Fixed wireless access system and apparatus therefor

• US 6,731,905 B2
• Filed: 03/09/2001
• Issued: 05/04/2004
• Est. Priority Date: 09/11/2000
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Doi, Nobukazu, Ogino, Atsushi, Ishifuji, Tomoaki, Suzuki, Hideya
• Primary Examiner(s): Appiah, Charles
• Assistant Examiner(s): Ly, Nghi H.
• Application Number:
  US09/801,728
• Publication Number:
  US 20020032031A1
• Time in Patent Office: 1,152 Days
• Field of Search: 455/7, 455/11.1, 455/561, 455/562, 455/554.2, 455/435.1, 455/435.2, 455/435.3, 455/13.1, 455/16, 342/81, 342/90, 342/353, 342/357.1, 342/359, 342/360
• US Class Current: 455/11.1
• CPC Class Codes: H04B 7/155 Ground-based stations H04B7/204 takes precedence

Abstract

In a P-MP fixed wireless access system using quasi-millimeter and millimeter wave bands, a relaying path is autonomously set up for subscriber stations without the need for additional provision of a repetition radio circuit using a costly MMIC. A subscriber station in the fixed wireless access system is provided with a repeating function for relaying signals between a different subscriber station and a base station, a buffer memory for temporarily storing signals to be communicated therebetween, and a table for registering information for identifying a relaying path between an own reference wireless station and a lower-level subscriber station for signal repetition. The base station is provided with a table in which, in order to perform signal communication with an arbitrary subscriber registered in the base station, routing information is registered for determining whether or not to set up a relaying path via a different subscriber station registered in the base station.

Claims

1. In a fixed wireless system based on a time-division multiple-access scheme in which a plurality of subscriber stations carry out communication via a base station using a signal frame having a control channel, a communication channel and a reservation channel, each of said subscriber stations comprising:

a radio circuit capable of transmitting and receiving signals at the same frequency through an antenna;

a communication controller, connected with said radio circuit, for identifying an incoming signal, for generating an outgoing signal, and for managing radio channels;

a buffer memory for temporarily storing signals to be communicated between a different subscriber station and said base station;

a first table for registering information on a wireless station which serves as a clock supplier for said subscriber station and for registering routing information for identifying a relaying path to a lower-level subscriber station for signal repetition via said subscriber station; and

a third table for recording a frame format;

wherein said communication controller comprises means for judging whether or not signal repetition is needed for communication between a different subscriber station and said base station, and means for automatically establishing a relaying path if it is judged that signal repetition is needed.

2. A subscriber station as claimed in claim 1, further comprising a receiving quality monitor for measuring reception quality of said incoming signal.

3. A subscriber station as claimed in claim 1, in which said communication controller comprises antenna management means for managing an antenna section used for transmitting and receiving signals, said antenna section comprises an antenna selector for making antenna selection according to a selection signal issued from said antenna management means and a plurality of directional antennas having respective directivities to different orientations, and said first table is provided for registering information on wireless station which serves as a clock supplier for said subscriber station when each of said plural directional antennas is used and for registering routing information for identifying a relaying path to a lower-level subscriber station for signal repetition via said subscriber station.

4. A subscriber station as claimed in claim 1, further comprising a timer section for indicating the upper limit of a period of searching for a wireless station serving as a clock supplier and the upper limit of a period of searching for a lower-level subscriber station to be connected with said subscriber station.

5. A subscriber station as claimed in claim 4, in which said communication controller comprises antenna management means for managing an antenna section used for transmitting and receiving signals, said antenna section comprises an antenna selector for making antenna selection according a selection signal issued from said antenna management means and a plurality of directional antennas having respective directivities to different orientations, and said first table is provided for registering information on wireless station which serves as a clock supplier for said subscriber station when each of said plural directional antennas is used and for registering routing information for identifying a relaying path to a lower-level subscriber station for signal repetition via said subscriber station,

wherein said timer section comprises a first timer for indicating the upper limit of a period of searching for a wireless station serving as a clock supplier and a second timer for indicating the upper limit of a period of searching for a lower-level subscriber station to be connected with said subscriber station, and the upper limit of a period of searching for said lower-level subscriber station which is indicated by said second timer has a value greater than or equal to the product in multiplication of “ the upper limit of a period of searching for said wireless station serving as a clock supplier which is indicated by said first timer”

by “

the maximum number of directional antennas equipped on said subscriber station”

.

6. An access method for a fixed wireless access system in which a plurality of subscriber stations carry out communication via a base station using a signal frame having a control channel, a communication channel and a reservation channel, said access method comprising the steps of:

allowing at least one of said plural subscriber stations to be synchronized with said fixed wireless access system via said base station or a different subscriber station serving as a repeater in said fixed wireless access system;

performing, from said subscriber station synchronized with said system, registration to an own reference wireless station thereof;

checking, at said subscriber station synchronized with said system, whether or not to set up a relaying path;

relaying, at said different subscriber station serving as a repeater, a control channel signal received from an own reference wireless station thereof to an own lower-level subscriber station thereof;

receiving, at said different subscriber station serving as a repeater, registration or repetition of registration from a different subscriber station for which said different subscriber station serving as a repeater is used as a reference wireless station, and transmitting, from said different subscriber station serving as a repeater, said registration or said repetition of registration to an own reference wireless station thereof;

relaying, at said different subscriber station serving as a repeater, origination from or termination to an own lower-level subscriber station thereof, and relaying, at said different subscriber station serving a repeater, a communication channel signal between aid base station and said lower-level subscriber station;

receiving, at said different subscriber station serving as a repeater, control channel reservation or repetition of control channel reservation from an own lower-level subscriber station thereof, and transmitting, from said different subscriber station serving as a repeater, said control channel reservation or said repetition of control channel reservation to an own reference wireless station thereof;

receiving, at said different subscriber station serving as a repeater, notification of the end of control channel use or repetition of notification of the end of control channel use from an own lower-level subscriber station thereof, and transmitting, from said different subscriber station serving as a repeater, said notification of the end of control channel use or said repetition of notification of the end of control channel use to an own reference wireless station thereof;

receiving, at said subscriber station synchronized with said system, termination to itself, processing origination from itself, and making re-registration in an own reference wireless station thereof;

monitoring, at said subscriber station synchronized with said system, a control channel signal transmitted from a wireless station different from an own reference wireless station thereof, and according to the result of said monitoring, making a changeover from said own reference wireless station to said different wireless station;

accepting, at said base station, registration or repetition of registration from a subscriber station;

allocating, at said base station, a control channel to a subscriber station;

deallocating, at said base station, a control channel thus allocated; and

processing, at said base station, origination from or termination to a subscriber station.