OTFS系统中基于最小多普勒间干扰的导频设计

正交时频空(OTFS)调制系统能够改进时变频选信道的错误概率,但是目前只是简单地采用矩形导频。文中在OTFS系统中一种基于冲激的信道估计模型的基础上,优化其导频图案。在固定导频开销的约束下,最小化多普勒间干扰,也即是最大化被估计的信道平均功率。经论证,该优化问题可以转化为一个经典的背包问题,并可以通过贪心算法求解。仿真结果表明,文中经过优化的导频图案与原矩形导频图案相比,相同的导频开销下,具有更低的均方误差和误码率。

Pilot design based on minimizing inter doppler interference for orthogonal time frequency space modulation

Orthogonal Time-Frequency Space(OTFS) modulation systems can improve the error probability of time-variant frequency selective channels,but only rectangular pilots are used up to now.In this paper,the pilot pattern of an impulse based channel estimation model is optimized in OTFS.Under the constraint of fixed pilot overhead,the inter Doppler interference is minimized,that is to say,the average power of the estimated channel is maximized.It is proved that the optimization problem can be transformed into a classical knapsack problem,and the optimal solution can be obtained by greedy algorithm.The simulation results show that the optimized pilot pattern has lower mean square error and bit error rate under the same pilot overhead compared with the original rectangular pilot pattern.