Experimental Evaluation of MIMO Capacity for Ultrawideband Body-Centric Wireless Propagation Channels

In this letter, the capacity of ultrawideband (UWB) multiple-input-multiple-output (MIMO) on-body channels is evaluated. Three on-body channels are investigated-namely, Chest-Waist, Wrist-Waist, and Ankle-Waist channels. The data transmission capacities of each channel are evaluated and presented using the two power allocations schemes - namely, equal power allocation and the waterfilling power allocation. Statistical analysis is performed on the MIMO channel data, and the Rician K-factors of the channels are analyzed. It is found that the waterfilling scheme outperforms the equal power scheme in terms of capacity for all three on-body channels, with an average improvement of 1.2 b/s/Hz for signal-to-noise ratio (SNR) less than 12 dB (percentage improvement of 187% at 0 dB and 100% at 8 dB). However, the performances of the two schemes become comparable as the SNR increases with less than 0.28 b/s/Hz difference (percentage improvement of 3.6%) at an SNR level of 20 dB.