Mobile radio communications system

• US 20020031106A1
• Filed: 10/25/2001
• Published: 03/14/2002
• Est. Priority Date: 04/13/1995
• Status: Active Grant

• Current Assignee: Hitachi Communication Technologies, Ltd. (Hitachi, Ltd.)
• Original Assignee: Kenichi Aoyama, Takeshi Maki, Toshiro Suzuki, Yuji Fukai
• Inventors: Maki, Takeshi, Aoyama, Kenichi, Fukai, Yuji, Suzuki, Toshiro
• Granted Patent: US 6,466,555 B2
• Time in Patent Office: Days
• US Class Current: 370/337
• CPC Class Codes: H04W 36/18 for allowing seamless reselection, e.g. soft reselection
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/324 by mobility data, e.g. speed data
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA

Abstract

A mobile radio communications system having a plurality of base stations accommodating a plurality of mobile stations through radio transmission channels, each of the base stations being connected to a mobile communications exchanger through a plurality of signal lines. Each of the base stations is provided therein with a signal line allocating function unit for selecting a particular signal line from a plurality of signal lines and for allocating a communication slot for a mobile station dominated by the base station at a particular slot position on the selected signal line, a radio channel allocating function unit for allocating a communication slot for the mobile station dominated by the base station at a particular slot position on a radio transmission channel at a particular frequency, and a radio signal delay control unit for performing delay control for a timing at which the base station transmits a radio signal to the mobile station dominated by the base station.

Claims

1. A mobile radio communications system having a plurality of base stations accommodating a plurality of mobile station through radio transmission channels, each said mobile station connected with a mobile communications exchanger through a plurality of signal lines, each of said signal lines parallelly connected to said plurality of base stations, each said base station including a mechanism of selecting a particular signal line from said plurality of signal lines and allocating a communication slot for a mobile station dominated by said base station at a particular slot position on the selected signal line, and a mechanism of allocating a communication slot for the mobile station dominated by said base station at a particular slot position of a radio transmission channel at a particular frequency, wherein:

each said base station autonomously allocates a frequency of a radio transmission channel and a time slot on the radio transmission channel used by a mobile station dominated by said base station, when said mobile station was dominated by an adjacent base station, for said mobile station dominated by said base station, in accordance with a lapse of a fixed time period calculated from a previously assumed moving speed of a moving mobile station under communication;

each said base station allocates a signal line and a communication slot on said signal line used by said mobile station dominated by said base station, when said mobile station was dominated by the adjacent base station, for said mobile station dominated by said base station; and

said moving mobile station sequentially switches a base station to which said moving mobile station is connected, among said plurality of base stations installed along a moving direction of said moving mobile station under communication, without performing a handover operation.

2. A mobile radio communications system according to claim 1, wherein each said base station further comprises radio signal delay control means capable of variably setting a delay time for a transmission timing when each said base station transmits a signal to a mobile station accommodated in an associated radio zone associated with said base station, so that when said respective base stations transmit digital modulated signals to a mobile station, said respective base stations mutually match the phases of their time-division multiplexed channel slots allocated for time-division multiplexed digital modulated signals sent from said respective base stations onto associated radio transmission channels and transmitted to said mobile station.

3. A method of switching a radio zone for a mobile radio communications system having a plurality of base stations accommodating a plurality of mobile station through radio transmission channels, each said mobile station connected with a mobile communications exchanger through a plurality of signal lines, each of said signal lines parallelly connected to said plurality of base stations, each said base station including a mechanism of selecting a particular signal line from said plurality of signal lines and allocating a communication slot for a mobile station dominated by said base station at a particular slot position on the selected signal line, and a mechanism of allocating a communication slot for the mobile station dominated by said base station at a particular slot position of a radio transmission channel at a particular frequency, said method comprising the steps of:

autonomously allocating, in each said base station, a frequency of a radio transmission channel and a time slot on the radio transmission channel used by a mobile station dominated by said base station, when said mobile station was dominated by an adjacent base station, for said mobile station dominated by said base station, in accordance with a lapse of a fixed time period calculated from a previously assumed moving speed of a moving mobile station under communication;

allocating a signal line and a communication slot on said signal line used by said mobile station dominated by said base station, when said mobile station was dominated by the adjacent base station, for said mobile station dominated by said base station; and

sequentially switching a radio zone to which said moving mobile station under communication belongs, without performing a handover operation, when said moving mobile station under communication passes through said plurality of base stations installed along a moving direction of said moving mobile station under communication.

4. A base station for a mobile radio communications system comprising:

an antenna;

a radio signal transmitter/receiver unit;

a modulator/demodulator unit;

a radio signal delay control unit for providing a transmission timing with a delay of a previously set time period when a digital signal received from a mobile communications exchanger and destined to a mobile station dominated by said base station is modulated by said modulator/demodulator unit and transmitted from said radio signal transmitter/receiver unit through said antenna to said mobile station dominated by said base station;

a radio channel allocating function unit for selecting a particular frequency as a radio transmission channel for transmitting and receiving a radio signal to and from a mobile station;

a signal line allocating function unit for selecting a particular signal line from a plurality of signal lines as a signal line for transmitting and receiving a digital signal to and from said mobile communications exchanger and for allocating a communication slot for said mobile station dominated by said base station at a particular slot position on said selected signal line; and

a control unit for generally controlling said radio signal transmitter/receiver unit, said modulator/demodulator unit, said radio signal delay control unit, said radio channel allocating function unit, and said signal line allocating function unit.