Call set-up and spectrum sharing in radio communication on systems with dynamic channel allocation

• US 5,497,505 A
• Filed: 12/17/1993
• Issued: 03/05/1996
• Est. Priority Date: 10/25/1990
• Status: Expired due to Term

• Current Assignee: Bell Canada International, Inc. (BCE Incorporated), Nortel Networks Limited (Nortel Networks Corporation)
• Original Assignee: Bell Canada International, Inc. (BCE Incorporated), Northern Telecom Limited (Nortel Networks Corporation)
• Inventors: Cohn-Sfetcu, Sorin, Lockton, John D., Koohgoli, Mahshad
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): VO, NGUYEN THANH
• Application Number:
  US08/168,173
• Time in Patent Office: 809 Days
• Field of Search: 455/34.1, 455/34.2, 455/33.1, 455/54.1, 455/54.2, 455/56.1, 455/62, 455/63, 455/166.1, 455/166.2, 379/59, 379/62
• US Class Current: 455/452.1
• CPC Class Codes: H04M 1/72511 Searching for available channels
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 72/563 of the wireless resources

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, and which, additionally, are not reserved exclusively for stationary, fixed-allocation services in the geographic location of 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. The technique also facilitates sharing of the radio spectrum with stationary, fixed-allocation services because there is no need to program each subscriber terminal to avoid the spectrum allocated to the fixed service.

Claims

1. In a radio communication system operating within a specified radio spectrum and having a number of base stations, each communicating with a plurality of subscriber terminals over separate radio channels and each base station having access to each of said plurality of radio channels, a method of selecting a radio traffic channel for completing call set-up of incoming and outgoing calls between a base station, a subscriber terminal and a Public Switched Telephone Network (PSTN), said base stations being located in geographical regions wherein varying portions of the radio spectrum in each geographical region are reserved for fixed radio transmission services, the method comprising the steps of:

registering, at each of said base stations, signalling and radio traffic channels that can be allocated, said signalling and radio traffic channels being selected from radio channels covering a radio spectrum lying outside frequencies reserved for fixed radio transmission services in a geographic region of said each of said base stations;

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

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

measuring at the said base station the power level of a scanned traffic channel;

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

sending, to the subscriber terminal, a message indicative of at least one useable traffic channel as determined at the base station;

receiving the message at the subscriber terminal;

switching the said base station and the subscriber terminal to a useable traffic channel indicated in the message; and

proceeding with call connection.

2. In a radio communication system operating within a specified radio spectrum and having a number of base stations, each communicating with a plurality of subscriber terminals over separate radio channels, a method of determining the availability of radio channels for use between said base station and said subscriber terminals, said base stations being located in geographical regions wherein varying portions of the radio spectrum in each geographical region are reserved for fixed radio transmission services, the method comprising the steps of:

selecting a signalling channel for call set-up on a frequency outside a range of frequencies reserved for fixed radio transmission services in a said base station'"'"'s geographical region, said frequency being a frequency that is always available to said system in the said base station'"'"'s geographical region; and

registering, at the said base station associated with the said base station'"'"'s geographical region, radio traffic channels that can be allocated from channels that lie outside the reserved range of frequencies for the said base station'"'"'s geographical region.