Variable bandwidth CDMA radio system

• US 5,128,959 A
• Filed: 02/22/1991
• Issued: 07/07/1992
• Est. Priority Date: 02/22/1991
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Bruckert, Eugene J.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US07/660,192
• Time in Patent Office: 501 Days
• Field of Search: 455/33, 455/38, 455/67, 455/53, 455/54, 379/58, 379/62, 379/59, 379/60, 370/18, 375/1, 380/34
• US Class Current: 370/335
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 7/2631 for broadband transmission
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 72/00 Local resource management
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support

Abstract

A method of identifying a proximal base site of a number of base sites by a communication unit in a CDMA communication system having a number of communication resources. The communication unit identifies the proximal base site by detection and measurement of identification signals received from the base sites where each base site transmits an identification signal containing at least an ID on a communication resource defined by parameters stored within a resource table within a memory unit within the communication unit with such stored parameters including a code key, a bandwidth, and a frequency and wherein at least some resources may be frequency coextensive.

The method includes the steps of selecting a resource from the resource table within the memory of the communication unit and detecting and decoding to produce an ID from a detected identification signal by the communication unit on the resource. The method also includes the step of measuring signal strength by the communication unit of the detected identification signal to produce a magnitude value and storing the value and the ID in a signal strength table within the memory of the communication unit. The communication unit then increments to a next resource within the resource table and repeats the previous steps. The communication unit finally identifies the proximal base site by determining a highest relative signal strength stored within the signal strength table and recovering the ID stored therewith.

Claims

1. In a CDMA communication system having a plurality of communication resources within an allocated frequency spectrum, a method of identifying a proximal base site of a plurality of base sites by a communication unit through detection and measurement of identification signals received from at least some of the plurality of base sites on the plurality of communication resources where each base site transmits an identification signal containing at least an ID on a dedicated resource of the plurality of resources with each resource of the plurality of resources defined by parameters stored within a resource table in a memory unit with the communication unit and base sites with such stored parameters of each resource including a code key of a plurality of code keys, a bandwidth of a plurality of bandwidths, and a frequency of a plurality of frequencies and where at least some resources of the plurality of resources may, be frequency coextensive, such method including the steps of:

A) selecting a resource from the resource table within the memory of the communication unit;

B) detecting, and decoding to produce an ID from a detected identification signal by the communication unit on the resource;

C) measuring signal strength by the communication unit of the detected identification signal to produce a magnitude value and storing the value and the ID in a signal strength table within the memory of the communication unit;

D) incrementing to a next resource within the resource table;

E) repeating setps A-D with remaining resources within the resource table;

F) identifying the proximal base site by determining a highest relative signal strength value stored within the signal strength table and recovering the ID stored therewith.

2. The method as in claim 1 further including the step of selecting a communication resource by application of an algorithm for identifying communication resources between a lowest and a highest frequency in an allocated spectrum using a multiple of a base bandwidth and a code key table.

3. In a CDMA communication system having a plurality of comunication resources within an allocated frequency spectrum, an apparatus for identifying a proximal base site of a plurality of base sites by a communication unit through detection and measurement of identification signals received from at least some of the plurality of base sites on the plurality of communication resources where each base site transmits an identification signal containing at least an ID on a dedicated resource of the plurality of resources with each resource of the plurality of resources defined by parameters stored within a resource table in a memory unit within the communication unit and base sites with such stored parameters of each resource including a code key of a plurality of code keys, a bandwidth of a plurality of bandwidths, and a frequency of a plurality of frequencies and where at least some resources of the plurality of resources may, be frequency coextensive, such apparatus comprising

A) means for selecting a resource from the resource table within the memory of the communication unit;

B) means for detecting, and decoding to produce an ID from a detected identification signal by the communication unit on the resource;

C) means for measuring signal strength by the communication unit of the detected identification signal to produce a magnitude value and storing the value and the ID in a signal strength table within the memory of the communication unit;

D) means for incrementing to a next resource within the resource table;

E) means for repeating steps A-D with remaining resources within the resource table

F) means for identifying the proximal base site by determining a highest relative signal strength value stored within the signal strength table and recovering the ID stored therewith.

4. The apparatus as in claim 3 further including means for identifying communication resources between a lowest and a highest frequency in an allocated spectrum using a multiple of a base bandwidth and a code key table.

5. In a CDMA communication system having a plurality of communication resources within an allocated frequency spectrum having a lowest and a highest frequency, a plurality of base sites having transmitters, at least one of which transmits an identification signal on a communication resource of the plurality of communication resources for the benefit of an at least one communication unit for identification of a proximal base site through detection of the identification signal, with the plurality of communication resources having an at least first group of communication resources defined by a plurality of code keys, a group bandwidth, with the first group bandwidth defined to be a base bandwidth and subsequent group bandwidth to be twice previous group bandwidth, and an at least first frequency group, with the first frequency in each group being one-half group bandwidth above the lowest frequency of the allocated frequency spectrum and remaining group frequencies in incremental steps of one group bandwidth above the first frequency in the group up to a frequency one-half group bandwith below the highest frequency in the allocated spectrum, a method of identifying a proximal base site of the plurality of base sites by the at least one communication unit, such method including the steps of:

A) selecting a resource having a lowest frequency and narrowest group bandwidth in the at least first group of communication resources from a resource table within a memory unit within communication unit;

B) decoding the information signal by the communication unit using a code key of the plurality of code keys entered into a code key table within the memory;

C) measuring signal strength and storing magnitude in a proximal base site storage table within the memory upon detection of the information signal;

D) incrementing code keyws within the code key table;

E) repeating steps B through the present step with the remaining code key within the code key table;

F) incrementing to the next comunication resource wihtin the at least first group of communication resources within the at least first group of communication resources;

G) repeating steps B through the present step until the group bandwidth equals the allocated frequency spectrum; and

,

H) identifying the communication resource within the proximate base site storage table having the highest relative strength measurement magnitude as from the proximal base site.

6. The method as in claim 5 further including the step of selecting a communication resource by application of an algorithm for identifying communication resources between a lowest and a highest frequency in an allocated spectrum using a mulitple of a base bandwidth and a code key table.

7. In a CDMA communication system having a plurality of communication resources within a allocated frequency spectrum having a lowest and a highest frequency, a plurality of base sites having transmitters, at least one of which transmits an identification signal on a communication resource of the plurality of communication resources for the benefit of an at least one communication unit for identification of a proximal base site through detection of the identification signal, with the plurality of communication resources having an at least first group of communication resources defined by a plurality of code keys, of group bandwidth, with the first group bandwidth defined to be a base bandwidth and subsequent group bandwidth to be twice previous group bandwidth, and an at least first frequency group, with the first frequency in each group being one-half group bandwidth above the lowest frequency of the allocated frequency spectrum and remaining group frequencies in incremental steps of one group bandwidth above the first frequency in the group up to a frequency one-half group bandwidth below the highest frequency in the allocated spectrum, an apparatus for identifying a proximal base site of the plurality of base sites by the at least one communication unit, such apparatus comprising:

A) means for selecting a resource having a lowest frequency and narrowest group bandwidth in the at least first group of communication resource from a resource table within a memory unit within the communication unit;

B) means for decoding the information signal by the communication unit using a code key of the plurality of code keys entered into a code key table within the memory;

C) means for measuring signal strength and storing magnitude in a proximal base site storage table within the memory upon detection of the information signal;

D) means for incrementing code keys within the code key table;

E) means for repeating steps B through the present step with the remaining code keys within the code key table;

F) means for incrementing to the next communication resource within the at least first group of communication resources;

G) means for repeating steps B through the present step until the group bandwidth equals the allocated frequency spectrum; and

,

H) means for identifying the communication resource within the proximate base site storage table having the highest relative strength measurement magnitude as from the proximal base site.

8. The apparatus as in claim 7 further including means for identifying communication resources between a lowest and a highest frequency in an allocated spectrum using a multiple of base bandwidth and a code key table.

9. In a CDMA communication system having a plurality of communication resources within an allocated frequency spectrum a plurality of base sites having transmitters, at least one of which transmits an identification signal on a communication resource of the plurality of communication resources for the benefit of an at least one communication unit for identification of a proximal base site for hand-off of a communication transaction on a home resource from a home base site to the proximal base site through detection of the identification signal from the proximal base site, with the plurality of communication resources having an at least first group of resources defined by a plurality of code keys, an at least first group bandwidth and an at least first group of frequencies, a method for achieving hand-off between base sites having a plurality of bandwidths, such method including the steps of:

A) identifying a proximal base site having a group bandwidth through a suitable algorithm comparing signal strengths;

B) comparing home base site signal bandwidth with the group bandwidth of the proximal base site and, upon occasion, determining that the home site bandwidth is larger than proximal base site group bandwidth and transmitting a request to a home site resource controller requesting the home site bandwidth be reduced to the proximal base site group bandwidth thereby defining a new home resource; and

C) achieving hand-off by transmitting a resource request to the proximal base site requesting access to the communication transaction through the proximate base site on the home communication resource.

10. In a CDMA communication system having a plurality of communication resources within an allocated frequency spectrum, a plurality of base sites having transmitters, at least one of which transmits an identification signal on a commmunication resource of the plurality of communication resources for the benefit of an at least one communication unit for identification of a proximal base site for hand-off of a communication transaction on a home resource from a home base site to the proximal base site through detection of the identification signal from the proximal base site, with the plurality of communication resources having an at least first group of resources defined by a plurality of code keys, an at least first group bandwidth and an at least first group of frequencies, an apparatus for achieving hand-off between base sites having a plurality of bandwidths, such apparatus comprising:

A) means for identifying a proximal base site having a group bandwidth through a suitable algorithm comparing signal strengths;

B) means for comparing home base site signal bandwidth with the group bandwidth of the proximal base site and, upon occasion, determining that the home site bandwidth is larger than proximal base site group bandwidth and transmitting a request to a home site resource controller requesting the home site bandwidth be reduced to the proximal base site group bandwidth thereby defining a new home resource; and

C) means for achieving hand-off by transmitting a resource request to the proximal base site requesting access to the communication transaction through the proximate base site on the home communication resource