Method and apparatus for performing rate determination
First Claim
1. In a variable rate communications system, a system for determining, at a receiver, the data rate of a received traffic signal, comprising:
- means for measuring the power of said traffic signal, and for providing a signal indicative of said measured traffic power;
means for measuring the power of a pilot signal, and for providing a signal indicative of said measured pilot power; and
rate determination means for receiving said traffic power signal and said pilot power signal, determining the data rate of said traffic signal in accordance with a ratio of said traffic power signal and said pilot power signal, and providing a selected data rate for said traffic signal.
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Accused Products
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.
115 Citations
31 Claims
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1. In a variable rate communications system, a system for determining, at a receiver, the data rate of a received traffic signal, comprising:
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means for measuring the power of said traffic signal, and for providing a signal indicative of said measured traffic power; means for measuring the power of a pilot signal, and for providing a signal indicative of said measured pilot power; and rate determination means for receiving said traffic power signal and said pilot power signal, determining the data rate of said traffic signal in accordance with a ratio of said traffic power signal and said pilot power signal, and providing a selected data rate for said traffic signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A receiving system for variable rate communications, comprising:
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a receiver for receiving a wide-band signal; a demodulator for demodulating said wide-band signal to produce a traffic signal and a pilot signal, wherein said traffic signal has been transmitted at one of a set of possible transmission rates, and wherein said pilot signal has been transmitted at a constant power and has the same carrier frequency as said traffic signal; power measurement means for measuring the power of said traffic signal and the power of said pilot signal; rate determination means for determining the data rate of said traffic signal in accordance with a ratio of said traffic power signal and said pilot power signal in order to provide a selected data rate for said traffic signal; and decoder means for decoding said traffic signal in accordance with said selected data rate. - View Dependent Claims (13, 14)
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15. A method for determining, at a receiver of a variable rate communications system, the data rate of a received traffic signal, comprising the steps of:
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measuring the power of a traffic signal in order to provide a signal indicative of said measured traffic power; measuring the power of a pilot signal in order to provide a signal indicative of said measured pilot power; and determining the data rate of said traffic signal in accordance with a ratio of said traffic power signal and said pilot power signal to provide a selected data rate. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. In a variable rate communications system, an apparatus for determining, at a receiver, the data rate of a received traffic signal, comprising:
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a pilot power measurer having an input for receiving a pilot signal and an output for providing a signal indicative of the power of said pilot signal; a traffic power measurer having an input for receiving a traffic signal and an output for providing a signal indicative of the power of said traffic signal; and a rate processor having a first input coupled to said pilot power measurer output for receiving said signal indicative of the power of said pilot signal a second input coupled to said traffic power measurer output for receiving said signal indicative of the power of said traffic signal, and an output for providing a rate for said traffic signal, said rate determined based on a ratio of said power of said pilot signal and said power of said traffic signal.
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26. In a variable rate communications system, a system for determining the data rate of received traffic signals, comprising:
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means for measuring the power of each of a plurality of received pilot signals, said received pilot signals transmitted via a plurality of transmission paths from at least one transmitter; means for determining a summed pilot power measurement of the power of said pilot signals; means for measuring the power of each of a plurality of received traffic signals, said received traffic signals transmitted via a plurality of transmission paths from said at least one transmitter; means for determining a summed traffic power measurement of the power of said traffic signals; and means for determining a selected data rate for said traffic signals in accordance with a ratio of said summed pilot power measurement and said summed traffic power measurement. - View Dependent Claims (27, 28, 29, 30, 31)
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Specification