Patent ID: 8143996
Filing Date: 2012-03-27
Classification: G06K

Abstract:
1. A decentralized RFID system comprising: a first reader for transmitting a first carrier signal; a second reader for transmitting a second carrier signal; a tag for receiving the first and second carrier signals, wherein the tag is responsive to the first carrier signal to transmit a first backscatter signal, and wherein the tag is responsive to the second carrier signal to transmit a second backscatter signal; and wherein the first and second readers further include a first processor and a second processors, respectively, and wherein the first processor measures a degree of interference from the second carrier signal, and wherein the second processor measures a degree of interference from the first carrier signal, the first and second processor each executing instructions to: wherein a selective back-off scheme is employed by each of the first and second readers to ensure that both the first and second readers achieve a respective desired read range, the selective back-off scheme: wherein ρ is the percentage of time a respective first and second reader has attained the required signal-to-noise ratio and τ W is the amount of time a respective first and second readers to wait before return to the respective transmission power levels.