Mobile communications system

Communications: electrical – Continuously variable indicating – With meter reading

Patent

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Details

34082552, 371 471, 455 311, 455 321, 455 68, 455 70, 455 95, H04B 700, H04Q 100, H04Q 700

Patent

active

058050760

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

This invention is utilized in mobile radio communications, and is suitable for use in cellular telecommunication systems and radio paging systems. It relates in particular to the control techniques involved in changing transmission parameters or transmission mode.


BACKGROUND TECHNOLOGY

Recent years have witnessed a growing demand for mobile communications and a desire for a diversification of services. In response to these pressures, there are now communications systems with variable transmission parameters or transmission nodes, and these serve as a means for making effective use of limited frequency resources and for responding flexibly to traffic fluctuations and service diversification. The term "transmission parameters" includes for example, transmission speed, modulation scheme, error control scheme (forward error correction, number of retransmissions, and application or non-application of interleaving), frequency, and transmitted information (type of service). Combinations of these transmission parameters are termed "transmission modes". Hereinafter, transmission parameters or a transmission mode will be called the "transmission form".
Prior art examples of selective radio paging systems will be explained with reference to FIG. 15-FIG. 19. FIG. 15 is an overall block diagram of a selective radio paging system. FIG. 16 shows an asynchronous format paging signal sequence. FIG. 17 is a flowchart showing the operation of a selective radio paging system employing asynchronous format paging signal sequences. FIG. 18 shows a synchronous format paging signal sequence. FIG. 19 is a flowchart showing the operation of a selective radio paging system employing synchronous format paging signal sequences. Central station 1, shown in FIG. 15, functions both as a control station which controls base stations 10-17, and as a base station. Central station 1 transfers to base stations 10-17, via links 30-37, paging signal sequences comprising paging signal groups R that are to be transmitted to radio paging receivers 20-22, plus synchronization signals S and control signals C. Central station 1 and base stations 10-17 transmit paging signal sequences while maintaining mutual phase synchronization.
The case where paging signal sequences have an asynchronous format will be explained with reference to FIG. 16 and FIG. 17. As shown in FIG. 16(1), paging signal sequences transmitted from central station 1 and base station 10-17 comprise: synchronization signals S for identifying the headers of frames of the paging signal sequence; control signals C for specifying the transmission form and switching the transmission form of radio paging receivers 20-22; and paging signal groups R. As shown in FIG. 16(2), a paging signal group R contains address signals A1-Ak which are customer ID signals, and message signals M1-Mk. The value of k changes according to traffic conditions. An error detection code is usually added to control signal C, and this increases the transmission reliability. In FIG. 16, the transmission form is initially ".alpha." and the paging signal groups are transmitted in this form, but the transmission form is altered by the control signal C which is received immediately before time t0, and subsequent to time to the transmission form is ".beta." and paging signal groups are transmitted in this form.
As shown in FIG. 17, when a synchronization signal S is detected in a received paging signal sequence (S1) and no error is detected in the following control signal C (S2), preparations are made to receive the subsequent paging signal group R on the basis of the transmission form indicated by this received control signal C (S3). Paging signal group R is then received (S4). It is checked whether or not the address number of a given radio paging receiver 20-23 (hereinafter, termed "pagers" for short) is present in the received paging signal group R (S5). If it is, paging processing is carried out, wherein, an alert is emitted by the pager in question, and message signals M1-Mk that follow address signa

REFERENCES:
patent: 4392242 (1983-07-01), Kai
patent: 4720710 (1988-01-01), Akahori et al.
patent: 4777655 (1988-10-01), Numata et al.
patent: 4783654 (1988-11-01), Ichikawa
patent: 5574972 (1996-11-01), Hulbert
patent: 5574977 (1996-11-01), Joseph et al.

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