Multiplex communications – Communication over free space – Combining or distributing information via code word channels...
Patent
1996-10-30
1999-02-16
Pham, Chi H.
Multiplex communications
Communication over free space
Combining or distributing information via code word channels...
370468, 455 671, H04B 7216, H04J 322
Patent
active
058727752
ABSTRACT:
A system and method for determining the transmission rate of a data signal at a receiver of a variable rate communications system. A vocoder at a transmitter encodes a frame of data into symbols according to one of a set of discrete data rates. When the data rate is lower than the maximum, each symbol is repeated a number of times as required to achieve a constant number of symbols in each frame. The data signal is transmitted at a power proportional to the data rate of the frame. A reference signal is also transmitted. The reference signal is transmitted at a constant power. Further, the data signal has the same carrier frequency as a reference signal so that they exhibit the same fading characteristics as they are transmitted through the channel. At a receiver, the power of the data signal and the power of reference signal are measured as received. The ratio of the power of the data signal to the power of the reference signal is compared with a predetermined ratio of the power of a maximum rate data signal to the power of the reference signal. The result of the comparison will indicate the encoded data rate of the received frame of data. The rate determined by the rate determination system is then used to properly decode the frame of data. A vocoder at the receiver further processes the data for interface with the user.
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Saints Keith W.
Tiedemann Jr. Edward G.
Golden Linli
Greenhaus Bruce W.
Miller Russell B.
Ngo Ricky Q.
Pham Chi H.
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