Code division multiple access (CDMA) inbound messaging system utilizing re-use of sequences

• US 5,761,196 A
• Filed: 11/14/1994
• Issued: 06/02/1998
• Est. Priority Date: 01/13/1993
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Douglas I. Ayerst, Stephen R. Carsello, Warren P. Glotzbach
• Inventors: Ayerst, Douglas I., Carsello, Stephen R., Glotzbach, Warren P.
• Primary Examiner(s): TSE, YOUNG TOI
• Application Number:
  US08/339,443
• Time in Patent Office: 1,296 Days
• Field of Search: 375/200, 375/206, 375/208, 340/825.44, 455/33.1, 455/49.1, 455/51.1, 455/53.2, 455/54.2, 455/56.1, 455/422, 455/465, 455/500, 455/502, 455/507, 455/525, 370/320, 370/329, 370/335, 370/342
• US Class Current: 370/335
• CPC Class Codes: H04J 13/16 Code allocation
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 16/12 Fixed resource partitioning
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A central controller (10) controls the operation of a code division multiple access (CDMA), spread spectrum communication system, which includes base stations (15) and portable transceivers (20) for communicating with the base stations (15). The central controller (10) stores a plurality of seeds, which are used by the portable transceivers (20) in generating pseudo-noise (PN) sequences, and, in response to requests from base stations (15), the central controller (10) distributes at least a portion of the assignable seeds to each of the requesting base stations (15). The base stations (15) that have received seeds from the central controller (10) subsequently transmit the seeds over the air to the portable transceivers (20) within their respective coverage areas. The portable transceivers (20) then utilize the seeds to generate spread spectrum signals for reception by a closest base station (15) having a coverage area in which they are located.

Claims

1. A method for distributing at least a portion of a plurality of seeds which are used by pseudo-noise (PN) generators to spread and despread spread spectrum signals in a spread spectrum code division multiple access (CDMA) communication system comprising base stations for communicating with portable transceivers, the communication system further comprising a central controller having a memory for storing the plurality of seeds in a database and a processing unit for controlling operation of the base stations and distribution of the at least a portion of the plurality of seeds to the bases stations via a data port, the method comprising the steps of:

at the central controller

(a) receiving a seed request from a first base station coupled to the central controller by the data port,

(b) determining which of the plurality of seeds stored in the database are available seeds that are used for communication between the first base station and one or more portable transceivers within an associated coverage area thereof without interfering with other base stations within the communication system, and

(c) providing a subset of the available seeds to the data port for transfer to the first base station; and

at the first base station

(d) subsequently transmitting the subset of the available seeds to the one or more portable transceivers for use in generating uniquely identifiable spread spectrum signals for reception by the first base station.

2. The method in accordance with claim 1, wherein the base stations are grouped into a plurality of re-use groups and step (b) comprises the steps of:

at the central controller

(b1) determining, by reference to the database, which of the plurality of seeds are tagged in memory to indicate that they have been provided to another requesting base station, wherein the tagged seeds represent assigned seeds and other seeds of the plurality of seeds that have not been tagged represent unassigned seeds that are not currently in use by any of the base stations; and

further

(b2) determining, by reference to the database, whether any of the assigned seeds have been provided to a second base station, which is included in any of the plurality of re-use groups different than that of the first base station,

wherein communications within the coverage area of the first base station will not interfere with communications within the coverage area of the second base station, and wherein the assigned seeds that have been provided to the second base station and the unassigned seeds comprise the available seeds which are to be provided to the first base station for use in communications in the coverage area thereof without interfering with the other base stations in the communication system.

3. The method in accordance with claim 1, further comprising the step of:

at the central controller, and subsequent to step (c),

(e) tagging the subset of the available seeds in the database as to indicate that the tagged subset has been provided to the first base station.

4. The method in accordance with claim 3, further comprising the steps of:

at the first base station, when a seed included in the subset of the available seeds provided thereto is no longer in use,

(f) transmitting a signal to the data port of the central controller indicating that the seed is no longer in use; and

at the central controller, in response to step (f),

(g) tagging the seed in the database to indicate that the seed is not currently in use by the first base station.

5. A central controller for distributing a plurality of seeds stored by the central controller to base stations for transmission therefrom to portable transceivers which have pseudo-noise (PN) generators which use the plurality of seeds to generate and transmit spread spectrum signals which are received by the base stations, wherein the central controller, base stations, and portable transceivers are included in a code division multiple access (CDMA) communication system, the central controller comprising:

a database for storing the plurality of seeds;

a data port for receiving a seed request from a first of the base stations; and

a processing unit, coupled to the database and the data port, for determining by reference to the database, which, if any, of the plurality of seeds are suitable for utilization by one or more portable transceivers located within the coverage area of the first base station without interfering with other base stations in the communication system, and for retrieving from the database one or more of the plurality of seeds that are to be utilized by the one or more portable transceivers located within the coverage area of the first base station without interfering with the other base stations, wherein the retrieved seeds are provided to the data port for subsequent transmission therefrom to the first base station.

6. The central controller in accordance with claim 5, further comprising tagging means for tagging, in the database, each of the ones of the plurality of seeds provided to the first base station to indicate that the tagged ones of the plurality of seeds are currently in use by the first base station.

7. The central controller in accordance with claim 6, further comprising a telephone interface which is coupled to the processing unit for receiving messages and a message buffer coupled to the telephone interface for temporarily storing the messages which are received.

8. The central controller in accordance with claim 7, wherein the processing unit automatically provides a unique seed included in the plurality of seeds to the data port for subsequent transmission therefrom to each of the base stations in the communication system, wherein each of the base stations transmits its unique seed for utilization by a portable transceiver in the coverage area thereof to generate a spread spectrum signal indicating to a closest base station that the portable transceiver is in the coverage area thereof.

9. A spread spectrum, code division multiple access (CDMA) communication system for providing two-way communication, the communication system comprising:

base stations for receiving spread spectrum signals over the air and for generating seed requests depending upon the number of received spread spectrum signals; and

a central controller, coupled to and controlling the base stations and having a memory in which a plurality of seeds are stored, the plurality of seeds are used by pseudo-noise (PN) generators within the base stations for generating PN sequences for despreading signals which have been spread using the plurality of seeds by pseudo-random noise (PN) generators within portable transceivers the central controller selectively distributing a portion of the plurality of seeds to each of the base stations in accordance with the seed requests.

10. The communication system in accordance with claim 9, wherein:

the central controller comprises determining means for determining, for each base station from which a seed request was received, which one of the plurality of seeds are suitable for utilization in spread spectrum communication within the coverage area of that base station without interfering with other base stations in the communication system.

11. The communication system in accordance with claim 10, further comprising at least one portable transceiver for communicating with a closest base station, the at least one portable transceiver utilizing at least one of the portion of the plurality of seeds provided to the closest base station to generate spread spectrum signals uniquely associated with the closest base station.

12. The communication system in accordance with claim 11, wherein:

the base stations are grouped into re-use groups including first and second base stations, located in different re-use groups, that utilize same portion of the plurality of seeds for spread spectrum communication without interfering with each other or with other base stations in the communication system.

13. A communication system for providing two-way spread spectrum, code division multiple access (CDMA) communication, the communication system comprising:

a portable transceiver for using a pseudo-noise (PN) generator to generate spread spectrum signals using at least one seed;

base stations for transmitting and receiving spread spectrum signals, wherein a first of the base stations provides the portable transceiver with the at least one seed and receives the spread spectrum signals generated by the portable transceiver; and

a central controller coupled to and controlling the base stations, the central controller comprising;

memory means for storing a plurality of seeds, including the at least one seed provided to the portable transceiver by the first base station, for use in spread spectrum communication;

determining means for determining which one of the base stations, other than the first base station, is a second base station, wherein communications between the first base station and the portable transceiver will not interfere with communications within the coverage area of the second base station when the second base station also utilizes the at least one seed provided to the first base station; and

processing means coupled to the memory means for also providing the at least one seed to the second base station for use thereby in spread spectrum communication.