Communication system, base station, mobile station, and radio co

Details Communication system, base station, mobile station, and radio co Communication system, base station, mobile station, and radio co

1996-06-13

1999-11-30

Ton, Dang

Multiplex communications

Communication techniques for information carried in plural...

Adaptive

370350, 370347, H04J 306

Patent

active

059955155

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

The present invention relates to a communication system, a base station, a mobile station and a radio communication system. In particular, the present invention relates to a communication system and a radio communication system for communication of digital data between a base station and a mobile station (a terminal station), and to a base station and a mobile station used for these systems.


BACKGROUND ART

Various systems for communication via a base station have been developed as a communication system for a radio communication. Specifically, in the case of a communication system which has already been put into practice as a radio telephone, for example, a telephone circuit for a radio communication is set between a base station connected through a wire telephone circuit to a telephone exchange side and a radio telephone apparatus (a mobile station) which is a terminal side telephone, thereby a call service being carried out between a called telephone connected through the telephone exchange and the radio telephone apparatus.
Such radio telephone apparatus as a terminal side apparatus includes a miniaturized portable radio telephone and a land mobile radio telephone mounted on an automobile, etc.
In a communication system employing such radio telephone apparatus, communication between the base station and the terminal side telephone apparatus has been carried out by a radio transmission of an analog signal. On the other hand, in order to efficiently use a transmission band, a communication system for carrying out communication between the base station and the terminal side by a radio transmission of a digital data is developed.
In this digital communication system, transmission and reception of the digital data between the base station and the mobile station are carried out in accordance with an efficient transmission system such as a TDM system (time division multiplex system), a TDMA system (time division multiple access system) and so on, and an audio signal is subjected to a high-efficiency coding and decoding. Therefore, as compared with an analog communication system, it is possible to use a transmission line very efficiently for thereby setting more transmission channels and so on and to realize transmission of a call sound having less noise.
Another communication system to which the digital communication system is applied includes a CDMA system (code division multiple access system), an FDMA system (frequency division multiple access system) and so on. In these systems, the transmission or the like is more efficient as compared with communication carried out by analog transmission.
An example of a TDMA system communication system which is proposed at present will be described. Frequency bands of 800 MHz and 1.5 GHz are used for communication, and in each of the frequency bands, a channel interval is set to 25 kHz. Transmission in a down circuit from the base station to the mobile station is carried out by the TDM system, and transmission in an up circuit from the mobile station to the base station is carried out by the TDMA system. A phase modulation such as a .pi./4 shift DQPSK modulation, for example, is employed as a transmission data modulation system.
In the transmission of the TDM system and the TDMA system, as shown in FIG. 1, for example, assuming that one frame is formed of six time slots of time slots 0 to 5 and a sub frame is formed of a half of one frame, transmission in the down circuit from the base station to the mobile station, for example, is carried out at timings of the time slots 1 and 4 of the sub frame period, and transmission in the up circuit from the mobile station to the base station is carried out during predetermined periods immediately before the time slots for transmission in the down circuit. In this case, the same frequency is used for transmission in each time slot.
A signal transmitted from the base station has a synchronizing word whose bit number is about 20 bits and which is located at a substantial center thereof. The synchronizing word is

REFERENCES:
patent: 3534264 (1970-10-01), Blasbalg et al.
patent: 4697281 (1987-09-01), O'Sullivan
patent: 4912705 (1990-03-01), Paneth et al.
patent: 4991184 (1991-02-01), Hashimoto
patent: 5327576 (1994-07-01), Uddenfeldt et al.
patent: 5590405 (1996-12-01), Daly et al.

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