SimCast: Efficient video delivery in MU-MIMO WLANs

Wireless video stream delivery is choppy. This problem becomes much severer in MU-MIMO´s simultaneous video transmission within the same band. Conventional schemes achieve graceful video delivery by harnessing from high data redundancy. However, with concurrent transmission in the same band, the leverage of high data redundancy leads to high probability of collisions and packets loss, which limits the performance. In concurrent video transmission, achieving efficiency over varied link condition is the main issue. To address this issue, this paper presents SimCast (Simultaneous), a cross-layer design for achieving efficient concurrent video uploading/downloading in MU-MIMO WLANs. The key idea of SimCast is to harness frequency diversity of the channel and spatial similarity of users. We implemented SimCast on USRP2 and conducted extensive simulations. Result shows that SimCast achieves higher throughput than traditional schemes by 1.2× on average. Video quality of SimCast outperforms competitive schemes, which is up to 5 dB in PSNR.