JP2008236655A - Communication control method of radio communication apparatus, and radio communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication control method of a radio communication apparatus and the radio communication apparatus capable of effectively increasing the number of multiplexing by an SDMA system while adopting an adaptive modulation system effectively utilizing hardware. <P>SOLUTION: The communication control method is a communication control method of a radio communication apparatus 2 that adopts a space division multi-dimensional connection system and an adaptive modulation system. The method includes an arithmetic operation amount grasping step of grasping the amount of arithmetic operation processing amount of an arithmetic operation processing part 28 for processing transmission/reception data to a user terminal 3; and a modulation class control step for limiting a modulation class determined by the adaptive modulation system for the user terminal 3 during communication when receiving a communication request from a new user terminal 3 in a state where the grasped amount of the arithmetic operation processing exceeds a predetermined value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a communication control method for a wireless communication apparatus that employs a space division multiple access (SDMA) system and an adaptive modulation system, and a wireless communication apparatus that implements the same.

  The SDMA (Spatial Division Multiple Access) method is used in, for example, iBurst (registered trademark), WiMAX (Worldwide Interoperability for Microwave Access), and the like, and is well known. In this type of radio communication base station, a plurality of antennas are used, and the directivity by the plurality of antennas is appropriately controlled according to the user terminal on the user side, so that a plurality of antennas are divided at the same frequency and the same time zone. Communication with the user terminal is enabled.

  On the other hand, as a conventional mobile communication system, in order to improve the communication speed, for example, according to the communication quality represented by FER (Frame Error Rate), SINR (Signal to Noise Ratio), etc., the modulation class (Mod Class ) Is appropriately employed (for example, see Patent Document 1).

JP 2006-14205 A

  By the way, the amount of data transmitted and received by wireless communication increases as the modulation class increases, that is, as the modulation multi-level number increases. Therefore, the amount of calculation processing in hardware such as a DSP (Digital Signal Processor) built in the wireless communication apparatus increases as the modulation class increases.

  For this reason, if the above-described adaptive modulation scheme is simply adopted in a radio communication base station of the SDMA scheme, the amount of data to be transmitted / received increases in a state where a high modulation class is selected, and the time required for data processing of one user terminal is increased. There is a problem that the number of multiple connections (multiplexing number) cannot be increased due to restrictions on the processing capability of hardware.

  As a method for solving this problem, for example, it is conceivable to use hardware capable of higher-speed processing. However, this increases the cost of the base station.

  Accordingly, an object of the present invention made in view of the above point is to provide a communication control method for a wireless communication apparatus and a wireless communication device that can effectively increase the number of multiplexing by the SDMA method while effectively using hardware and adopting an adaptive modulation method. It is to provide a communication device.

The invention according to claim 1, which achieves the above object, is a communication control method for a radio communication apparatus adopting a space division multiple access scheme and an adaptive modulation scheme,
An arithmetic processing amount grasping step for grasping an arithmetic processing amount of an arithmetic processing unit that processes transmission / reception data for the user terminal,
Modulation that limits the modulation class determined by the adaptive modulation scheme for the user terminal in communication when a communication request from a new user terminal is received in a state where the grasped arithmetic processing amount exceeds a predetermined value A class restriction step;
It is characterized by including.

The invention according to claim 2 is the communication control method of the wireless communication apparatus according to claim 1,
In the modulation class limiting step, the modulation class for the user terminal in communication is limited when the number of user terminals in voice communication exceeds a predetermined number.

The invention according to claim 3 is the communication control method of the wireless communication apparatus according to claim 2,
The communication request from the new user terminal is a voice communication request.

The invention according to claim 4 is the communication control method of the wireless communication apparatus according to any one of claims 1 to 3,
The modulation class limiting step is characterized in that the modulation class for each user terminal in communication is limited to be equal to or less than a set value.

The invention according to claim 5 is the communication control method of the wireless communication apparatus according to any one of claims 1 to 3,
In the modulation class limiting step, the modulation class of the user terminal is limited so that the total value of the modulation classes for all user terminals in communication is equal to or less than a predetermined value.

Furthermore, the invention according to claim 6 that achieves the above object is a wireless communication apparatus that employs a space division multiple access scheme and an adaptive modulation scheme,
An arithmetic processing unit for processing transmission / reception data for the user terminal;
An arithmetic processing amount grasping unit for grasping an arithmetic processing amount of the arithmetic processing unit;
A modulation class control unit that controls the modulation class determined by the adaptive modulation method for the user terminal in communication based on the calculation processing amount grasped by the computation processing amount grasping unit;
It is characterized by having.

  According to the present invention, when a communication request from a new user terminal is received in a state where the arithmetic processing amount of the arithmetic processing unit that processes transmission / reception data for the user terminal exceeds a predetermined value, On the other hand, since the modulation class determined by the adaptive modulation scheme is limited, a new user terminal can be spatially multiplexed. Therefore, it is possible to efficiently increase the number of multiplexing by the SDMA method while adopting the adaptive modulation method by effectively using the hardware.

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

(First embodiment)
FIG. 1 shows an example of a mobile communication system using a base station which is a wireless communication apparatus according to the first embodiment of the present invention. The mobile communication system 1 includes a base station 2, a plurality of user terminals 3, and a network 4 connected to the base station 2.

  The base station 2 controls the modulation class of the radio communication with each user terminal 3 by the adaptive modulation method, and can perform multiple communication with the plurality of user terminals 3 by the SDMA method, and can simultaneously communicate at the same frequency and the same time zone. It has become.

  The user terminal 3 is a known mobile phone terminal or PHS terminal used in the communication system. In communication with the base station 2, the user terminal 3 has a modulation class designated by the base station 2 and a voice signal, a packet, etc. Is supposed to send.

  The communication network 4 may be an exchange network of the mobile communication system 1 or may be a TCP / IP network when the mobile communication system 1 is a communication system using an IP telephone.

  FIG. 2 is a functional block diagram showing a configuration of a main part of base station 2 according to the present embodiment. The base station 2 includes a transmission / reception unit 21 having a plurality of antennas 20, a demodulation unit 22, a communication quality acquisition unit 23, a modulation class determination unit 24, a modulation class control unit 25, a modulation unit 26, and a control unit 27. . The control unit 27 is configured to include hardware such as a DSP, and includes an arithmetic processing unit 28 and an arithmetic processing amount grasping unit 29. In FIG. 2, the communication quality acquisition unit 23, the modulation class determination unit 24, and the modulation class control unit 25 are shown separately from the control unit 27 for convenience, but may be configured in the control unit 27.

  Hereinafter, the operation of the base station 2 according to the present embodiment will be described with reference to the flowchart shown in FIG.

  A transmission signal from the user terminal 3 is received by the transmission / reception unit 21 via the plurality of antennas 20 (step S1), the reception signal is demodulated by the demodulation unit 22 (step S2), and supplied to the communication quality acquisition unit 23. At the same time, it is supplied to the control unit 27.

  The communication quality acquisition unit 23 detects the FER and SINR for each user terminal based on the demodulated signal from the demodulation unit 22 to acquire the communication quality (step S3), and uses the acquired communication quality result as the modulation class determination unit. 24, the optimum modulation class corresponding to the communication quality is determined (step S4), and the result is supplied to the modulation class control unit 25.

  On the other hand, in the control unit 27, the arithmetic processing unit 28 decodes the demodulated signal from the demodulating unit 22 for each user terminal 3, and the arithmetic processing amount grasping unit 29 grasps the arithmetic processing amount in the arithmetic processing unit 28. (Step S5). Further, the control unit 27 detects whether or not there is a new communication request (connection request) from the user terminal 3 based on the demodulated signal from the demodulation unit 22 (step S6).

  As a result, when there is no communication request from the new user terminal 3, the fact is notified to the modulation class control unit 25. On the other hand, when there is a communication request from a new user terminal 3, it is next determined whether or not the calculation processing amount of the calculation processing unit 28 grasped in step S5 exceeds a predetermined value (step S7). ), And notifies the modulation class control unit 25 of the result.

  Based on the notification from the control unit 27, the modulation class control unit 25 does not require a new communication request from the user terminal 3 in step S6 or if there is a new communication request, in step S7, the arithmetic processing unit 28. In step S4, the modulation class for each user terminal 3 in communication determined by the modulation class determination unit 24 is supplied to the modulation unit 26. Thus, the modulation unit 26 modulates the transmission signal for each user terminal 3 from the control unit 27 based on the modulation class from the modulation class control unit 25 (step S8), and the modulated transmission signal is Along with the identification signal (designation signal) of the modulation class, the signal is transmitted from the plurality of antennas 20 to the corresponding user terminal 3 via the transmission / reception unit 21 (step S9). As a result, communication such as voice signals and packets is executed with the corresponding user terminal 3 using the modulation class designated by the base station 2.

  On the other hand, when the calculation processing amount of the calculation processing unit 28 exceeds a predetermined value in step S7, the modulation class control unit 25 determines the modulation class for each user terminal 3 determined by the modulation class determining unit 24. It is determined whether or not it is equal to or less than a set value (step S10). Here, the set value of the modulation class is set so that the frequency use efficiency is the best in the combination of the multiplexing number and the modulation class.

  As a result, when it is determined that the modulation class determined by the modulation class determination unit 24 exceeds the set value, the modulation class control unit 25 controls the modulation class to be equal to or less than the set value (step S11). The changed modulation class is supplied to the modulation unit 26. If the value is equal to or less than the set value, the modulation class determined by the modulation class determination unit 24 is supplied to the modulation unit 26 without being changed, and the process proceeds to step S8. .

  As described above, when a communication request from a new user terminal 3 is received in a state where the calculation processing amount of the calculation processing unit 28 exceeds a predetermined value, the user terminal 3 in communication is determined by the adaptive modulation method. If the modulation class is limited to be equal to or less than the set value, a new user terminal 3 can be spatially multiplexed. Therefore, it is possible to efficiently increase the number of multiplexing by the SDMA method by effectively using hardware. it can.

  In addition, since the upper limit of the modulation class is suppressed, demodulation is also easy. That is, for example, as shown in Table 1, the modulation class includes a modulation class based on a modulation scheme such as BPSK (Binary Phase Shift Keying), QPSK (Quadrature Phase Shift Keying), and QAM (Quadrature Amplitude Modulation). The transmission rate (throughput) varies depending on the modulation class, and the higher the degree of multi-leveling of one symbol (bit / symbol), that is, the higher the modulation class, the higher the speed. However, the higher the modulation class, the closer the inter-symbol distance becomes, so that signal separation becomes more difficult. Therefore, if the upper limit of the modulation class is suppressed, the intersymbol distance can be increased as compared with the case where a higher modulation class is used, and demodulation is also facilitated. FIG. 4 shows a QPSK constellation as an example.

(Second Embodiment)
In the second embodiment of the present invention, in the configuration of the base station 2 shown in FIG. 2, a communication request from a new user terminal 3 is made in a state where the calculation processing amount of the calculation processing unit 28 exceeds a predetermined value. When received, the modulation class of the user terminal 3 is limited so that the total value of the modulation classes determined by the adaptive modulation scheme for all user terminals 3 in communication is equal to or less than a predetermined value.

  FIG. 5 is a flowchart showing the operation of the base station 2 according to the present embodiment. 5, steps that perform the same processing as the processing shown in FIG.

  In the present embodiment, in step S7, when the calculation processing amount of the calculation processing unit 28 exceeds a predetermined value, the modulation class control unit 25 uses the modulation class determination unit 24 to determine the communication determined by the adaptive modulation method. It is determined whether or not the total value of the modulation classes in all the user terminals 3 is equal to or less than a predetermined value (step S20). Here, the total value of the modulation class is set so that the frequency use efficiency is the best in the combination of the multiplexing number and the modulation class, as in the first embodiment.

  As a result, when it is determined that the total value of the modulation class exceeds the predetermined value, the modulation class control unit 25 controls the modulation class of the user terminal 3 so that the total value is equal to or less than the predetermined value ( In step S21), the modulation class for each user terminal 3 whose total value is equal to or smaller than the predetermined value is supplied to the modulation unit 26. When the total value is equal to or smaller than the predetermined value, the modulation class determined in step S4 is changed. Without being supplied to the modulation unit 26, the process proceeds to step S8.

  Here, in step S21, for example, the modulation class of all user terminals 3 in communication is uniformly reduced, the modulation class is lowered in order from the higher modulation class, or the same as in the first embodiment. By setting a setting value to the modulation class of each user terminal 3, the total value of the modulation classes can be controlled to a predetermined value or less. In step S21, if the total value of the modulation class cannot be controlled below the predetermined value, a new connection request is rejected.

  As described above, when a communication request from a new user terminal 3 is received in a state where the calculation processing amount of the calculation processing unit 28 exceeds a predetermined value, the user terminal 3 in communication is determined by the adaptive modulation method. If the total value of the modulated modulation classes is limited to a predetermined value or less, a new user terminal 3 can be spatially multiplexed. Therefore, the number of multiplexing by the SDMA method can be efficiently increased by effectively using hardware. The same effects as those of the first embodiment can be obtained.

(Third embodiment)
In the third embodiment of the present invention, in the configuration of the base station 2 shown in FIG. 2, the arithmetic processing amount of the arithmetic processing unit 28 exceeds a predetermined value, and among the user terminals 3 in communication, the voice communication When a communication request from a new user terminal 3 is received in a state where the number of user terminals in (VoIP) exceeds a predetermined number, modulation determined by the adaptive modulation method for the user terminal 3 in communication Limit classes.

  FIG. 6 is a flowchart showing the operation of the base station 2 according to the present embodiment. In FIG. 6, steps that perform the same processing as the processing illustrated in FIG. 3 are denoted by the same reference numerals and description thereof is omitted.

  In the present embodiment, the control unit 27 grasps the amount of computation processing in the computation processing unit 28 (step S5), and grasps the number of user terminals in voice communication among the user terminals 3 in communication ( In step S25), the result is notified to the modulation class control unit 25. Thereafter, when there is a new communication request in step S6, the modulation class control unit 25 determines whether or not the calculation processing amount of the calculation processing unit 28 exceeds a predetermined value (step S7). If yes, it is further determined whether or not the number of user terminals during voice communication exceeds a predetermined number (step S26).

  As a result, when it is determined that the number of user terminals in voice communication exceeds a predetermined number, control is performed so as to limit the modulation class determined by the adaptive modulation scheme for the user terminal 3 in communication. (Step S27), the process proceeds to Step S8, and if the number of user terminals during voice communication does not exceed the predetermined number, the process proceeds to Step S8 as it is.

  Here, in step S27, for all user terminals 3 in communication, as in the first embodiment, control is performed so that the modulation class of each user terminal 3 is equal to or lower than the set value, or in the second embodiment. Similarly to the mode, the total value of the modulation classes of all user terminals 3 can be controlled to be equal to or less than a predetermined value, and among the user terminals 3 in communication, all the user terminals 3 in voice communication can be controlled. On the other hand, it is also possible to control the modulation class in the same manner as in the first embodiment and the second embodiment.

  Thus, in a state where the calculation processing amount of the calculation processing unit 28 exceeds a predetermined value and the number of user terminals in voice communication among the user terminals 3 in communication exceeds a predetermined number, a new user terminal When the communication request from the communication terminal 3 is received, if the modulation class of the user terminal 3 in communication is controlled, high throughput is not required in voice communication. It is possible to obtain the same effect as that of the first embodiment, such as effectively increasing the number of multiplexing by the SDMA method, by using. In particular, if the modulation class control target is limited to the user terminal 3 that is performing voice communication, it is possible to minimize the influence of a communication speed decrease due to the modulation class limitation.

  In addition, this invention is not limited only to the said embodiment, Many deformation | transformation or a change is possible. For example, in the third embodiment, the control unit 27 detects the type of a new communication request and notifies the modulation class control unit 25, and the modulation class control unit 25 performs step S6 shown in FIG. In step S7, it can be determined whether or not the type of the new communication request is voice communication, and in the case of the voice communication request, the process can be shifted to step S7. In this way, the number of multiplexed voice communications (accommodation number) can be further increased. Further, when the modulation class of each user terminal 3 is controlled to be equal to or lower than the set value as in the first embodiment, the set value is set according to the communication type, for example, in voice communication than in data communication. It can also be set to a lower modulation class. In the above embodiment, the calculation processing amount grasping unit 29 grasps the calculation amount in the arithmetic processing unit 28, and the modulation class control unit 25 adapts to the user terminal in communication based on the grasped calculation amount. The modulation class determined by the modulation method is controlled. In this case, the “calculation amount” in the calculation processing unit 28 includes “the number of calculations”.

It is a figure which shows an example of the mobile communication system which uses the base station which is a radio | wireless communication apparatus which concerns on 1st Embodiment of this invention. It is a functional block diagram which shows the structure of the principal part of the base station shown in FIG. It is a flowchart which shows operation | movement of the base station which concerns on 1st Embodiment. It is a figure which shows the constellation of QPSK. It is a flowchart which shows operation | movement of the base station 2 which concerns on 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the base station 2 which concerns on 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile communication system 2 Base station 3 User terminal 4 Network 20 Antenna 21 Transmission / reception part 22 Demodulation part 23 Communication quality acquisition part 24 Modulation class determination part 25 Modulation class control part 26 Modulation part 27 Control part 28 Arithmetic processing part 29 Computational processing amount Grasping part

Claims (6)

A communication control method for a wireless communication apparatus adopting a space division multiple access method and an adaptive modulation method,
An arithmetic processing amount grasping step for grasping an arithmetic processing amount of an arithmetic processing unit that processes transmission / reception data for the user terminal,
Modulation that limits the modulation class determined by the adaptive modulation scheme for the user terminal in communication when a communication request from a new user terminal is received in a state where the grasped arithmetic processing amount exceeds a predetermined value A class restriction step;
A communication control method for a wireless communication apparatus, comprising:   The wireless communication according to claim 1, wherein the modulation class limiting step further limits a modulation class for the user terminal in communication when the number of user terminals in voice communication exceeds a predetermined number. Device communication control method.   The communication control method for a wireless communication apparatus according to claim 2, wherein the communication request from the new user terminal is a voice communication request.   The communication of the radio communication apparatus according to any one of claims 1 to 3, wherein the modulation class limiting step limits a modulation class for each user terminal in communication so as to be equal to or less than a set value. Control method.   The modulation class limiting step limits the modulation class of a user terminal so that a total value of modulation classes for all user terminals in communication is equal to or less than a predetermined value. The communication control method of the radio | wireless communication apparatus as described in a term. A wireless communication device adopting a space division multiple access method and an adaptive modulation method,
An arithmetic processing unit for processing transmission / reception data for the user terminal;
An arithmetic processing amount grasping unit for grasping an arithmetic processing amount of the arithmetic processing unit;
A modulation class control unit that controls the modulation class determined by the adaptive modulation method for the user terminal in communication based on the calculation processing amount grasped by the computation processing amount grasping unit;
A wireless communication apparatus comprising:

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