JP4002562B2 - Private branch exchange system and synchronization method thereof - Google Patents

Description

  The present invention relates to a private branch exchange system for connecting wireless terminals and a synchronization method thereof, and more particularly, to a private branch exchange system and a synchronization method thereof in which confirmation of wireless communication synchronization is simplified.

  In a private branch exchange system for connecting a conventional wireless terminal and a wireless communication synchronization method in the system, a wireless communication system in a narrow range, for example, a PHS (Personal Handyphone System) is used. The super frame applied to the personal digital cellular mobile phone network standardized by “RCR / STD-28” in U.S. Pat.

  The super frame is employed in order to reduce power consumption on the portable wireless terminal side. For example, while a frame used in PHS has a period of 5 ms, a super frame is formed so as to follow a call signal with a longer period. The superframe synchronization signal forming the superframe is provided in the private branch exchange system with a 125 μs period PCM (pulse code modulation) synchronization signal based on a frequency of 8 kHz corresponding to the digitized voice in the private branch exchange system as a reference. For example, a superframe period such as 750 ms, 1040 ms, or 1200 ms is used for the PHS period.

  FIG. 1 is a diagram illustrating an example of a block configuration when a conventional private branch exchange system includes a wireless terminal.

  The private branch exchange 100 has a main control unit 101 and a plurality of wireless terminal interfaces 102, to which a PCM-HW (PCM highway) 103 and an SF (superframe) synchronization signal line 104 are connected. The main control unit 101 includes a PCM-HW signal generation unit 111 and an SF cycle generation unit 112. The wireless terminal interface 102 includes a CODEC (encoding / decoding combined device) 113, an SF synchronization signal receiving unit 114, and an antenna 115, and wirelessly communicates with the wireless terminal 105 based on the moving PHS, for example, according to the above standard. One wireless terminal 105 can access a nearby wireless terminal interface 102 while moving.

  In the private branch exchange 100, the PCM-HW 103 is normally connected from the main control unit 101 to the terminal, and communicates in synchronization with the PCM synchronization signal. As described above, the super frame is necessary for the wireless terminal 105 only for wireless communication. Accordingly, the super frame is used only by the wireless terminal 105 and the wireless terminal interface 102. However, there are a plurality of wireless terminals 105 and wireless terminal interfaces 102, and miniaturization is required. Further, a plurality of synchronization signals are required at the same time. Therefore, the SF synchronization signal is generated by the SF cycle generation unit 112 of the main control unit 101 and distributed to the wireless terminal interface 102, and the wireless terminal 105 is synchronized.

  In such a configuration, the wiring of the SF synchronization signal line 104 is necessary in parallel with the PCM-HW 103 from the main control unit 101 to the mounting area and the planned mounting area of the wireless terminal interface 102. Therefore, the SF synchronization signal line 104 is redundant for the private branch exchange 100 that does not use the wireless terminal 105. On the other hand, in the existing private branch exchange 100 that is wired up to the planned installation area, additional wiring is difficult even if the wireless terminal interface 102 is to be added in addition to the planned installation.

  The problem to be solved is that when a wireless terminal interface connected to a wireless terminal such as a PHS is installed in a private branch exchange, a transmission line of a super frame (SF) synchronization signal distributed from the main control unit to each wireless terminal interface is SF. Since the synchronization signal line is wired in parallel with the PCM highway (PCM-HW) for the exchange function, it is not only inflexible with respect to the change in the number of installed wireless terminal interfaces, but also redundant and uneconomical. It is inevitable to be.

  The main feature of the present invention is that the SF synchronization signal is transmitted using the PCM highway for downlink data from the main control unit to each wireless terminal interface in order to delete the SF synchronization signal line.

  That is, the SF synchronization signal is placed at a predetermined bit position on the PCM highway for downlink data.

  The private branch exchange system and the synchronization method thereof according to the present invention have the advantage that the SF synchronization signal line can be deleted because the SF synchronization signal is transmitted using the PCM highway, so that the economy of wiring can be obtained. Furthermore, since the SF synchronization signal reaches not only the wireless terminal but also the terminal interface, there is an advantage that flexibility can be given to an increase in equipment of the wireless terminal interface.

  The purpose of deleting the SF synchronization signal line is realized by superimposing and transmitting the SF synchronization signal at a predetermined bit position using a PCM highway (abbreviated as PCM-HW).

  A basic form of the present invention will be described as Example 1 with reference to FIG. FIG. 2 is a diagram showing an example of a block configuration of the private branch exchange 10 corresponding to FIG.

  The private branch exchange 10 has a main control unit 1 and a plurality of wireless terminal interfaces 2, and a PCM-HW (PCM highway) 3 is connected therebetween. The main control unit 1 includes a PCM-HW signal generation unit 11, an SF (superframe) cycle generation unit 12, and an SF synchronization signal superposition unit 13. The wireless terminal interface 2 includes an SF synchronization signal separation unit 14, a CODEC (codec / encoding / decoding device) 15, an SF synchronization signal reception unit 16, and an antenna 17, for example, a wireless terminal using a moving PHS (personal handyphone system). 5 and the above-mentioned RCR / RTD-28 standard. One wireless terminal 5 can access a nearby wireless terminal interface 2 while moving.

  In the private branch exchange 100, the PCM-HW 3 is normally connected from the main control unit 1 to the terminal and communicates in synchronization with the PCM synchronization signal. As described above, the super frame (sometimes abbreviated as SF) is necessary for the wireless terminal 5 only for wireless communication, but the PCM generated by the PCM-HW signal generation unit 11 of the main control unit 1 is used. It is formed by superimposing the SF synchronization signal generated by the SF cycle generator 12 on the -HW signal. The superimposition position is a predetermined bit position in the SF synchronization signal superimposition unit 13, and the transmission destination is the wireless terminal interface 2 via the PCM-HW3.

  In the wireless terminal interface 2, the SF synchronization signal separator 14 connects the PCM-HW3. The communication received via the PCM-HW 3 and the control signal are passed to the CODEC 15 as in the prior art. On the other hand, the SF synchronization signal is separated from the PCM-HW signal when received by the SF synchronization signal separation unit 14 via the PCM-HW 3 and received by the SF synchronization signal reception unit 16.

  The difference from the prior art is that the SF sync signal superimposing unit 13 in the main control unit 1 and the SF sync signal separating unit 14 in the wireless terminal interface 2 are added, while the conventional SF sync signal line is deleted.

  As a method of superimposing the SF synchronization signal on the PCM-HW, an SF bit corresponding to a specific bit of downlink data sent from the main control unit 1 to all the wireless terminal interfaces 2 is set. The SF synchronization signal can be sent to each terminal interface by setting the superframe period using the SF bit, the PCM synchronization signal, and the reference clock. Therefore, the SF synchronization signal can be separated from the PCM-HW based on the set rule in the wireless terminal interface.

  Superframe setting according to the present invention will be described as a second embodiment with reference to FIG. 3 and FIG. That is, the SF synchronization signal is notified by using 8 bits of the data bus sent from the main control unit 1 to the HW 3 for generating the SF cycle.

  FIG. 3 shows that the main control unit 1 receives 8 bits in total of 7 bits in parallel from the data bus and 1 bit of the SF periodic signal, and sends them to the downstream data bus of the PCM-HW 3 via the data selector. This is a bit generation circuit. This circuit includes an SF value setting register (SF_VALUE) 20, six SF registers (_A to _F) 21 to 26, a logic circuit 30 for sending an internal SF synchronization signal (SFin) as an external SF synchronization signal (SFout), and Corresponding to the SF registers 21 to 26, logic circuits 31 to 36 for sending corresponding bits to each of six highway (HW) data selectors are shown.

  The SF value setting register 20 is a write-only 16-bit register, and various SF cycles can be set by setting values in this register in hexadecimal notation. For example, when generating a super frame of 3.12 seconds, the initial value can be set to “H′207F” and the count value can be set to “H′6180”. This output is supplied to all of the logic circuits 30-36.

  Each of the SF registers 21 to 26 is a write-only 16-bit register, and by setting a value in this register, SF data for setting the MSB bit in the time slot TS127 from HW-A to HW-F can be selected. . This register is initialized to “H′0000” by reset.

  FIG. 4 is an explanatory diagram showing a function that allows selection of data to be set in the SF bit of each HW by setting bits 1 and 0. When bits 1 and 0 are “0, 0”, the SF synchronization signal inside the main control unit is sampled and transmitted to the HW as the SF bit. In the case of bits “0, 1”, the nSFin signal input from the outside is sampled and transmitted to the HW as the SF bit. When bit 1 is “1”, transmission of the SF bit is stopped regardless of the value of bit 0 being “0, 1”.

  The SFout register is a write-only 16-bit register, and the SF signal of nSFout output can be selected by setting a value in this register. This register is initialized to “H′0000” by reset.

  FIG. 5 is an explanatory diagram showing a function of selecting an SF signal of nSFout output by setting bits 1 and 0. When bits 1 and 0 are bits “0, 0”, the SF synchronization signal inside the main control unit is output to the nSFout terminal. In the case of bits “0, 1”, an externally input nSFin signal is output to the nSFout terminal. When bit 1 is “1”, signal transmission to the nSFout terminal is stopped regardless of the value of bit 0 being “0, 1”, and “1” is always transmitted.

  The superframe setting according to the present invention will be described as a third embodiment with reference to FIG. 6 and FIG.

  As shown in FIG. 6, a conventional 5MS frame, which is a PHS cycle, is generated by generating 250 μs pulses in a 20 ms 5 ms cycle from a 250 μs cycle signal. The 250 μs periodic signal is a periodic signal of the 4 kHz clock CK4k generated from the 8 MHz clock of the private branch exchange. Next, M times 5MS frames are generated in the superframe period. For example, there is a case in which a 5 ms pulse is generated with a frame period of 100 ms of “M = 20”, and this is made one block. Further, for example, the above-described superframe having a 1040 ms cycle can be generated by counting 128 times 5 ms.

  In the private branch exchange system, the superframe necessary for the wireless terminal can be easily transmitted from the main control unit to the wireless terminal interface by using a method of superimposing a signal on a predetermined bit position on a highway common to various terminals. The present invention can also be applied to applications where it is indispensable to transmit a new signal generated in the network without providing a new signal line.

It is explanatory drawing which showed an example of the block configuration in the conventional private branch exchange system. It is explanatory drawing which showed one Embodiment of the block structure in the private branch exchange system by this invention. Example 1 FIG. 3 is an explanatory diagram showing an embodiment of superframe synchronization signal superposition in the private branch exchange system in FIG. 2. (Example 2) It is explanatory drawing which showed one Embodiment of the bit application in SF_register of FIG. (Example 2) FIG. 4 is an explanatory diagram showing an embodiment of bit application in the SFout register of FIG. 3. (Example 2) It is the time chart which showed one Embodiment of the super-frame synchronizing signal generation process in the private branch exchange system in FIG. (Example 3)

Explanation of symbols

1 Main control unit 2 Wireless terminal interface 3 PCM-HW
5 Wireless terminal 11 PCM-HW signal generation unit 12 SF period generation unit 13 SF synchronization signal superposition unit 14 SF synchronization signal separation unit 15 CODEC
16 SF synchronization signal receiver 20 SF_VALUE (SF value setting register)
21 SF_A (SF register A)
22 SF_B (SF register B)
23 SF_C (SF register C)
26 SF_F (SF register F)
30-36 logic circuit

Claims (6)

In a private branch exchange system that connects wireless terminals using superframes,
A main control unit that mainly controls the functions of the private branch exchange system is connected to a wireless terminal that moves on the one hand using radio waves, and on the other hand, a communication path is formed between the main control unit and the main control unit. A plurality of wireless terminal interfaces for interconnecting and communicating the wireless terminals,
The main control unit superimposes a superframe synchronization signal for synchronizing the wireless terminal on a predetermined bit position of a downlink for sending data to each of the wireless terminal interfaces, and the wireless terminal interface receives data received from the main control unit A private branch exchange system characterized in that a superframe synchronization signal is separated and extracted from a predetermined bit position of the downlink of the network.   2. The private branch exchange system according to claim 1, wherein the main control unit includes a highway signal generation unit that generates a PCM (pulse code modulation) highway signal, a superframe synchronization signal generation unit that generates a superframe synchronization signal, and While receiving a bit signal to be generated by the highway signal generation unit and output to the highway, the superframe synchronization signal generated by the superframe synchronization signal generation unit is superimposed on a predetermined position of the bit signal and transmitted to the highway A private branch exchange system comprising a superframe synchronization signal superimposing unit.   2. The private branch exchange system according to claim 1, wherein the wireless terminal interface captures a PCM highway signal received from the main control unit via a PCM (pulse code modulation) highway, while a predetermined bit of the PCM highway signal. A superframe synchronization signal separation unit that separates the superframe synchronization signal from a position; a CODEC (encoding / decoding device) that receives a PCM highway signal from the superframe synchronization signal separation unit and imports it into a non-decoded unit; A private branch exchange system comprising: a superframe synchronization signal receiving unit that receives the superframe synchronization signal from a superframe synchronization signal separation unit and forms a superframe.   4. The private branch exchange system according to claim 1, wherein the highway into which the superframe synchronization signal is inserted is a downlink data bus from the main control unit to the wireless terminal interface, and the main control unit One signal value setting register for setting one superframe period, six superframe registers for specifying a bit signal set by the signal value setting register at a predetermined position on the downlink data bus, and one superframe signal A private branch exchange system comprising: a superframe output register for setting one selection value; and six data selectors for selecting each of six data bits according to the output of the superframe register and sending the selected data bits to a highway data selector .   In a private branch exchange system synchronization method for connecting wireless terminals using superframes, a superframe synchronization signal is superimposed on a predetermined bit position of a downlink for transmitting data from the main control unit of the private branch exchange system to each of a plurality of wireless terminal interfaces. A method of synchronizing a private branch exchange system, characterized in that 6. The method of synchronizing a private branch exchange system according to claim 5, wherein a superframe synchronization signal is separated and extracted from the predetermined bit position set in advance by the wireless terminal interface. .

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