Cellular mobile communication system wherein service area is reduced in response to control signal contamination

• US 5,815,818 A
• Filed: 04/20/1992
• Issued: 09/29/1998
• Est. Priority Date: 04/19/1991
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Tanaka, Shoji, Tsuji, Toshiya
• Primary Examiner(s): Saras, Steven J.
• Assistant Examiner(s): Shankar, Vijay
• Application Number:
  US07/870,982
• Time in Patent Office: 2,353 Days
• Field of Search: 455/127, 455/343, 455/63, 455/69, 455/67.3, 455/38.3, 455/422, 455/517, 455/522, 455/574
• US Class Current: 455/522
• CPC Class Codes: H04W 16/06 Hybrid resource partitioning, e.g. channel borrowing

Abstract

In order to facilitate communications in a cellular communication system wherein control signal contamination renders communication with the closest cell impossible, the transmission power of the closest cell is reduced to the point wherein communication between the mobile unit and a cell adjacent the closest one, is enabled.

Claims

1. A method of controlling service area size of a given cell in response to control channel signal contamination being detected at a base station of said given cell in a cellular mobile communications system, comprising the steps of:

sensing the control channel signal contamination which inhibits communication between a mobile unit and a transceiver of the base station;

detecting the contaminated control channel signal level; and

reducing the transmission power of the transceiver of the base station, in response to the contaminated control channel signal level, to a level whereat communication between a base station of a cell adjacent to said given cell and the mobile unit is enabled.

3. A method as set forth in claim 1, wherein the step of reducing the transmission power of the transceiver of the base station is executed discretely in response to the contaminated control channel signal level.

2. A cellular mobile communications system, comprising:

means for sensing control channel signal contamination which inhibits communication between a mobile unit and a transceiver of a base station of a given cell which forms part of said cellular mobile communications system;

means for detecting the contaminated control channel signal level; and

means for reducing the transmission power of the transceiver of the base station, in response to the contaminated control signal level, to a level whereat communication between a base station of a cell adjacent to said given cell and the mobile unit is enabled.

4. A cellular mobile communications system having a plurality of cells, each cell containing a base station comprising a base station controller, a control channel transceiver, and a plurality of voice channel transceivers, the control channel transceiver of the base station of at least one of the plurality of cells comprising:

a duplexing unit, receiving a call request signal from an antenna and sending said call request signal to a receiving unit which converts said call request signal to an intermediate frequency;

a demodulating unit, receiving said converted call request signal, and producing a demodulated signal;

a signal strength detecting unit, receiving said converted call request signal, and producing a signal strength indication signal corresponding to the signal strength of said converted call request signal; and

a contaminated signal discriminating unit, passing said demodulated signal to said base station controller if said demodulated signal contains a predetermined seizure precursor, and passing said signal strength indication signal to said base station controller if said demodulated signal does not contain said predetermined seizure precursor,

wherein said base station controller reduces a transmission power of said control channel transceiver in response to said signal strength indication signal.