to perform fuzzy inference, and a measurement that inputs each measurement result of the received radio wave intensity measuring unit, the transmitted radio wave intensity measuring unit, and the jamming radio wave measuring unit to the fuzzy inference engine unit The information input unit and the fuzzy inference engine unit output the fuzzy inference based on the input measurement result. According inference result, and the configuration and a selection means for selecting one communication channel from among the plurality of communication channels.

  An object of the present invention is to provide a communication base station that can always select an optimal communication channel.

  As described above, in the present invention, the receiving means for receiving the control channel signal from the mobile station, the transmitting means for transmitting the control channel signal, and the received radio field intensity measuring means for measuring the radio field intensity of the received control channel signal. A jamming signal strength measuring means for measuring a jamming signal strength of a communication channel for communicating with the mobile station, a fuzzy reasoning engine unit for executing fuzzy reasoning by applying a predetermined fuzzy reasoning rule, and the received signal strength A measurement information input unit that inputs each measurement result of the measurement unit and the interference radio wave measurement unit to the fuzzy inference engine unit, and a fuzzy inference result output by the fuzzy inference engine unit based on the input measurement result. And selecting means for selecting one communication channel from the plurality of communication channels. By this configuration, the base station fuzzifies the threshold judgment used in selecting the current communication channel, and by comprehensively judging information that is different in a plurality of inputted scales, the base station An optimal communication channel can be selected.

  Further, in the communication base station of the present invention, the fuzzy inference engine unit has a fuzzy inference rule changing means for changing the fuzzy inference rule, so that it is easy to add and delete fuzzy inference elements. Therefore, the base station can select an optimal communication channel.

Further, in the communication base station of the present invention, the fuzzy inference engine unit inputs a fuzzy inference result obtained by fuzzy inference having a predetermined rule into a fuzzy inference having a further different rule, thereby providing a more accurate fuzzy inference. Inference is possible, and an appropriate communication channel can be selected.

  Further, in the communication base station of the present invention, the base station further includes a line control unit, and the line control unit executes a call with the mobile station using the communication channel captured by the communication control unit. Can select the optimum communication channel.

  Further, in the communication base station of the present invention, the fuzzy inference engine unit dynamically adjusts the multiple fuzzy inference rules by feeding back the inference result to the fuzzy inference engine unit via the fuzzy inference rule changing unit. Therefore, the base station can select an optimal communication channel.

  In addition, in the communication base station of the present invention, the means for setting the radio wave output transmitted from the base station can set the optimal transmission output for the communication channel.

  The invention according to claim 1 of the present invention is a receiving means for receiving a control channel signal from a mobile station, a transmitting means for transmitting a control channel signal, and a received radio wave for measuring the radio field intensity of the received control channel signal. Applying a predetermined fuzzy inference rule, intensity measuring means, means for changing the intensity of the radio wave transmitted from the base station, interference radio wave intensity measuring means for measuring the interference radio wave intensity of the communication channel for communicating with the mobile station, and A fuzzy inference engine unit that executes fuzzy inference, a measurement information input unit that inputs each measurement result of the received radio wave intensity measuring unit, the transmitted radio wave intensity measuring unit, and the jamming radio wave measuring unit to the fuzzy inference engine unit; According to the fuzzy inference result output by the fuzzy inference engine unit based on the input measurement result, By providing a selection means for selecting one communication channel from among the communication channel, by a slight change in radio conditions, without changing the communication channel frequently, always suitable traffic channel can be selected.

  According to a second aspect of the present invention, in the communication base station according to the first aspect, the fuzzy inference engine unit includes fuzzy inference rule changing means for changing the fuzzy inference rule, so that the inference rule is changed. Yes, you can always select a more appropriate call channel.

  The invention according to claim 3 of the present invention differs by inputting the fuzzy inference result obtained by fuzzy inference having a predetermined rule into the fuzzy inference having further different rules in the communication base station of claim 1. An inference result by fuzzy reasoning with rule weighting is obtained.

  According to a fourth aspect of the present invention, in the communication base station of the first aspect, the communication base station further includes a line control unit, and the line control unit is connected to the mobile station by a communication channel captured by the communication control unit. Therefore, it is possible to select a communication channel without causing a significant change in the selection rule near the threshold value.

  According to a fifth aspect of the present invention, in the communication base station according to the first aspect, the fuzzy inference engine unit automatically feeds back the inference result to the fuzzy inference engine unit via the fuzzy inference rule changing unit. Tune the rules of fuzzy reasoning.

The invention according to claim 6 of the present invention is a receiving means for receiving a control channel signal from a mobile station, a transmitting means for transmitting a control channel signal, and a received radio wave for measuring the radio field intensity of the received control channel signal. Applying a predetermined fuzzy inference rule, strength measuring means, means for setting the radio field intensity transmitted from the base station, jamming radio field intensity measuring means for measuring the jamming radio field intensity of the communication channel for communicating with the mobile station, and A fuzzy inference engine unit that executes fuzzy inference, a measurement information input unit that inputs each measurement result of the received radio wave intensity measuring unit and the jamming radio wave measuring unit to the fuzzy inference engine unit, and the fuzzy inference engine unit One of the communication channels is selected according to the fuzzy inference result output by fuzzy inference based on the input measurement result. A communication base station having a selection means for selecting a communication channel, and the base station constantly transmits the optimum communication channel to the appropriate call channel without frequently changing the communication channel due to slight changes in radio wave conditions. Output radio wave transmission intensity can be set.

  According to a seventh aspect of the present invention, in the communication base station of the sixth aspect, the fuzzy inference engine unit has fuzzy inference rule changing means for changing the fuzzy inference rule, so that the inference rule is changed. Yes, you can always select a more appropriate call channel.

  The invention according to claim 8 of the present invention differs in that, in the communication base station of claim 6, fuzzy inference results obtained by fuzzy inference having a predetermined rule are input to fuzzy inference having further different rules. An inference result by fuzzy reasoning with rule weighting is obtained.

  According to a ninth aspect of the present invention, in the communication base station according to the sixth aspect, the communication base station further includes a line control unit, and the line control unit is connected to the mobile station by a communication channel captured by the communication control unit. Therefore, it is possible to select a communication channel without causing a significant change in the selection rule near the threshold value.

  According to a tenth aspect of the present invention, in the communication base station according to the sixth aspect, the fuzzy inference engine unit automatically feeds back the inference result to the fuzzy inference engine unit via the fuzzy inference rule changing unit. Tune the rules of fuzzy reasoning.

  FIG. 3 is a block diagram showing a configuration of a base station to which an embodiment of the present invention is applied, and FIG. 4 is a conceptual diagram of multiple multistage fuzzy inference to which an embodiment of the present invention is applied. FIG. 5 is a block diagram showing a fuzzy inference engine unit and multiple fuzzy rules to which an embodiment of the present invention is applied, and FIG. 6 is a conceptual diagram regarding tuning of fuzzy rules.

  In FIG. 3, reference numeral 301 denotes a base station antenna as a receiving means for receiving various signals from a plurality of mobile stations used for transmitting / receiving radio signals to / from a mobile station and measuring Tx level and Rx level. A control channel received radio wave intensity measuring unit as means for measuring the received radio wave intensity of the received uplink control channel, 303 is a received interference wave intensity (Rx level) measuring unit as means for measuring the Rx level, and 304 is Tx. Transmitter interference wave intensity (Tx level) measuring unit as means for measuring the level, 306 is a fuzzy inference engine unit using fuzzy inference, 305 is a control channel received radio wave intensity measuring unit 302, and received interference wave intensity (Rx level). Various radio wave intensities measured by the measurement unit 303 and the transmission interference wave intensity (Tx level) measurement unit 304 are converted into fuzzy inference inputs. An information input unit 310 for inputting to the input unit 306, 310 a fuzzy inference rule changing unit for correcting (including addition, deletion, etc.) fuzzy inference rules of the fuzzy inference engine unit 306, and 309 obtained by the fuzzy inference engine unit 306 A channel selection unit that performs channel selection based on the fuzzy inference result, 307 is a communication control unit that transmits / receives control channel information and communication channel information to / from a mobile station via a receiving unit, and 308 communicates with a communication control unit on the wireless side. A line control unit that performs line control with the network side. The communication control unit 307 includes a changing unit that changes the intensity of the transmission radio wave. Further, the reception interference wave intensity (Rx level) measurement unit 303 and the transmission interference wave intensity (Tx level) measurement unit 304 are combined to serve as reception radio wave intensity measurement means.

  In FIG. 4, 401 is an input to multiple multistage fuzzy inference, and 402, 403, and 404 are multiple fuzzy inference rules.

  Reference numeral 405 denotes the result of multiple multistage fuzzy inference. Multiple multi-stage fuzzy inference has the advantage that it can be ruled and modeled with linguistic connections for the association of different scales. For example, in the financial market, if the money supply goes up, the amount of money that goes to the financial market increases, so the interest rate when a bank borrows money from the BOJ decreases. Since banks can raise funds at low interest rates, they can lend to companies at low interest rates. Companies that have been able to borrow money at low interest rates can make multiple multi-stage fuzzy relatively easily by multiplying multiple fuzzy inference results by increasing capital investment and increasing employment. Modeling can be realized as inference. Multiple multi-stage fuzzy inference is advantageous when it is difficult to directly relate from the money supply to the increase in employment, and when the inference result is different from the input one. Also in this embodiment, the distance between the base station and the mobile station inferred from the received radio field intensity of the control channel and the intensity of the measured interfering radio wave are different in scale, but by using multiple multistage fuzzy inference, A conclusion on the scale of “ease of reach” can be obtained.

  Regarding the base station configured as described above, first, the operation of the fuzzy inference engine unit in selecting a communication channel will be described with reference to FIG. The detailed contents of the fuzzy inference engine unit 306 are shown in FIG. 501 to 507 shown in FIG. 5B are defined as fuzzy inference elements constituting the fuzzy inference engine unit. The behavior of fuzzy inference elements is defined by multiple fuzzy inference rules. Reference numerals 531 to 537 in FIG. 5A are details of the multiple fuzzy inference rules 501 to 507 shown in FIG. The logical expression 541 is a logical expression for evaluating the quality of the channel.

  FIG. 5B will be described in order from the input. Information input to the fuzzy inference engine unit 306 includes Rx levels measured at Tx levels 515 and 303 measured by control channel received radio wave strengths 511 and 304 measured by the control channel received radio wave strength measuring unit 302. 514. On the other hand, as the output of the fuzzy inference engine, two pieces of information of the transmission radio wave output 520 and the channel quality 521 are output.

  First, the radio wave intensity 511 is input to the fuzzy inference element 501. The multi-fuzzy inference rule 501 is defined by the rule 531, and fuzzy inference results 512 and 513 (512 and 513 are the same value) related to the distance between the base station and the mobile station are determined by the control channel received radio wave intensity. The fuzzy inference result regarding the distance is further input as 512 and 513 to the fuzzy inference elements 502 and 503 in the next stage. In this way, an inference form in which fuzzy inference elements defined by the multiple fuzzy inference rules are connected in multiple stages is called multiple multistage fuzzy inference.

  A conceptual diagram of multiple multistage fuzzy inference is shown in FIG. With respect to the input 401, the inference result derived by the multiple fuzzy inference rule 402 is further input to the multiple fuzzy inference rule 403, and this is repeated to derive a multiple multistage fuzzy inference result 405.

512 is further input to 502 (multiple fuzzy inference rule 532), and a fuzzy inference result 516 indicating the ease of transmission radio waves is derived. Further, since the reachability of the transmission radio wave is also obtained from the inference result of 503 (multiple fuzzy inference rule 533) input with the Tx level 515, the fuzzy inference of 502 and 503 is performed in the ease of transmission radio wave reachability fuzzy synthesis processing 510. The results are synthesized and input to the next stage fuzzy inference element 504. As a result of input to the rule 504, a transmission radio wave output 520, which is one of the outputs of the fuzzy inference engine unit, can be derived. Further, the output 520 is further input to the rule 507 (multiple fuzzy inference rule 537), thereby deriving a weighting 519 indicating how much importance is attached to the reachability of the transmitted radio wave and the reachability of the received radio wave.

  Similarly, the distance 513 is input to the rule 505 (multiple fuzzy inference rule 533), and the easiness of reaching the radio wave received by the base station from the mobile station is derived as the fuzzy inference result. In addition, the easiness of reaching the radio wave received by the base station from the mobile station is derived as the fuzzy inference result by the rule 506 (multiple fuzzy inference rule 536) to which the Rx level 514 is input. In processing 509, they are combined to derive the reachability 517 of the received radio wave, which is the fuzzy inference result.

  518 and 519, which are the reachability of transmission radio waves equivalent to 517 and 516 (for input of the evaluation formula A), are input to the channel quality evaluation formula 508 (logical formula details 541), and another fuzzy inference engine The channel quality 521, which is the output of, is derived.

  The above processing is executed for all channels, and the channel selection unit 309 compares the output 521 of the fuzzy inference engine unit 306 to select the best channel as a communication channel.

  In the present embodiment, in the fuzzy inference engine unit, as long as the input conditions necessary for the output of the fuzzy inference engine unit can be secured, the fuzzy inference elements and input conditions are basically freely deleted via the fuzzy inference rule changing unit 310. It is possible. For example, if the distance between the base station and the mobile station is not taken into consideration as a condition for deriving the reachability 516 of the transmission radio wave, the fuzzy inference elements 501 and 502 and the input 511 can be deleted. In such a case, even if the fuzzy inference element is deleted via the fuzzy inference rule changing unit 310, it is only necessary to secure an input necessary for deriving a conclusion.

  A mechanism for tuning multiple fuzzy inference rules by applying feedback to the fuzzy inference result in this embodiment will be described with reference to FIG. Here, a fuzzy reasoning element 507 (multiple fuzzy reasoning rule 537) that performs fuzzy reasoning regarding transmission and reception weighting will be described. FIG. 6A shows a multiple fuzzy inference rule 537. It consists of a fuzzy membership 601 that indicates the degree of emphasis on the reachability of received radio waves, and a fuzzy membership 602 that indicates the degree of emphasis on the reachability of transmission radio waves. When the fuzzy tuning rule 631 shown in FIG. 6D is applied, the tuning shown in FIGS. 6B and 6C is performed. First, FIG. 6B will be described. When a communication failure occurs in the reception system, it is assumed that the quality in reception has been neglected, and the width of the fuzzy membership 604 is narrowed to increase the ratio of 603 indicating the importance of the ease of arrival of received radio waves. I do. Conversely, when a communication failure occurs in the transmission system, it is considered that transmission quality is neglected, and by reducing the width as in fuzzy membership 605, the degree of emphasis on the reachability of transmission radio waves is increased. Processing for increasing the ratio of 606 shown is performed. This makes it possible to dynamically set the optimal fuzzy rule by always tuning the fuzzy inference rule.

  The present invention achieves a smooth communication mode between a mobile station and a base station by selecting an optimal communication channel using fuzzy theory in a radio communication technique, particularly in a mobile station and a base station.

The schematic diagram which shows the relationship between the radio field intensity and distance of one Example of this invention A flowchart showing a channel selection processing method of the current base station The block diagram which shows the structure of a base station in one Example of this invention. Conceptual diagram showing the concept of multiple multistage fuzzy inference The block diagram which shows the structure of the fuzzy inference engine in one Example of this invention. The conceptual diagram which shows the tuning concept of a multiple fuzzy inference rule in one Example of this invention

Explanation of symbols

301 Base Station Antenna 302 Control Channel Received Radio Wave Strength Measurement Unit 303 Received Interference Wave Strength (Rx Level) Measurement Unit 304 Transmission Interference Wave Strength (Tx Level) Measurement Unit 305 Information Input Unit 306 Fuzzy Inference Engine Unit 307 Communication Control Unit 308 Line Control Section 309 Channel selection section 310 Fuzzy inference rule change section 401 Input to multiple multistage fuzzy inference 402 First stage multiple fuzzy inference rule 403 Second stage multiple fuzzy inference rule 404 nth stage multiple fuzzy inference rule 405 n stage multiple fuzzy inference result

Claims (10)

Receiving means for receiving a control channel signal from a mobile station;
A transmission means for transmitting a control channel signal;
Received radio field intensity measuring means for measuring the radio field intensity of the received control channel signal;
A jamming signal strength measuring means for measuring a jamming signal strength of a communication channel for communicating with the mobile station;
A fuzzy inference engine unit for executing fuzzy inference by applying predetermined fuzzy inference rules;
A measurement information input unit for inputting the measurement results of the received radio wave intensity measuring unit and the jamming radio wave measuring unit to the fuzzy inference engine unit;
Selecting means for selecting one communication channel from the plurality of communication channels according to the fuzzy inference result output by the fuzzy inference engine unit based on the input measurement result. Communication base station. The communication base station according to claim 1, wherein the fuzzy inference engine unit includes fuzzy inference rule changing means for changing the fuzzy inference rule. 2. The communication base station according to claim 1, wherein the fuzzy inference engine unit inputs a fuzzy inference result obtained by fuzzy inference having a predetermined rule into a fuzzy inference having further different rules. . 2. The communication base station according to claim 1, further comprising a line control unit, wherein the line control unit executes a call with a mobile station using a communication channel captured by the communication control unit. base station. The communication base station according to claim 1, wherein the fuzzy inference engine unit feeds back an inference result to the fuzzy inference engine unit via a fuzzy inference rule changing unit. Receiving means for receiving a control channel signal from a mobile station;
A transmission means for transmitting a control channel signal;
Received radio field intensity measuring means for measuring the radio field intensity of the received control channel signal;
Means for setting the radio field intensity transmitted from the base station;
A jamming signal strength measuring means for measuring a jamming signal strength of a communication channel for communicating with the mobile station;
A fuzzy inference engine unit for executing fuzzy inference by applying predetermined fuzzy inference rules;
A measurement information input unit for inputting the measurement results of the received radio wave intensity measuring unit and the jamming radio wave measuring unit to the fuzzy inference engine unit;
Selecting means for selecting one communication channel from the plurality of communication channels according to the fuzzy inference result output by the fuzzy inference engine unit based on the input measurement result. Communication base station. The communication base station according to claim 6, wherein the fuzzy inference engine unit includes fuzzy inference rule changing means for changing the fuzzy inference rule. 7. The communication base station according to claim 6, wherein the fuzzy inference engine unit inputs a fuzzy inference result obtained by fuzzy inference having a predetermined rule into a fuzzy inference having a different rule. . 7. The communication base station according to claim 6, further comprising a line control unit, wherein the line control unit executes a call with a mobile station using a communication channel captured by the communication control unit. base station. The communication base station according to claim 6, wherein the fuzzy inference engine unit feeds back an inference result to the fuzzy inference engine unit via a fuzzy inference rule changing unit.

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