# US 5,345,600 A · Method and apparatus for selectively-enabled diversity signaling in a radio communications system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,345,600 A - Document ID: US5345600A - Status: Granted - Kind: A - Application number: 08/114,526 - Filed: 1993-08-31 - Granted: 1994-09-06 - Earliest claimed: 1993-08-31 - Assignees: Motorola, Inc. - Inventors: Allen L. Davidson - Web page: https://patentgrep.com/patent/US5345600A ## CPC - H04L 1/0001: {Systems modifying transmission characteristics according to link quality, e.g. power backoff (adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04)} - H04B 7/02: Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas (RAKE receivers H04B1/7115) - H04B 7/12: Frequency diversity - H04L 1/04: using frequency diversity - H04L 1/0026: {Transmission of channel quality indication} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04B: TRANSMISSION ## Abstract In a radio communications system, a selectively enabled time- and/or frequency-diverse signaling scheme is employed to improve signal quality. In particular, a method of exchanging a message between communication devices using a communications resource might include the step of transmitting a first portion of the message on a first frequency within the communications resource. After determining the quality of the communications resource to be unfavorable, a second portion of the message might be transmitted on the first frequency, and also re-transmitted on a second frequency and/or at a separate time. ## Claims ### Claim 1 In a radio communications system, a method for exchanging a message between a plurality of communication devices using a communications resource, the method comprising the steps of: A) transmitting, from a first of the plurality of communication devices a first portion of the message on a first frequency within the communications resource; B) determining the quality of the communications resource; and C) when the quality of the communications resource is unfavorable, transmitting a second portion of the message on the first frequency and on a second frequency. ### Claim 2 (depends on 1) The method of claim 1, wherein step B) comprises the step of: at the first communication device; B1) calculating a signal quality metric for a signal sent from a second communication device; and B2) transmitting the signal quality metric to the second communication device. ### Claim 3 (depends on 1) The method of claim 1, further comprising the step of: D) identifying a time when the signal-to-noise ratio (SNR) of the first portion of the message falls below a predetermined threshold as being when the quality of the communications resource is unfavorable. ### Claim 4 (depends on 1) The method of claim 1, further comprising the step of: D) identifying a time when the bit error rate (BER) for the first portion of the message falls below a predetermined threshold as being when the quality of the communications resource is unfavorable. ### Claim 5 (depends on 1) The method of claim 1, further comprising the step of: D) transmitting, in response to the step of determining, the second portion of the message on a third frequency. ### Claim 6 In a radio communications system, a method for exchanging a message between a plurality of communication devices using a communications resource, the method comprising the steps of: A) transmitting, from a first of the plurality of communication devices, a first portion of the message at a first time on a first frequency within the communications resource; B) determining the quality of the communications resource; and C) when the quality of the communications resource is unfavorable, transmitting a second portion of the message at a time corresponding to the first time on the first frequency and at a second time on the first frequency. ### Claim 7 (depends on 6) The method of claim 6, wherein step B) comprises the step of: at the first communication device; B1) calculating a signal quality metric for a signal sent from a second communication device; and B2) transmitting the signal quality metric to the second communication device. ### Claim 8 (depends on 6) The method of claim 6, further comprising the step of: D) identifying a time when the signal-to-noise ratio (SNR) of the first portion of the message falls below a predetermined threshold as being when the quality of the communications resource is unfavorable. ### Claim 9 (depends on 6) The method of claim 6, further comprising the step of: D) identifying a time when the bit error rate (BER) for the first portion of the message falls below a predetermined threshold as being when the quality of the communications resource is unfavorable. ### Claim 10 (depends on 6) The method of claim 6, further comprising the step of: D) transmitting, in response to the step of determining, the second portion of the message at a third time on the first frequency. ### Claim 11 (depends on 6) The method of claim 6, wherein the communications resource includes a plurality of time division multiple access (TDMA) frames on the first frequency, and step A) comprises the step of transmitting the second portion of the message in a first timeslot within a first of the plurality of TDMA frames. ### Claim 12 In a radio communications system, a method for exchanging a message between a plurality of communication devices using a communications resource, the method comprising the steps of: A) transmitting, from a first of the plurality of communication devices, a first portion of the message at a first time on a first frequency within the communications resource; B) determining the quality of the communications resource; and C) when the quality of the communications resource is unfavorable, transmitting a second portion of the message at a time associated with the first time on the first frequency and at a second time on a second frequency within the communications resource. ### Claim 13 (depends on 12) The method of claim 12, wherein step B) comprises the step of: at the first communication device; B1) calculating a signal quality metric for a signal sent from a second communication device; and B2) transmitting the signal quality metric to the second communication device. ### Claim 14 (depends on 12) The method of claim 12, further comprising the step of: D) identifying a time when the signal-to-noise ratio (SNR) of the first portion of the message falls below a predetermined threshold as being when the quality of the communications resource is unfavorable. ### Claim 15 (depends on 12) The method of claim 12, further comprising the step of: D) identifying a time when the bit error rate (BER) for the first portion of the message falls below a predetermined threshold as being when the quality of the communications resource is unfavorable. ### Claim 16 (depends on 12) The method of claim 12 wherein the communications resource includes a plurality of time division multiple access (TDMA) frames on the first frequency and a plurality of TDMA frames on the second frequency, and step A) comprises the step of: A1) transmitting the first portion of the message in a first timeslot within a first of the plurality of TDMA frames on the first frequency; and wherein step C) comprises the step of: C1) transmitting the second portion of the message in the first timeslot and in a second timeslot within a second of the plurality of TDMA frames on the second frequency. ### Claim 17 A data transmitter for transmitting a message to a communication device using a communications resource, the communications resource including a plurality of time division multiple access (TDMA) frames on a first frequency and a plurality of TDMA frames on a second frequency, the data transmitter comprising: means for transmitting a first portion of the message in a first timeslot within a first of the plurality of TDMA frames on the first frequency; means for determining the quality of the first timeslot; and means, operably coupled to the means for determining, for transmitting a second portion of the message in the first timeslot and in a second timeslot within a second of the plurality of TDMA frames on the second frequency.