单载波频域均衡系统中一种简化的IBDFE算法

A Simplification of IBDFE Algorithm in Single Carrier Frequency Domain Equalization System

在单载波频域均衡系统中,线性均衡算法虽然简单易行,但是其抑制噪声干扰和符号间干扰的能力有限,因此需要引入非线性的反馈和迭代机制以进一步提升系统性能.迭代块判决反馈均衡(Iterative Block Decision Feedback Equalization,IBDFE)就是一种行之有效的非线性算法,但其缺点是计算复杂度高.鉴于此,在IBDFE结构的基础上,利用最小均方误差准则,推导出了一种新的简化算法.之后,对简化后算法和现有低复杂度算法的均方误差(Mean Square Error,MSE)性能进行了理论分析和比较,并在两种无线多径衰落信道下对三种不同的算法进行了仿真.结果表明,在所给信道条件下,这种算法在迭代两次后已基本收敛.同时,仿真也验证了MSE分析的结论.最后,对算法复杂度的分析和比较表明,提出的简化算法相比传统IBDFE算法,其误比特率性能有所下降,但能有效地减小计算量.

In single carrier frequency domain equalization （SC-FDE）systems ,linear equalization is simple and practical ,but it does not do well in noise and inter-symbol interference （ISI ）suppression .Therefore ,nonlinear feedback and iteration mechanism is needed to improve the performance .Iterative block decision feedback equalization （IBDFE ）is an effective nonlinear algorithm with a disadvantage of high computational complexity .In view of this ,a simplified algorithm is derived on the basis of IBDFE structure us-ing the minimum mean square error （MMSE ）criterion .Then the mean square error （MSE ）of the simplified algorithm and the existing low complexity algorithm is analyzed and compared .Three algorithms are simulated considering two kinds of wireless multipath fad-ing channels .Results show that the proposed algorithm is convergent after two iterations under the given channels .Simulations also validate the conclusions of MSE analysis .Computational complexity comparison indicates that the proposed algorithm decreases the bit error rate （BER ）performance ,but it can efficiently reduce the amount of calculation .