Method and apparatus for optimization of wireless communications
First Claim
1. A method of generating and receiving in a wireless transmission system, comprising the steps of:
- a. generating a preamble, said preamble having a first bit rate;
b. generating a data portion, said data portion having a second, higher bit rate;
c. appending the data portion to the preamble to create a signal;
d. modulating a radio frequency with the signal; and
e. enabling a wireless receiver to select a wide bandwidth pre-detection filter and a narrow bandwidth post-detection filter during reception of the preamble and a narrow bandwidth pre-detection filter and a wide bandwidth post-detection filter during reception of the data portion.
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Accused Products
Abstract
A unique wireless transmission signal structure has a preamble at a first data rate and a data portion including the base band signal at a second, higher data rate. The signal is generated in a manner which ensures that the transmitted signal is "on" no more than one half the entire transmission time. A unique wireless transmitter generates the inventive transmission signal. A crystal oscillator drives both a signal generation circuit and a frequency generator. This provides accurate timing and allows the transmission signal to be not self-clocked. A unique wireless transmission receiver has adjustable pre-detection and post-detection filters. When the receiver is scanning for an incoming transmission signal, the pre-detection filter has a wide bandwidth to receive incoming transmission signals within a predictable range of variations due to inaccuracies in the transmitter and receiver. At this time, the post-detection filter has a narrow bandwidth to pass the low bit rate preamble data and reject noise. When a preamble has been detected, the incoming signal is "locked onto" and the pre-detection filter is adjusted to a narrow bandwidth which reject signals other than the incoming signal. The post-detection filter is switched to a wide bandwidth to accept the higher data rate data/CRC portion of the signal. This arrangement allows the transmitter to be relatively inexpensive and to transmit efficiently maintaining short on air time yet the receiver may be selected and sensitive.
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Citations
32 Claims
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1. A method of generating and receiving in a wireless transmission system, comprising the steps of:
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a. generating a preamble, said preamble having a first bit rate; b. generating a data portion, said data portion having a second, higher bit rate; c. appending the data portion to the preamble to create a signal; d. modulating a radio frequency with the signal; and e. enabling a wireless receiver to select a wide bandwidth pre-detection filter and a narrow bandwidth post-detection filter during reception of the preamble and a narrow bandwidth pre-detection filter and a wide bandwidth post-detection filter during reception of the data portion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A wireless transmission system, comprising:
a signal comprising a. a preamble having a first data rate; and b. a digital data portion appended to the preamble, said data portion having a second data rate, the second data rate being higher than the first data rate, the different data rates enabling a wireless receiver to select a wide bandwidth pre-detection filter and a narrow bandwidth post-detection filter during reception of the preamble and a narrow bandwidth pre-detection filter and a wide bandwidth post-detection filter during reception of the data portion, the digital data portion being configured to have no more 1s than 0s regardless of content of the digital data portions. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A wireless signal system, comprising:
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a. a crystal oscillator b. a frequency generator responsive to the crystal oscillator and configured to provide at least one radio frequency to a power amplifier; c. the power amplifier configured to receive the at least one radio frequency from the frequency generator and being configured to receive a digital transmission signal, the amplifier transmitting the radio frequency at times when the digital transmission signal presents a 1 to the amplifier; and d. a signal generation circuit, responsive to the crystal oscillator and configured to receive an input signal and to output the digital transmission signal, said signal generator configured to generate a preamble of the digital transmission signal at a first bit rate and a data portion of the digital transmission signal at a second bit rate, the different data rates enabling a wireless receiver to select a wide bandwidth pre-detection filter and a narrow bandwidth post-detection filter during reception of the preamble and a narrow bandwidth pre-detection filter and a wide bandwidth post-detection filter during reception of the data portion. - View Dependent Claims (19, 20, 21)
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22. A wireless signal receiver, comprising:
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a. an automatic frequency control (AFC) circuit responsive to a processing circuit and configured to generate an AFC signal; b. a bandwidth adjustable pre-detection processor responsive to the AFC signal and configured to receive a wireless signal and configured to have a first bandwidth at times when the receiver is scanning for a signal and to have a second, narrower bandwidth at times when a signal is received and having an output; c. the processing circuit connected to receive the bandwidth adjustable pre-detection processor output; d. a bandwidth adjustable post-detection filter connected to the processing circuit and configured to have a third, narrow bandwidth at times when a preamble of the signal is received and to have a fourth bandwidth wider than the third bandwidth when a data portion of the signal is received; and e. a control device for decoding the signal. - View Dependent Claims (23, 24, 25, 26, 27)
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28. A method of wireless communication, comprising the steps of:
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a. transmitting a wireless signal having a preamble portion comprising a training sequence and a start sequence, the preamble portion having a first data rate, and a data portion having a second data rate, the second data rate being higher than the first data rate; b. receiving the wireless signal, wherein; (i) during reception of the training sequence; (1) receiving the preamble at a receiver; (2) mixing the received preamble to an intermediate frequency; (3) selecting a pre-detection filter, which receives the intermediate frequency, to have a wide bandwidth; and (4) selecting a post-detection filter, which receives the filtered intermediate frequency, to have a narrow bandwidth; (ii) during reception of the starting sequence; (1) selecting the pre-detection filter to have a narrow bandwidth; and (2) selecting the post-detection filter to have a wide bandwidth; and (iii) during reception of the data portion of the signal; (1) receiving the data portion at the receiver; and (2) mixing the received data portion to the intermediate frequency; and (3) decoding the data portion at the control device. - View Dependent Claims (29, 30, 31, 32)
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Specification