Joint channel estimation and data detection method for STBC/OFDM systems

A joint channel estimation and data detection method for STBC/OFDM systems, comprising the following steps:

• a preliminary step, in which, after passing the received signals through an OFDM demodulator, frequency-domain signals R1[k] and R2[k] of the complementary-coded pilot preambles in two successive OFDM symbol times, as well as two successive OFDM data symbols R1(i)[k] and R2(i)[k] at the ith time slot, are obtained;
• an initial step for setting up the predetermined number Np of the channel paths, using a complementary-coded pilot preambles to estimate the channel impulse response, then using this estimation result of the channel impulse response to calculate a path selective set Sm. and furthermore, in accordance with the path selective set Sm, determining the number Lm of the selected paths and the excess delay τm,l of the selected path, and then calculating the initial channel state information vector y(1,0) and the Hessian matrix F;
• a tracking step, in which the initial value v of the recursion index is set to 1 at first, and the maximum number of recursion is set to V;
• if the index v of recursion is 1, use sparse pilot subcarriers to calculate channel state information Ĥm[k], and calculate a searching direction vector Ψ that is obtained by using the sparse pilot subcarriers, and then calculate a searching direction vector
• g(i,1)=μγΨ(i)+(1−μ)(F+λI2(L1+L2))−1∇f(y(i,0))
• if the index of recursion is not equal to 1, calculate the searching direction vector as g(i,v)=(F+λI2(L1+L2))−1∇f(y(i,v−1));
• next, update the channel state information vector by y(i,v)=y(i,v−1)−g(i,v), and increase the index of recursion by 1;
• if the index v of recursion is less than or equal to V, repeat the searching of the direction vector;
• finally, take the channel state information estimated at this time slot to be the initial value of the channel state information at the next time slot, i.e. y(i+1,0)=y(i,V).

A joint channel estimation and data detection method for OFDM systems, comprising the following steps:

• a preliminary step, in which, after passing the received signals through an OFDM demodulator, a frequency-domain signal R[k] of the pilot preamble at an OFDM symbol time, as well as an OFDM data symbol R(i)[k] at the ith time slot, are obtained;
• an initial step for setting up the predetermined number Np of the channel paths, using a pilot preamble to estimate the channel impulse response, then using this estimation result of the channel impulse response to calculate a path selective set S, and furthermore, in accordance with the path selective set S, determining the number L of the selected paths and the excess delay τl of the selected path, and then calculating the initial channel state information vector y(1,0) and the Hessian matrix F;
• A tracking step, in which the initial value v of the recursion index is set to 1 at first, and the maximum number of recursion is set to V;
• then calculate the searching direction vector and update the channel state information vector by y(i,v)=y(i,v−1)−g(i,v) as well as increase the index of recursion by 1;
• if the index v of recursion is less than or equal to V, repeat the searching of the direction vector and update the channel state information vector;
• finally, take the channel state information estimated at this time slot to be the initial value of the channel state information at the next time slot, i.e. y(i+1,0)=y(i,V).

A joint channel estimation and data detection method for OFDM systems, comprising the following steps:

• a preliminary step, in which, after passing the received signals through an OFDM demodulator, a frequency-domain signal R[k] of the pilot preamble at an OFDM symbol time, as well as an OFDM data symbol R(i)[k] at the ith time slot, are obtained;
• an initial step for setting up the predetermined number Np of the channel paths, using a pilot preamble to estimate the channel impulse response, then using this estimation result of the channel impulse response to calculate a path selective set S, and furthermore, in accordance with the path selective set S, determining the number L of the selected paths and the excess delay τl of the selected path, and then calculating the initial channel state information vector y(1,0) and the Hessian matrix F;
• A tracking step, in which the initial value v of the recursion index is set to 1 at first, and the maximum number of recursion is set to V;
• if the index v of recursion is 1, use sparse pilot subcarrier to calculate channel state information Ĥ[k], and calculate a searching direction vector Ψ that is obtained by using the sparse pilot subcarriers, and then calculate a searching direction vector
• g(i,1)=μγΨ(i)+(1−μ)(F+λI2L)−1∇f(y(i,0))
• if the index of recursion is not equal to 1, calculate the searching direction vector as g(i,v)=(F+λI2L)−1∇f(y(i,v−1));
• next, update the channel state information vector by y(i,v)=y(i,v−1)−g(i,v) and increase the index of recursion by 1;
• if the index v of recursion is less than or equal to V, repeat the searching of the direction vector;
• finally, take the channel state information estimated at this time slot to be the initial value of the channel state information at the next time slot, i.e. y(i+1,0)=y(i,v).