Mobile communications system and communication channel control method for the same

• US 5,528,668 A
• Filed: 05/09/1994
• Issued: 06/18/1996
• Est. Priority Date: 05/10/1993
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Aihara, Makoto
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): OEHLING, GEORGE J
• Application Number:
  US08/239,965
• Time in Patent Office: 771 Days
• Field of Search: 379/58, 379/59, 379/60, 455/33.1, 455/33.2, 370/95.1, 370/95.3, 370/60, 370/60.1, 370/16, 370/58.1
• US Class Current: 455/422.1
• CPC Class Codes: H04W 88/181 Transcoding devices; Rate adaptation devices

Abstract

In the construction of a mobile communications system wherein coder-decoder units for high-efficiency coding which should originally be placed in base stations are arranged in a concentrated manner in a mobile exchange office, a circuit changing-over switch is provided as a part of the communications circuits extending from the base stations to the mobile exchange office and the coder-decoder units in the same office. Consequently, the total number of coder-decoder units is reduced to a number which is smaller than the total number of base stations and which corresponds to the volume of traffic of the entire system. Further, when a communication channel is prepared at the time of a call origination or hand-over, since the setting of a communication channel is completed after synchronization is established between a base station and a coder-decoder unit, interruptions of the service are prevented at an initial stage of setting of a communication channel.

Claims

1. A mobile communications system to which high-efficiency coding is utilized between a plurality of mobile stations and a mobile exchange office, comprising:

a plurality of base stations each provided with at least one communications circuit for providing communications with the mobile exchange office;

a circuit switch provided in the mobile exchange office and having a plurality of inputs respectively connected to the corresponding communications circuits of the plurality of base stations, said circuit switch further having a plurality of outputs;

a plurality of high efficiency coder-decoder units provided in the mobile exchange office and being respectively connected to a corresponding one of the plurality of outputs of the circuit switch, wherein a number of said plurality of outputs of said circuit switch is equal to a number of said plurality of high efficiency coder-decoder units; and

a channel switch having a plurality of inputs respectively connected to said plurality of high efficiency coder-decoder units and having an output providing a connection to another communications party, said channel switch setting a communications channel from one of said mobile stations to the another communications party,

wherein when said one of said mobile stations moves from a first region covered by one of said base stations to a second region covered by another of said base stations, said circuit switch provides switching from one of said high efficiency coder-decoder units used for said communications channel to another of said high efficiency coder-decoder units,

wherein said one of said mobile stations is provided with a new communications channel after synchronization between said another of said base stations and said another of said high efficiency coder-decoder units has been established, and wherein said number of said plurality of high efficiency coder-decoder units is less than a number of said plurality of base stations.