Call set-up in a radio communication system with dynamic channel allocation

• US 5,345,597 A
• Filed: 03/30/1993
• Issued: 09/06/1994
• Est. Priority Date: 10/17/1990
• Status: Expired due to Term

• Current Assignee: Rockstar Bidco LP (Rockstar Consortium Inc.)
• Original Assignee: Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Steer, David G., Plett, Gregory L., Sandler, Howard M., Strawczynski, Leo
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Pham, Chi H.
• Application Number:
  US08/040,395
• Time in Patent Office: 525 Days
• Field of Search: 455/34.1, 455/34.2, 455/54.1, 455/54.2, 455/62, 455/63, 455/67.1, 455/161.3, 455/32.1, 455/53.1, 379/61, 379/63, 340/825.44
• US Class Current: 455/450
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point
• CPC Class Codes: H04W 52/0206 in access points, e.g. base stations access point devices per se H04W88/08
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

The call set-up technique of this invention is characterized by the use of channel information from both base station and subscriber terminal in determining the radio traffic channel upon which to set-up a new call. Communication between the base station and subscriber terminal is carried out on a signalling channel until the traffic channel is chosen. Calls are set-up so that they proceed on the radio channel which, of a set of channels under consideration by the subscriber terminal, contains the least amount of interference as measured at the subscriber terminal. The set of channels under consideration by the subscriber terminal is a subset of the entire set of channels allocated to the service. This subset is comprised of those channels having little interference, as measured by the base station. The call set-up technique thereby assures that calls proceed on channels containing little interference from the viewpoints of both base station and subscriber terminal.

Claims

1. In a radio communication system having a number of base stations, each communicating with a plurality of subscriber terminals over separate traffic channels and each base station having access to each of said plurality of traffic channels, a method of selecting a traffic channel for completing call set-up of incoming and outgoing calls between a base station, a subscriber terminal and the Public Switched Telephone Network (PSTN), comprising the steps of:

receiving, at said base station, an incoming call attempt from a subscriber or from the PSTN;

scanning, at said base station, said plurality of traffic channels for the presence of radio power levels above a first specified threshold;

measuring the power level of a scanned traffic channel;

selecting from the scanned traffic channels, traffic channels with radio power levels below said first specified threshold;

storing a list of selected traffic channels;

sending to the subscriber terminal, along a signalling channel linking the base station and the subscriber terminal, the list of selected traffic channels;

receiving the list at the subscriber terminal;

scanning the traffic channels on the list;

measuring the power level on each scanned traffic channel on said list;

selecting from the scanned traffic channels of the list, traffic channels with radio power levels below a second specified threshold;

storing the traffic channel selection at said subscriber terminal;

sending, to the base station, along the signalling channel, the subscriber terminal'"'"'s traffic channel selection, which provides an indication of the subscriber terminal'"'"'s preferred traffic channel and redundant traffic channel to be selected if the preferred traffic channel becomes unusable;

receiving the traffic channel selection at said base station;

switching the base station and the subscriber terminal to the preferred traffic channel; and

proceeding with call connection.

2. A method as defined in claim 1, wherein of the traffic channels scanned at said base station, only a first number of sequentially scanned traffic channels having radio power levels below said first specified threshold are selected and stored in said list.

3. A method as defined in claim 1, wherein each of said plurality traffic channels are scanned at said base station and only a first number of traffic channels having the lowest radio power levels below said first specified thresholds are selected and stored in said list.

4. A method as defined in claim 1, wherein said plurality of traffic channels are scanned by switching said base station on an available frequency channel using frequency synthesizer means.

5. A method as defined in claim 4, wherein said traffic channels are prescanned prior to call set-up attempt.

6. A method as defined in claim 4, wherein said traffic channels are scanned continuously to maintain a list of useable traffic channels.

7. A method as defined in claim 1, further comprising the step of:

selecting from the scanned traffic channels, traffic channels with radio power levels above said first specified threshold if the number of traffic channels with power levels below said first threshold in insufficient.

8. A method as defined in claim 7, further comprising, at said subscriber terminal, the step of:

selecting from the scanned traffic channels those traffic channels having the lowest radio power levels.