Portable radio telephone system

• US 4,790,000 A
• Filed: 12/10/1986
• Issued: 12/06/1988
• Est. Priority Date: 12/11/1985
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kinoshita, Yasuaki
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/940,489
• Time in Patent Office: 727 Days
• Field of Search: 379/61, 379/59, 379/60, 379/57, 379/62, 379/63, 379/58, 455/33, 455/56, 455/54, 455/58
• US Class Current: 455/449
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

In order to make it possible to communicate between a portable radio telephone set through an existing public cellular radio telephone system and a private radio telephone system disposed inside the cells of the public cellular radio telephone system, an antenna and a transceiver for connecting the antenna to the private radio telephone system are disposed in each cell, and the transmitting power from the antenna and the transmitting power from the portable telephone set are set so that they do not impart interference waves to the public cellular radio telephone system.

Claims

1. In a portable radio telephone system for use in a given area which is divided into a plurality of large areas, each of said large areas being further divided into a plurality of small cellular areas, wherein the same radio frequency channels are repeated for each of said large areas, while respective ones of said radio frequency channels are allocated to said respective small cellular areas in each large area, a system for effecting radio communication by means of a portable radio telephone set by use of selected ones of said allocated frequency channels, comprising:

a plurality of antennas provided in a local area disposed inside one of said small cellular areas for transmitting and receiving radio waves;

a portable radio telephone set;

a private branch exchange disposed within said local area; and

a transmission/reception circuit connecting said antennas to said private branch exchange;

wherein radio communication is carried out inside said local area by said portable radio telephone set by use of radio waves of one of said allocated frequency channels of a non-adjacent small cellular area which is different from the frequency channel allocated to the small cellular area in which said local area is disposed and the power of said radio waves used by said portable radio telephone set in said local area is larger than the power of radio waves of the same frequency radiated from small cellular areas other than said small cellular area in which said local area is disposed.

2. A portable radio telephone system according to claim 1, wherein said local area lies within a building structure.

3. A portable radio telephone system according to claim 2, wherein a plurality of antennas is disposed inside said building structure and frequency channels different from said frequency channels allocated to said small cellular area in which said local area is disposed are used for radio communication inside said building structure.

4. A portable radio telephone system according to claim 2, wherein said local area disposed in one of said small cellular areas consists of a plurality of mini areas, and said antennas are disposed in said mini areas adjacent to one another and transmit and receive radio waves of mutually different frequencies.