Method and system for determining channel response in a block transmission system
A method and system for determining channel response is provided. The method for determining a channel frequency response (CFR) in a block transmission system comprises performing an N′ point Fast Fourier Transformation (FFT), where N′ is a function of N and K, and N is approximately equal to the number of sub-carriers in a block, and K depends on the coherence bandwidth of the channel corresponding to the block.
1 . A method for determining a channel frequency response (CFR) of a plurality of data symbols in a block transmission system, the method comprising performing an N′ point Fast Fourier Transformation (FFT), wherein N′ is a function of N and K, wherein N is approximately equal to the number of sub-carriers in a block, and K depends on the coherence bandwidth of the channel corresponding to the block.
2 . The method of claim 1 , wherein N′ is approximately equal to a ratio of N and K.
3 . The method of claim 1 , wherein K is an integral power of two.
4 . The method of claim 1 , further comprising estimating a CFR for each Kth sub-carrier index.
5 . The method of claim 4 , further comprising estimating a CFR of each remaining data sub-carrier by interpolating a plurality of estimated CFRs of adjacent Kth sub-carriers, the adjacent Kth sub-carriers being adjacent to the corresponding remaining data sub-carriers, wherein the sub-carrier index of each remaining data sub-carrier is unequal to an integral multiple of K.
6 . The method of claim 5 , wherein K depends on the complexity of the interpolation.
7 . The method of claim 5 , wherein order of interpolation is modified to handle band-edge effects of a block.
8 . A method for determining a channel impulse response (CIR) of a plurality of data symbols in a block transmission system, the method comprising:
a. receiving the plurality of data symbols; and
b. performing an N″ point Inverse Fast Fourier Transformation (IFFT), wherein N″ is a function of N and P, wherein N is approximately equal to the number of sub-carriers in a block, and P is approximately equal to the pilot sub-carrier spacing.
9 . The method of claim 8 , wherein N″ is approximately equal to a ratio of N and Q, wherein Q is a common divisor of N and P.
10 . The method of claim 8 , wherein Q is an integral power of two.
11 . A receiver of a block transmission system, the receiver comprising a channel frequency response (CFR) determining module, the CFR determining module configured to determine a CFR of a plurality of data symbols, wherein the CFR determining module comprises:
a. a Fast Fourier Transformation (FFT) transformer, the FFT transformer configured to perform a N′ point FFT, wherein N′ is a function of N and K, wherein N is approximately equal to the number of sub-carriers in a block, and K depends on the coherence bandwidth the channel corresponding to the block.
12 . The receiver of claim 11 , wherein N′ is approximately equal to a ratio of N and K.
13 . The receiver of claim 11 , wherein K is an integral power of two.
14 . The receiver of claim 11 , wherein a CFR is estimated for each Kth sub-carrier index.
15 . The receiver of claim 11 , wherein the CFR determining module comprises a data dependent CFR estimator coupled to the FFT transformer, the data dependent CFR estimator configured to estimate a CFR of each remaining data sub-carrier by interpolating a plurality of estimated channel frequency responses of adjacent Kth sub-carriers, the adjacent Kth sub-carriers being adjacent to the corresponding remaining data sub-carriers, wherein the sub-carrier index of each remaining data sub-carrier is unequal to an integral multiple of K.
16 . The receiver of claim 15 , wherein K depends on the complexity of the interpolation.
17 . The receiver of claim 15 , wherein the data dependent CFR estimator is configured to modify an order of the interpolation according to band-edge effects of the block.
18 . The receiver of claim 11 , further comprising a channel impulse response (CIR) determining module coupled to the CFR determining module, the CIR determining module configured to determine a CIR, wherein the CIR determining module comprises:
a. an Inverse Fast Fourier Transformation (IFFT) transformer, the IFFT transformer configured to perform a N″ point IFFT, wherein N″ is a function of N and P, wherein P is approximately equal to the pilot sub-carrier spacing.
19 . The receiver of claim 18 , wherein N″ is approximately equal to a ratio of N and Q, wherein Q is a common divisor of N and P.
20 . The receiver of claim 19 , wherein Q is an integral power of two.