# US 7,609,712 B2 · Frequency offset differential pulse position modulation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,712 B2 - Document ID: US7609712B2 - Status: Granted - Kind: B2 - Application number: 11/504,967 - Filed: 2006-08-15 - Published: 2007-05-17 - Granted: 2009-10-27 - Earliest claimed: 1999-02-08 - Inventors: John B. Langley; Michael Mancusi - Web page: https://patentgrep.com/patent/US7609712B2 ## CPC - H04W 16/14: Spectrum sharing arrangements {between different networks} - H04B 14/026: {using pulse time characteristics modulation, e.g. width, position, interval} - H04B 14/066: {using differential modulation with several bits [NDPCM]} - H04L 1/1685: {the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal} - H04L 1/188: {Time-out mechanisms} - H04L 5/06: the signals being represented by different frequencies (combined with time-division multiplexing H04L5/26) - H04L 25/4902: {Pulse width modulation; Pulse position modulation} - H04L 27/2601: {Multicarrier modulation systems} - H04L 1/1887: {Scheduling and prioritising arrangements} - H04W 36/06: Reselecting a communication resource in the serving access point - H04W 84/18: Self-organising networks, e.g. ad-hoc networks or sensor networks - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04B: TRANSMISSION - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract The present invention provides such a need by utilizing a frequency offset differential pulse position modulation scheme to transmit data between computing devices within a wireless network system. The differential pulse position modulation component of the scheme enables the present invention to provide relative immunity to interference for the system. In particular, such immunity from interference is achieved by utilizing a blanking time between pulse positions, which is large enough to allow the interference between frequency offset—differential pulse position modulation pulses to subside. The frequency offset component of the scheme enables the system to utilize multiple frequency channels to enable the system to achieve higher data rates. In particular, by utilizing a time offset between the frequency channels, the blanking time can be reduced, thereby increasing the amount of data that can be transmitted with a set period of time. ## Claims ### Claim 1 A method for controlling access to a medium comprising: (a) determining a first transmit time for a packet on a transmission medium based on a non-zero number selected from a random number generator; (b) at the determined first transmit time, sensing traffic on said transmission medium; (c) if said transmission medium is available, transmitting the packet; and (d) if said transmission medium is not available, deferring a transmission of the packet to a second transmit time using a second non-zero number selected from the random number generator. ### Claim 2 (depends on 1) The method of claim 1, wherein said second transmit time is further based at least in part on an Inter Packet Gap time. ### Claim 3 (depends on 1) The method of claim 1, further comprising counting a number of instances said transmission of the packet is deferred and deferring said transmission until the number of instances said transmission is deferred reaches a threshold value. ### Claim 4 (depends on 3) The method of claim 3 further comprising: terminating attempts to transmit the packet based, at least in part, on the number of instances of said transmission reaching said threshold value. ### Claim 5 (depends on 1) The method of claim 1 wherein said second transmit time is further based at least in part on a back-off process in response to said deferral of transmission. ### Claim 6 (depends on 1) The method of claim 1 wherein said second transmit time is further based at least in part on multiplying the second non-zero number by a programmable access-slot time. ### Claim 7 (depends on 6) The method of claim 6 wherein the programmable access-slot time is determined based on a round trip delay time between any sending and receiving pair of nodes accessing the transmission medium. ### Claim 8 (depends on 6) The method of claim 6 wherein the programmable access-slot time includes a transmit turn-on time. ### Claim 9 (depends on 1) The method for of claim 1, wherein a maximum number selectable from the random number generator is determined based on a counter of a number of instances said transmission of the packet is deferred. ### Claim 10 (depends on 5) The method of claim 5 wherein the back-off process is a linear back-off process. ### Claim 11 (depends on 1) The method of claim 1, further comprising repeating (b)-(d) with the second transmit time as the determined first transmit time. ### Claim 12 An apparatus comprising: a transmit media access control module configured to (a) determine a first transmit time for a packet on a transmission medium based on a non-zero number selected from a random number generator; (b) at the determined first transmit time, sense traffic on said transmission medium; (c) if said transmission medium is available, trigger transmission of the packet by a transmitter; and (d) if said transmission medium is not available, defer transmission of the packet to a second transmit time using a second non-zero number selected from the random number generator. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein said second transmit time is further based at least in part on an Inter Packet Gap time. ### Claim 14 (depends on 12) The apparatus of claim 12, further comprising counting a number of instances said transmission of the packet is deferred and deferring said transmission until the number of instances said transmission is deferred reaches a threshold value. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein said transmit media access control module is further configured to terminate attempts to transmit the packet based, at least in part, on the number of instances of said transmission reaching said threshold value. ### Claim 16 (depends on 13) The apparatus of claim 13, wherein said second transmit time is further based at least in part on a back-off process in response to said deferral of transmission. ### Claim 17 (depends on 12) The apparatus of claim 12 wherein said second transmit time is further based at least in part on multiplying the second non-zero number by a programmable access-slot time. ### Claim 18 (depends on 17) The apparatus of claim 17 wherein the programmable access-slot time is determined based on a round trip delay time between any sending and receiving pair of nodes accessing the transmission medium. ### Claim 19 (depends on 17) The apparatus of claim 17, wherein the programmable access-slot time includes a transmit turn-on time. ### Claim 20 (depends on 12) The apparatus of claim 12 wherein a maximum number selectable from the random number generator is determined based on a counter of a number of instances said transmission of the packet is deferred. ### Claim 21 (depends on 16) The apparatus of claim 16 wherein said back-off process is a linear back-off process. ### Claim 22 (depends on 12) The apparatus of claim 12, further comprising repeating (b)-(d) with the second transmit time as the determined first transmit time.