JP2010183612A - Wireless communication system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform simultaneous transmission and reception communication to wireless terminals having a simultaneous transmission and reception function by selecting two sets of base stations. <P>SOLUTION: A system performs the simultaneous transmission and reception communication between a wireless terminal 300 having the simultaneous transmission and reception function and a base station 100 not having simultaneous transmission and reception function, by the TDMA-TDD (time division multiple access-time division duplex) method, and selects two sets of base stations 100, 200 not having the simultaneous transmission and reception function, thereby performing the simultaneous transmission and reception communication with respect to the wireless terminal 300. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication system and a wireless communication method for performing simultaneous transmission / reception communication between a base station and a wireless terminal having a simultaneous transmission / reception communication function.

    Generally, PHS (Personal Handy-phone System) wireless telephone communication is performed by a TDMA / TDD system (Time Division Multiple Access / Time Division Duplex system). In this PHS, for example, one frame is composed of 8 slots, 4 slots are allocated for uplink communication from the radio terminal to the base station, and 4 slots are allocated for downlink communication from the base station to the radio terminal. The timing is different from the 4-slot upstream communication period and the 4-slot downstream communication period.

    In such conventional PHS wireless communication, since the communication speed cannot be sufficiently high, a simultaneous transmission / reception method is proposed in which uplink and downlink communications are performed simultaneously with different carrier frequencies for the purpose of increasing the communication speed. The development thereof is underway (for example, Japanese Patent Application Laid-Open No. 2003-273770-Patent Document 1).

    In order to realize the PHS wireless communication of the simultaneous transmission / reception method, it is necessary to modify the internal functions of the wireless station in the base station and each wireless terminal from the existing ones. In particular, modification of the wireless station in the base station Can not be easily done due to high equipment costs. Therefore, if a system capable of simultaneous transmission / reception between a wireless terminal having a simultaneous transmission / reception function and a wireless base station is realized, the communication speed of PHS can be increased.

JP 2003-273770 A

  The present invention has been made in view of such a conventional technical problem, and an object of the present invention is to provide a wireless communication technology capable of simultaneous transmission / reception between a wireless terminal having a simultaneous transmission / reception function and a wireless base station. To do.

    The wireless communication system of the present invention includes a first base station, a second base station, and a wireless terminal that performs wireless communication simultaneously with the first base station and the second base station, and the first base station and the The second base station allocates time and / or frequency resources to the wireless terminal using inter-base station communication.

    In the wireless communication method of the present invention, a first base station to which a wireless terminal capable of simultaneous transmission / reception is connected requests a channel assignment to the wireless terminal to a second base station to cooperate with the own station. Transmitting, to the first base station, the second base station, in response to the request, transmitting information about whether or not to allocate a channel to the wireless terminal, and the first base station. Transmitting, to the wireless terminal, information indicating that simultaneous communication with the first base station and the second base station is possible according to the information on whether the allocation is possible; and And performing wireless communication simultaneously with one base station and the second base station.

  According to the wireless communication technology of the present invention, a wireless terminal having a simultaneous transmission / reception function can perform simultaneous transmission / reception with two wireless base stations, and as a result, an advantage that communication speed can be increased. There is.

The block diagram which shows the hardware constitutions of the radio | wireless communications system of the 1st Embodiment of this invention. The block diagram which shows the structure of the base station used as the master station and slave station in the said embodiment. The block diagram of the radio | wireless terminal in the said embodiment. The block diagram which shows the detailed internal structure of the radio | wireless part in the said radio | wireless terminal. Explanatory drawing of communication operation | movement with the conventional PHS communication system and the PHS simultaneous transmission / reception communication system of the 1st Embodiment of this invention. Explanatory drawing of operation | movement of the pseudo simultaneous transmission / reception by the radio | wireless communications system of the said embodiment. The sequence diagram of the simultaneous transmission / reception operation | movement by the said embodiment. 7 is a flowchart of a slave station determination routine in the simultaneous transmission / reception operation. FIG. 3 is a block diagram of a hardware configuration of a system that performs synchronous inversion communication through an I ′ line in the embodiment. The block diagram of the hardware constitutions of the system which performs synchronous inversion communication through a radio | wireless communication line in the said embodiment. The block diagram which shows the hardware constitutions of the radio | wireless communications system of the 2nd Embodiment of this invention. The block diagram which shows the structure of the base station used as the master station and slave station in the said embodiment. The sequence diagram of the simultaneous transmission / reception operation | movement by the said embodiment.

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

(First embodiment)
As shown in FIG. 1, the radio communication system according to the first embodiment of the present invention is a simultaneous transmission / reception method between a parent base station 100 and a child base station 200 and a terminal 300 that are predetermined to be paired It is a system that performs communication. The terminal 300 will be described with reference numerals such as 300A, 300B,... When it is necessary to distinguish it from other terminals.

  The parent base station 100 and the child base station 200 in the present embodiment have the configuration shown in FIG. These master stations and slave stations normally operate individually as radio base stations for PHS radio communication, and are connected to each other by an I 'circuit network. In addition, as shown in FIG. 1, base stations located in close proximity to each other are connected by an inter-station connection cable 400 to perform various communications. In the present embodiment, it is assumed that master station 100 and slave station 200 transmit an inversion instruction signal through inter-station connection cable 400.

  As shown in FIG. 2, the parent base station 100 includes two antennas 101A and 101B for diversity reception, an RF unit 102 for transmitting and receiving high-frequency radio signals, a demodulator 103 for baseband, and modulation from the baseband. Unit 104, TDMA / TDD processing unit 105, connection control unit 106 for controlling each element by executing a program installed by the CPU, interface 107 with I 'line, inter-base station monitoring for monitoring the quality of radio communication signals And an inversion instructing unit 109 that outputs a command to invert the uplink period / downlink period.

  On the other hand, the base station 200 serving as a slave station includes two antennas 201A and 201B for diversity reception, an RF unit 202 for transmitting and receiving high-frequency radio signals, a demodulation unit 203 for baseband, and a modulation unit 204 for baseband. , A TDMA / TDD processing unit 205, a connection control unit 206 that executes a program installed by the CPU to control each element, an interface 207 with an I ′ line, and an inter-base station monitoring unit 208 that monitors the quality of a wireless communication signal Then, an inversion control unit 209 that receives the timing inversion command of the uplink / downward transmission / reception period from the inversion instruction unit 109 of the master station 100 and inverts the uplink period / downlink period of the TDMA / TDD processing unit 205 is provided.

  The terminal 300 having the simultaneous transmission / reception function has the functional configuration shown in FIG. 3. The terminal 301 superimposes a digital signal of voice and data on the baseband signal to the antenna 301, and further converts it into a high-frequency signal for transmission. Modulated and output, demodulated to baseband from high frequency received signal received by antenna 301, further controls radio unit 302 for extracting voice and data digital signal, controls overall function of this unit, and voice A control unit 303 that performs A / D conversion of the analog signal and vice versa, an amplification unit 304 that amplifies the received and demodulated analog audio signal, and an audio signal from the amplification unit 304 as an audible sound The output speaker 305, a microphone 306 that receives sound waves and converts them into electrical signals, amplifies the signal from the microphone 306, and Amplifying section 307 given as grayed audio signal, the display unit 308 to display the decoded information and generated information in the control unit 303 then includes an operation unit 309 for performing numeric keypad other button operation input.

  The radio unit 302 that enables simultaneous transmission / reception of the terminal 300 is configured as shown in FIG. 4, and a circulator 311 for inputting a reception signal of the antenna 301 and simultaneously outputting a transmission signal to the antenna 301, A high-frequency amplifier 312 on the transmission side for supplying a high-frequency transmission signal to the circulator 311, a transmission RF mixer 313 for converting a baseband transmission signal into a high-frequency transmission signal for transmission, and a modulated transmission signal is amplified by the transmission RF mixer 313. An amplifier 314 for outputting and a modulator 315 for modulating the transmission signal into a baseband signal are provided. The radio unit 302 further includes a frequency switcher 316 that switches the transmission frequency and supplies it to the transmission RF mixer 313, and local oscillators 317A and 317B that oscillate at different predetermined frequencies.

  Further, the radio unit 302 serves as a reception system for demodulating the reception signal of the antenna 301, a high frequency amplification unit 321 for amplifying the high frequency reception signal output from the circulator 311, and the high frequency reception signal amplified by the high frequency amplification unit 321 to a predetermined base. A reception RF mixer 322 for converting to a band signal, a band pass filter (BPF) 323 for removing a frequency signal outside the main signal band from the baseband signal converted by the reception RF mixer 322, and a baseband output by the BPF 323 A demodulator 324 for demodulating the received signal, a frequency switch 325 for switching the reception frequency to the reception RF mixer 322, and local oscillators 326A and 326B for oscillating at different predetermined frequencies. Yes.

  Next, the simultaneous transmission / reception operation by the wireless communication system having the above configuration will be described. In the TDMA / TDD PHS, when a radio base station does not have a simultaneous transmission / reception function, between the base station and the radio terminal, as shown in FIG. A total of 8 slots are defined as one frame, different frequencies are allocated to each of the 4 slots, and the uplink and downlink frequencies are common, the first slot is the control channel (C-CH), and the base stations are assigned to the second to fourth slots, respectively. -Assign different frequencies as wireless communication channels between terminals. Now, assuming that a connection is established between the base station and a certain terminal at the frequency F2 of the second slot, downlink communication is performed at the frequency F2 in the second slot in the downlink period, and then the second slot in the uplink period. Uplink communication is performed on the slot at the frequency F2. That is, in normal PHS wireless communication, data for one time slot can be transmitted and received in one frame.

  On the other hand, in the wireless communication system according to the present embodiment, as shown in FIG. 5 (b), two existing base stations are used, and twice as much data is transmitted with a wireless terminal having a simultaneous transmission / reception function. Amount can be sent and received. That is, the base station 100 that is the base station of the wireless terminal 300 communicates using the frequencies F1 to F4, while the base station 200 that is the slave station communicates using the frequencies F5 to F8. In response to the simultaneous transmission / reception request from, the synchronization of transmission / reception on the side of the slave station 200 is inverted from the normal 4-slot down period—the 4-slot upstream period to become the 4-slot upstream period—the 4-slot down period.

  Then, as shown in FIG. 6, at the timing of the first second slot, downlink communication is performed between the master station 100 and the terminal 300 at the frequency F2, and at the same time, between the slave station 200 and the terminal 300. Uplink communication is performed at frequency F6, and terminal 300 having a simultaneous transmission / reception function simultaneously performs reception at frequency F2 and transmission at frequency F6. Then, at the timing of the sixth slot in one frame, the upstream communication is performed at the frequency F2 between the master station 100 and the terminal 300, and at the same time, the slave station 200 and the terminal 300 at the frequency F6. Downlink communication is performed, and the terminal 300 transmits at the frequency F2 and receives at the frequency F6 at the same time. As a result, as shown in FIG. 1, the terminal 300A having the simultaneous transmission / reception function is connected to the existing base stations 100 and 200 having no simultaneous transmission / reception function by using the frequencies F2 and F6 allocated thereto. And another similar terminal 300B also has a frequency F3 assigned to the existing base stations 100 and 200 having no simultaneous transmission / reception function. F7 enables communication at twice the conventional communication speed.

  The pseudo simultaneous transmission and reception according to the present embodiment will be described with reference to the sequence diagram of FIG. A simultaneous transmission / reception connection request is transmitted from terminal 300 to a base station having an optimal communication state (step SQ1). After receiving this request, the base station operates as the master station 100 thereafter. The base station 100 that has become the parent station selects another base station having the highest reception level as the slave station 200 by the inter-base station monitoring unit 108 (step SQ3) and In this case, a channel allocation and transmission / reception period timing inversion command is transmitted through the inter-station connection cable 400 (step SQ5).

  The base station that has received the synchronization inversion instruction at its inversion control unit 208 determines whether or not the allocated channel can be used in the own station (step SQ7), and if it is free, the TDMA / TDD processing unit 205 determines whether the uplink / downlink is available. The period is reversed (step SQ9), and a channel allocation OK signal is returned to the master station 100 as a signal that acknowledges becoming a slave station (step SQ11). When receiving the channel assignment OK signal, master station 100 transmits a simultaneous transmission / reception communication request acceptance notification to terminal 300 (step SQ13).

  Note that the selection of slave stations in steps SQ3 to SQ13 is performed according to the procedure shown in detail in the flowchart of FIG. That is, according to the signal level of the radio signal from the other station monitored by the inter-base station monitoring unit 108 (step S1), priorities are assigned to the slave station candidates in descending order of the signal level (step S3). Inquiries about free channels are made in order from the base station (step S5), and the base station having available free channels is determined as a slave station (step S7).

  If the terminal 300 receives the simultaneous transmission / reception acceptance notification, the terminal 300 subsequently activates the original simultaneous transmission / reception function and, as described above, for example, using the frequencies F2 and F6 in the second slot and the sixth slot, Substantial simultaneous transmission / reception is executed by reversing the transmission / reception timings with the slave station 200 and causing them to communicate simultaneously (steps SQ15 to SQ25).

  Thus, according to the wireless communication system of the present embodiment and the wireless communication method executed by the wireless communication system, the terminal 300 having the simultaneous transmission / reception function also applies to the existing base stations 100 and 200 having no simultaneous transmission / reception function. It is possible to communicate at almost twice the communication speed of a base station that does not have the simultaneous transmission / reception function.

  In the wireless communication system of the above-described embodiment, the timing inversion command / synchronization inversion acceptance signal between the base stations 100 and 200 is transmitted and received through the existing inter-station connection cable 400. However, the present invention is not limited to this. However, as shown in the system diagram of FIG. 9, in the case of PHS, since all base stations are connected by the I ′ line 410 and the network 420, the corresponding base station 100 is connected through this I ′ line. , 200 transmission / reception period timing inversion command / synchronization inversion acceptance signal can be exchanged. Alternatively, as shown in FIG. 10, a timing inversion command / synchronization inversion in a transmission / reception period is received and transmitted / received over a wireless communication line 430 using an empty slot or a control slot between the master station 100 and the slave station 200. It can also be.

  In the synchronous inversion control, not the slave station 200 but the master station 100 may accept the simultaneous transmission / reception request and perform control to reverse the uplink period / downlink period of the own station when the slave station is determined. . In addition, for each base station, a plurality of stations of other base stations are assigned with priorities as slave station candidates, and in response to simultaneous transmission / reception requests from wireless terminals, Thus, an empty channel is inquired in order from the highest priority, and another base station with the highest priority is selected as a slave station among the slave station candidates having the empty channel.

  Further, in the process of selecting the base station that becomes the slave station 200 by the base station that becomes the master station 100, a parent station-slave station pair can be registered in each connection control unit 106 in advance. Then, when there is no empty channel in a base station that should be a predetermined slave station, the transition to simultaneous transmission / reception may be suspended and a simultaneous transmission / reception request may be continuously transmitted from the terminal 300. The system configuration in this case is simpler than in the case of the above embodiment.

(Second Embodiment)
FIG. 11 shows a wireless communication system according to the second embodiment of the present invention. In the wireless communication system according to the present embodiment, the base station 100 does not have an existing simultaneous transmission / reception function. In the case where the stations 110 and 120 are provided, pseudo-simultaneous simultaneous transmission / reception is performed between the base station 100 and the wireless terminal 300 having the simultaneous transmission / reception function.

  The configurations of the first radio station 110 and the second radio station 120 in the base station 100 are as shown in FIG. 12, and the configurations of the master station 100 and the slave station 200 in the first embodiment shown in FIG. It is common. However, the present embodiment is different in that the first radio station 110 and the second radio station 120 in the base station 100 are connected by an intra-station connection line 450. The wireless terminal 300 having the simultaneous transmission / reception function in the present embodiment is the same as that in the first embodiment, and has the configuration shown in FIGS.

  The simultaneous transmission / reception operation according to the present embodiment is as shown in the sequence diagram of FIG. In the case of the present embodiment, the first wireless station 110 makes a simultaneous transmission / reception request from the terminal 300 without the slave station determination process of step SQ3 being added to the sequence diagram of the first embodiment shown in FIG. If received, a channel assignment / synchronization inversion instruction is immediately given to the second radio station 120 through the intra-station connection line 450 (steps SQ1, SQ5). The procedures after step SQ7 are the same as those in the first embodiment. The first radio station 110 and the second radio station 120 in the same base station 100 are not determined in advance, and the radio station that has received the simultaneous transmission / reception switching request from the terminal 300 is the first radio station 110. The only difference is that the remaining radio stations in the same base station 100 become the second radio station 120. Further, between the first radio station 110 serving as a master station and the second radio station 120 serving as a slave station, the first radio station 110 may be configured to invert the uplink period / downlink period.

  According to the present embodiment, a master station and a slave station are determined between two radio stations in the same base station, one of the uplink periods / downlink periods is inverted, and pseudo-simultaneous simultaneous transmission / reception with terminal 300 Therefore, the procedure for determining the base station to be a slave station based on the received signal level is not required as in the first embodiment, and the system can be simplified accordingly.

  Even in the present embodiment, if each base station cannot find a free channel in its own radio station, it communicates with other base stations that are located in geographically different locations. It is also possible to provide a function of selecting a radio station having a high reception level and a free channel as a slave station in the same procedure as in the above embodiment.

  DESCRIPTION OF SYMBOLS 100 ... Master station, 200 ... Slave station, 300 ... Terminal, 400 ... Inter-station connection cable, 101A, 101B ... Antenna, 102 ... RF unit, 103 ... Demodulation unit, 104 ... Modulation unit, 105 ... TDMA / TDD processing unit, DESCRIPTION OF SYMBOLS 106 ... Connection control part 107 ... I / F part 108 ... Inter-base station monitoring part 109 ... Inversion instruction part 110 ... 1st radio station 120 ... 2nd radio station 201A, 201B ... Antenna, 202 ... RF 203: Demodulation unit 204 ... Modulation unit 205 ... TDMA / TDD processing unit 206 ... Connection control unit 207 ... I / F unit 208 ... Inter-base station monitoring unit 209 ... Inversion control unit 301 ... Antenna 311 ... circulator, 312 ... amplifying unit, 313 ... transmitting RF mixer, 314 ... amplifying unit, 315 ... modulating unit, 316 ... frequency switching unit, 317A, 317B ... local oscillator, 32 ... amplifier, 322 ... reception RF mixer, 323 ... bandpass filter (BPF), 324 ... demodulation unit, 325 ... reception RF mixer, 326A, 326B ... local oscillator.

Claims (2)

A first base station, a second base station, and a wireless terminal that performs wireless communication simultaneously with the first base station and the second base station,
A wireless communication system, wherein the first base station and the second base station allocate time and / or frequency resources to the wireless terminal using inter-base station communication. A first base station to which a wireless terminal capable of simultaneous transmission and reception is connected transmits a request for channel assignment to the wireless terminal to a second base station;
The second base station, in response to the request, transmitting information on whether or not to allocate a channel to the wireless terminal to the first base station;
The first base station transmitting information indicating that simultaneous communication with the first base station and the second base station is possible to the wireless terminal in accordance with the allocation permission information;
And a step of performing wireless communication simultaneously with the first base station and the second base station.

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