A Novel Simulator of Nonstationary Random MIMO Channels in Rayleigh Fading Scenarios

Abstract

For simulations of nonstationary multiple-input multiple-output (MIMO) Rayleigh fading channels in time-variant scattering environments, a novel channel simulator is proposed based on the superposition of chirp signals. This new method has the advantages of low complexity and implementation simplicity as the sum of sinusoids (SOS) method. In order to reproduce realistic time varying statistics for dynamic channels, an efficient parameter computation method is also proposed for updating the frequency parameters of employed chirp signals. Simulation results indicate that the proposed simulator is effective in generating nonstationary MIMO channels with close approximation of the time-variant statistical characteristics in accordance with the expected theoretical counterparts.

A Novel Simulation Model for Nonstationary Rice Fading Channels

“…In order to apply the classic SoC method, some modified simulators [9-11, 13, 14] directly use 2 ( ) and 2 ( ) to substitute 2 and 2 in (7), respectively. However, it can be proved that the output phases of these models are not accurate and the output Doppler frequencies do not agree with the theoretical ones [18]. In this Wireless Communications and Mobile Computing 3 paper, we use 2 ∫ 0 ( )d and 2 ∫ 0 ( )d to replace 2 ( ) and 2 ( ) , respectively, and the new simulator can be written as…”

“…There are a number of research papers on designing accurate and efficient simulators [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. For the good fitting with plan-wave propagation channels, the sum-of-sinusoids (SoS) [1,2] or sum-ofcisoids (SoC) [3] based simulators and their derivatives [4][5][6][7][8] have gained the most widespread acceptance.…”

“…However, measurement campaigns have proved that the WSS assumption is only valid for a short time interval [20]. Therefore, several modified SoC-based simulators were proposed in [9][10][11][12][13][14][15][16][17][18][19] to generate nonstationary fading channels. For example, the WINNER+ model [9] was simulated by generating several independent channel segments with different simulation parameters.…”

“…To overcome this shortcoming, a new method, namely, sum of frequency modulation signals [12,[15][16][17][18] or sum of chirp signals [19], was proposed to simulate nonstationary Rayleigh channels very recently, but it lacked implementation details and performance analyses. To fill this gap, this paper develops a new simulator based on this idea to generate the nonstationary Rice fading channels under nonisotropic scattering scenarios, as well as the upgraded computation methods of simulation parameters.…”

A Flexible FPGA-Based Channel Emulator for Non-Stationary MIMO Fading Channels

“…To the best of our knowledge, the aforementioned channel emulators still adopted traditional stationary channel models and considered the non-stationary aspect by updating parameters periodically. However, we have found that the output fading phases of this kind of method are not accurate, which leads to the output Doppler power spectrum density (DPSD) not fitting well with the theoretical ones [28]. To overcome this shortcoming, an improved 3D non-stationary geometry-based stochastic model (GBSM) was proposed in [27] and implemented in a 2 × 2 MIMO channel emulator.…”