SYSTEM AND METHOD FOR PROVIDING BROADCAST TRANSMITTER SPECIFIC PILOTS IN SYNCHRONIZED BROADCAST NETWORKS
A single frequency-based broadcast communication system includes a desired broadcast transmitter and one or more adjacent interfering broadcast transmitters in communication with a receiver over a communication channel is provided. Each of the broadcast transmitters includes a waveform generator for transmitting broadcast transmitter specific pilot signals to the receiver for receiving a superimposed transmitted broadcast transmitter specific pilot signal. The desired broadcast transmitter includes a pilot insertion module and a precoding filter module. The precoding filter module is designed to generate a transmitter specific precoding sequence based on a computed location index for specific pilot signals in a time frequency domain and precode a reference pilot signal to obtain the broadcast transmitter specific pilot signal sequences.
1 . A Single frequency based broadcast communication system comprising:
a desired broadcast transmitter and a plurality of adjacent interfering broadcast transmitters that are in communication with a receiver over a communication channel, wherein the desired broadcast transmitter comprising a waveform generator for transmitting broadcast transmitter specific pilot signals to a receiver, wherein the receiver receives a superimposed signal of the transmitted broadcast transmitter specific pilot signals,
wherein the desired broadcast transmitter is one of the broadcast transmitters from which mobile station intends to receive data and each adjacent interfering broadcast transmitter comprises a pilot insertion module and a precoding filter module and the desired broadcast transmitter comprises a pilot insertion module and a precoding filter module, wherein the precoding filter module is designed to:
generate a transmitter specific precoding sequence from a plurality of precoding sequences based on a computed location index for specific pilot signals in a time frequency domain; and
precode a reference pilot signal to obtain the broadcast transmitter specific pilot signal sequences, based on the plurality of precoded sequences.
2 . The system of claim 1 , wherein precoding of the reference pilot signal comprises obtaining broadcast transmitter specific pilot modulation values that are orthogonal or quasi-orthogonal to the other pre-coded plurality of pilot signals of adjacent broadcast transmitters in a frequency domain.
3 . The system of claim 1 , wherein the receiver on receiving the broadcast transmitter specific pilot signal sequence transmitted from the desired broadcast transmitter and at least one of the plurality of adjacent interfering broadcast transmitters is adapted to:
extract a sub-carrier location value from a computed location index of the broadcast transmitter specific signal sequence;
obtain a plurality of precoding filter coefficients based on the broadcast transmitter specific pilot location value;
compute channel estimates corresponding to the desired broadcast transmitter and the plurality of adjacent interfering broadcast transmitters, based on the extracted sub carrier values and the broadcast transmitter specific pilot sequences; and
compute an individual channel estimate for a plurality of data sub carriers and obtain Channel Frequency Response (CFR) and a Channel Impulse Response (OR) of desired and interfering channels.
4 . The system of claim 3 , wherein the receiver is adapted to estimate the desired broadcast transmitter and the plurality of adjacent interfering broadcast transmitters, wherein the receiver comprises:
a pilot extraction module that is configured to extract the received pilot sequence from the pilot locations obtained for a specific time-frequency domain; where the obtained pilot locations correspond to superimposed pilot values of the desired broadcast transmitter and the plurality of adjacent interfering broadcast transmitters;
a channel estimation module that is configured to estimate a channel frequency response (CFR) of the desired broadcast transmitter and the plurality of adjacent interfering broadcast transmitters, from the extracted pilot sequence; and
a data carrier channel estimation module that is configured to obtain one or more channel estimates corresponding to data subcarriers based on a channel frequency response.
5 . The system of claim 4 , wherein the channel estimation module estimates the channel frequency responses of the desired based station and the plurality of adjacent interfering broadcast transmitters based on a location of a plurality of pre-distorted pilots in a time-frequency domain.
6 . The system of claim 1 , wherein the pilot sequence generation module of the transmitter is further adapted to:
generate broadcast transmitter specific pilot sequences using at least one of one or more sequence generators at different broadcast transmitters and Single Frequency Network (SFN) clusters.
7 . The system of claim 1 , wherein the broadcast transmitter specific pilot sequences comprise one of orthogonal pilot sequences or uncorrelated pilot sequences between the first broadcast transmitter and the second broadcast transmitter, wherein the orthogonal pilot sequences or uncorrelated pilot sequences are generated using sequence generators with different sequence generator polynomials.
8 . The system of claim 1 , wherein the pilot sequence generation module of the transmitter is further adapted to:
generate broadcast transmitter specific pilot sequences using at least one of a pilot reference generator and a broadcast transmitter specific transmitter identity (TxID) sequence, where the broadcast transmitter specific pilot sequences are orthogonal pilot sequences or uncorrelated pilot sequences.
9 . A method performed by a Single frequency based broadcast communication system comprising a desired broadcast transmitter and a plurality of adjacent interfering broadcast transmitters in communication with a receiver over a communication channel, wherein each of the broadcast transmitters comprising a waveform generator for transmitting broadcast transmitter specific pilot signals to the receiver for receiving a superimposed transmitted broadcast transmitter specific pilot signals, characterized in that, a desired broadcast transmitter is one of the broadcast transmitters from which mobile station intends to receive data and each broadcast transmitter comprises a pilot insertion module and a precoding filter module, wherein the method comprises:
generating a transmitter specific precoding sequence from a plurality of precoding sequences based on a computed location index for specific pilot signals in a time frequency domain; and
precoding a reference pilot signal to obtain the broadcast transmitter specific pilot signal sequences, based on the plurality of precoded sequences.
10 . The method of claim 9 , wherein precoding of a plurality of pilot signals comprises obtaining broadcast transmitter specific pilot modulation values that are orthogonal or quasi-orthogonal to the other pre-coded plurality of pilot signals of adjacent broadcast transmitters in a frequency domain.
11 . The method of claim 9 , wherein the method comprises extracting, by the receiver, a sub-carrier location value from a computed location index of the broadcast transmitter specific signal sequence;
obtaining, by the receiver, a plurality of precoding filter coefficients based on the broadcast transmitter specific pilot location value;
computing, by the receiver, Channel estimates corresponding to the desired broadcast transmitter and the plurality of adjacent interfering broadcast transmitters, based on the extracted sub carrier values and the broadcast transmitter specific pilot sequences; and
performing, by the receiver, a channel estimation of a desired channel and one or more interfering channels by computing an individual channel estimate for a plurality of data sub carriers.
12 . The method of claim 11 , wherein performing the channel estimation of the one or more interfering channels comprises:
extracting, by a pilot extraction module of the receiver, the received superimposed pilot sequence values from a plurality of pilot locations obtained for a specific time-frequency domain; where the pilot locations correspond to received superimposed pilot values of a desired broadcast transmitter and an interfering channel;
estimating, by a channel estimation module of the receiver, channel frequency response (CFR) of the desired broadcast transmitter and the interfering channels at the extracted pilot location; and
obtaining, by a data carrier channel estimation module ( 320 ) of the receiver, one or more channel estimates corresponding to data subcarriers based on a channel frequency.
13 . The method of claim 9 , wherein the method comprises generating, by the pilot sequence generation module, the broadcast transmitter specific pilot sequences using at least one of one or more sequence generators at different broadcast transmitters and Single Frequency Network (SFN) clusters.
14 . The method of claim 13 , wherein the broadcast transmitter specific pilot sequences comprise one of orthogonal pilot sequences or uncorrelated sequences between a first adjacent interfering broadcast transmitter and a second adjacent interfering broadcast transmitter, wherein the orthogonal pilot sequences or uncorrelated pilot sequences are generated using sequence generators with different sequence generator polynomials.
15 . The method of claim 9 , wherein the method comprises
generating, by the pilot sequence generation module, the broadcast transmitter specific pilot sequences using at least one of a pilot reference generator and a broadcast transmitter specific transmitter identity (TxID) sequence, where the broadcast transmitter specific pilot sequences are orthogonal pilot sequences or uncorrelated pilot sequences.