Transmitting Bluetooth signals using WiFi hardware
View Patent ↗A technique is presented that enables transmitting data packets decodable in accordance with a first wireless communication protocol using a transmitter configured in accordance with a second wireless communication protocol. In an example implementation of this disclosure, Bluetooth decodable packets can be sent with existing and widely-deployed WiFi devices without modifying NIC firmware or hardware. The transmitted packets are decodable by unmodified Bluetooth devices, thus eliminating the cost of dedicated Bluetooth hardware and deployment.
1 . A computer-implemented method for transmitting data packets decodable in accordance with a first wireless communication protocol using a transmitter configured in accordance with a second wireless communication protocol, comprising:
receiving, by a computer processor, an in-phase and quadrature (IQ) signal to be sent by the transmitter, where the IQ signal includes one or more symbols therein and is to be decoded in accordance with the first wireless communication protocol;
for each of the one or more symbols, manipulating a given symbol to compensate for cyclic prefix insertion, converting the manipulated symbol from time domain to frequency domain, and selecting a constellation from a constellation diagram for the converted symbol, where the selected constellation has shortest Euclidean distance to the converted symbol and corresponds to a bit sequence; and
for each bit sequence, reconstructing, by the computer processor, an input bit sequence for an encoder, thereby constructing a target bit stream for the transmitter.
2 . The method of claim 1 further comprises transmitting the target bit stream using the transmitter.
3 . The method of claim 1 wherein manipulating the given symbol to compensate for cyclic prefix insertion comprises replacing the last n samples in the cyclic prefix with the last n samples in the given symbol, concatenating the first 8−n samples in the cyclic prefix and the last n samples in the given symbol to form a replacement string, and replacing the last 8 samples in the symbol with the replacement string, where n is an integer between zero and eight.
4 . The method of claim 2 wherein manipulating the given symbol to compensate for cyclic prefix insertion comprises replacing a first sample after the cyclic prefix of the given symbol, with a first sample in a next cyclic prefix.
5 . The method of claim 1 further comprises manipulating the given symbol to compensate for cyclic prefix insertion in accordance with
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Where Θ is phase, N is number of samples in the given symbol and n is a sample in the given symbol.
6 . The method of claim 1 further comprises transmitting the target bit stream using shortest cyclic prefix.
7 . The method of claim 1 wherein converting the manipulated symbol from time domain to frequency domain comprises using Discrete Fourier Transform.
8 . The method of claim 1 wherein the input bit sequence is reconstructed using a Viterbi algorithm.
9 . The method of claim 1 wherein the input bit sequence is reconstructed using lookup tables.
10 . The method of claim 1 further comprises selecting a frequency in the second wireless communication protocol such that pilot subcarriers and null subcarriers in the second wireless communication protocols have minimal frequency overlap with a desired transmitting channel of the first wireless protocol.
11 . The method of claim 1 further comprises aligning transmission of each data packet prepared in accordance with the second wireless communication protocol with time slots of the first wireless communication protocol.
12 . The method of claim 1 further comprises modulating the IQ signal within one channel of the second communication protocol to compensate for frequency difference between the second communication protocol and the first communication protocol, where the step of modulating the IQ signal occurs before the step of manipulating the given symbol to compensate for cyclic prefix insertion.
13 . A computer-implemented method for transmitting data packets decodable in accordance with a first wireless communication protocol using a transmitter configured in accordance with a second wireless communication protocol, comprising:
receiving, by a computer processor, an in-phase and quadrature (IQ) signal to be sent by the transmitter, where the IQ signal includes one or more symbols therein and is to be decoded in accordance with the first wireless communication protocol;
for each of the one or more symbols, manipulating a given symbol to compensate for cyclic prefix insertion, converting the manipulated symbol from time domain to frequency domain, and selecting a constellation from a constellation diagram for the converted symbol, where the selected constellation has shortest Euclidean distance to the converted symbol and corresponds to a bit sequence; wherein the given symbol is manipulated to compensate for cyclic prefix insertion by replacing the last n samples in the cyclic prefix with the last n samples in the given symbol, replacing a first sample after the cyclic prefix of the given symbol with a first sample in a next cyclic prefix, concatenating the first 8−n samples in the cyclic prefix with the last n samples in the given symbol to form a replacement string, and replacing the last 8 samples in the symbol with the replacement string, where n is an integer between zero and eight;
for each bit sequence, reconstructing, by the computer processor, an input bit sequence for an encoder, thereby constructing a target bit stream for the transmitter; and
transmitting the target bit stream using the transmitter.
14 . The method of claim 13 further comprises transmitting the target bit stream using shortest cyclic prefix.
15 . The method of claim 13 wherein converting the manipulated symbol from time domain to frequency domain comprises using Discrete Fourier Transform.
16 . The method of claim 13 further comprises selecting a frequency in the second wireless communication protocol that avoids pilot subcarriers and null subcarriers in the second wireless communication protocols.
17 . The method of claim 13 further comprises aligning transmission of each data packet prepared in accordance with the second wireless communication protocol with time slots of the first wireless communication protocol.
18 . The method of claim 13 further comprises modulating the IQ signal within one channel of the second communication protocol to compensate for frequency difference between the second communication protocol and the first communication protocol, where the step of modulating the IQ signal occurs before the step of manipulating the given symbol to compensate for cyclic prefix insertion.
19 . A computer-implemented method for transmitting data packets containing audio data and decodable in accordance with a first wireless communication protocol using a transmitter configured in accordance with a second wireless communication protocol, comprising:
receiving, by a computer processor, an in-phase and quadrature (IQ) signal to be sent by the transmitter, where the IQ signal includes one or more symbols therein and is to be decoded in accordance with the first wireless communication protocol;
modulating the IQ signal within one channel of the second communication protocol to compensate for frequency difference between the second communication protocol and the first communication protocol;
for each of the one or more symbols, manipulating a given symbol to compensate for cyclic prefix insertion, converting the manipulated symbol from time domain to frequency domain, and selecting a constellation from a constellation diagram for the converted symbol, where the selected constellation has shortest Euclidean distance to the converted symbol and corresponds to a bit sequence; and
for each bit sequence, reconstructing, by the computer processor, an input bit sequence for an encoder, thereby constructing a target bit stream for the transmitter.
20 . The method of claim 19 wherein modulating the IQ signal within one channel of the second communication protocol comprises introducing a frequency offset to the IQ signal.
21 . The method of claim 19 wherein modulating the IQ signal within one channel of the second communication protocol further comprises frequency hopping the IQ signal amongst subcarrier frequencies within the one channel of the second communication protocol.