# US 5,345,469 A · Communication device with code sequence selection system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,345,469 A - Document ID: US5345469A - Status: Granted - Kind: A - Application number: 08/011,581 - Filed: 1993-02-01 - Granted: 1994-09-06 - Earliest claimed: 1993-02-01 - Assignees: Motorola, Inc. - Inventors: Tracy L. Fulghum - Web page: https://patentgrep.com/patent/US5345469A ## CPC - H04J 13/16: Code allocation - H04B 1/707: using direct sequence modulation - H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S) - H04B: TRANSMISSION ## Abstract A code division multiple access (CDMA) communication system (10) having a plurality of spreading codes including a control code includes a first communication device (100) and a second communication device (106). The first communication device is adapted for transmitting a signal spread by the control code inclusive of a request for an optimum spreading code. The second communication device (106) includes a receiver (202) and an adaptable match filter (204) for identifying the optimum spreading code. A transmitter (2024) transmits information about the spreading code to the first communication device 100. With the information on the optimum spreading code available, the first communication device (100) and the second communication device (106) continue to communicate with each other. The optimum spreading code is periodically updated by the first communication device (100) and second communication device (106) to provide for changes in the utilization of codes. ## Claims ### Claim 1 A Code Division Multiple Access (CDMA) communication system for reuse of available spreading codes, the system having a control spreading code and comprising: a first communication device for transmitting a first signal spread by the control spreading code, the first signal includes a request for a first spreading code; a second communication device, including: a receiver for receiving the first signal; means for identifying the first spreading code determined to be optimum for the reception of signals by the second communication device; and a transmitter for transmitting the identity of the first spreading code to the first communication device; whereby the first communication device communicates with the second communication device using the first spreading code. ### Claim 2 (depends on 1) The communication system of claim 1, wherein the first and second communication devices include Direct Sequence Code Division Multiple Access (DSCDMA) communication devices. ### Claim 3 (depends on 1) The communication system of claim 1, wherein the means for identifying identifies a plurality of spreading codes optimum for the reception of signals by the second communication device. ### Claim 4 (depends on 3) The communication system of claim 3, wherein the first communication device selects one of the plurality of spreading codes to communicate with the second communication device. ### Claim 5 (depends on 1) The communication system of claim 1, wherein the transmitter includes a controller for requesting a code that is optimum for the first communication device. ### Claim 6 (depends on 1) The communication system of claim 1, wherein the first communication device includes means for identifying a second spreading code optimum for the first communication device. ### Claim 7 (depends on 1) The communication system of claim 1, wherein the first communication device includes means for periodically checking for optimum codes and communicating them to the second communication device. ### Claim 8 (depends on 1) The communication system of claim 1, wherein the second communication device includes means for periodically checking for optimum codes and communicating them to the first communication device. ### Claim 9 In a DSCDMA communication system having at least a first and a second communication device, a method for providing communication between the first and the second communication devices with optimum reuse of spreading codes, comprising the steps of: in the first communication device: transmitting a signal to the second communication device requesting a first spreading code; in the second communication device: receiving the signal; identifying a first spreading code determined to be optimum for the reception of signals by the second communication device; transmitting information about the first spreading code to the first communication device; and receiving signals from the first communication device spread by the first spreading code. ### Claim 10 (depends on 9) The method of claim 9, further including the step of: in the first communication device, identifying a second spreading code optimum for the first communication device. ### Claim 11 (depends on 10) The method of claim 10, further including the step of: in the first communication device, transmitting the second spreading code. ### Claim 12 (depends on 9) The method of claim 9, further including the step of: in the second communication device, receiving the second spreading code and communicating with the first communication device using the second spreading code. ### Claim 13 (depends on 9) The method of claim 9, further including the step of: periodically updating the first and second spreading codes. ### Claim 14 (depends on 13) The method of claim 13, further including the step of: the first and the second communication devices communicating the updated spreading codes to each other as they are updated. ### Claim 15 (depends on 13) The method of claim 13, further including the step of: the first and the second communication devices communicating with each other using the updated spreading codes. ### Claim 16 (depends on 9) The method of claim 9, wherein the step of identifying identifies a plurality of spreading codes optimum for the second communication device. ### Claim 17 (depends on 16) The method of claim 16, further including the step of: in the first communication device, identifying which of the plurality of spreading codes is optimum to communicate with the second communication device. ### Claim 18 A CDMA communication device having a control code, comprising: a receiver for receiving a signal coded with the control code from a communication unit, the signal including a request for a first spreading code; means for identifying the first spreading code determined to be optimum for the reception of signals by the receiver; a transmitter for transmitting information about the first spreading code; and the receiver includes means for receiving and decoding signals spread by the first spreading code. ### Claim 19 (depends on 18) The receiver of claim 18, further including an adaptable matched filter. ### Claim 20 (depends on 18) The receiver of claim 18, wherein the means for identifying includes means for periodically searching for optimum spreading codes.