Abstract
A rapid change of channels in high-speed mobile communications will lead to difficulties in channel estimation and tracking but can also provide Doppler diversity. In this paper, the performance of a multiple-input multiple-output system with pilot-assisted repetition coding and spatial multiplexing is studied. With minimum mean square error (MMSE) channel estimation, an equivalent channel model and the corresponding system model are presented. Based on random matrix theory, asymptotic expressions of the normalized achievable sum rate of the linear receivers, such as the maximal ratio combining (MRC) receiver, MMSE receiver and MRC-like receiver, are derived. In addition, according to the symbol error rate of the MRC-like receiver, the maximum normalized Doppler diversity order and the minimum coding gain loss can be achieved when the repetition number and signal-to-noise ratio tend to infinity, and the corresponding conditions are derived. Based on the theoretical results, the impacts of different system configurations and channel parameters on the system performance are demonstrated.
Highlights
With the popularization of high-speed data services, the demand for high-performance wireless communication on high-speed trains (HSTs) is increasing
We investigate the performance of high-mobility Multiple-input multipleoutput (MIMO) communications with Doppler diversity under imperfect channel state information (CSI)
CAPACITY ANALYSIS OF maximal ratio combining (MRC), minimum mean square error (MMSE) AND MRC-LIKE RECEIVERS we study the spectral efficiency of the system represented in formula (10) with different receivers
Summary
With the popularization of high-speed data services, the demand for high-performance wireless communication on high-speed trains (HSTs) is increasing. In a high-mobility scenario, considering the fast change of the channel and adding redundancy across different time slots, such as with repetition coding, Doppler diversity can be exploited; the system performance can be improved. In [15], the combination of a massive MIMO system and general orthogonal precoding was proposed to utilize full diversity in doubly selective channels Other coding methods, such as the Alamouti code, can be combined with repetition code to get more performance gains. The application of Doppler diversity technology in an MIMO system could improve the throughput and reliability of high-mobility wireless communications. We investigate the performance of high-mobility MIMO communications with Doppler diversity under imperfect CSI. According to proposition 2 in [16], as long as the pilot interval satisfies (NT + K ) T ≤ 0.5/fD , an accurate channel estimation can be obtained
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