0779520-A2 is referenced by 57 patents and cites 13 patents.

In accordance with the present invention, a novel Time Division Multiple Access (TDMA) duplex radio communication system comprises an Interrogator which generates a first radio signal by modulating a first information signal onto a radio carrier signal. The Interrogator transmits the first radio signal to at least one remote Tag of the system. The remote Tag receives and processes the received first radio signal. The remote Tag then modulates a second information signal onto a second radio carrier signal to form a second modulated signal. This second modulated signal is then transmitted, in a time-slotted manner, back to the Interrogator. The remote Tag selects, or is instructed, how many times it should repetitively transmit the second modulated signal; and selects, or is instructed, over how many of the time slots following receipt of the first radio signal the remote Tag should repetitively transmit the second modulated signal. Other embodiments of this invention include the use of Modulated Backscatter to transmit the second modulated signal, and the use of homodyne detection to demodulate the second modulated signal. A Frequency Division Multiple Access (FDMA) duplex radio communication system embodiment utilizes multiple subcarrier frequencies and another embodiment combines the FDMA and the TDMA methods. A Code Division Multiple Access (CDMA) embodiment utilizes multiple spreading codes; in addition, another embodiment combines the CDMA and the TDMA methods.; A novel method for power control of the tag, using modulated backscatter, is also disclosed. Finally, a method for the Interrogator to instruct the Tag to dynamically alter the data rate of the second information signal is also disclosed.

Title
Enhanced uplink modulated backscatter system
Application Number
EP19960308726 19961203
Publication Number
0779520 (A2)
Application Date
December 3, 1996
Publication Date
June 18, 1997
Inventor
Vannucci Giovanni
US
Shober R Anthony
US
Maclellan John Austin
US
Assignee
At & T
US
IPC
G01S 13/82
H04J 03/00
H04B 01/59
G06K 17/00
G01S 13/00
H04J 03/00
H04B 01/59
G06K 17/00
G01S 13/82
G01S 13/78
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