Realtime streaming with guaranteed QoS over wireless D2D networks

We consider a group of co-located wireless peer devices that desire to synchronously receive a live content stream. The devices are each equipped with an expensive unicast base-station-to-device (B2D) interface, as well as a broadcast device-to-device (D2D) interface over a shared medium. The stream is divided into blocks, which must be played out soon after their initial creation. If a block is not received within a specific time after its creation, it is rendered useless and dropped. The blocks in turn are divided into random linear coded chunks to facilitate sharing across the devices. We transform the problem into the two questions of (i) deciding which peer should broadcast a chunk on the D2D channel at each time, and (ii) how long B2D transmissions should take place for each block. We analytically develop a provably-minimum-cost algorithm that can ensure that QoS targets can be met for each device. We study its performance via simulations, and present an overview of our implementation on Android phones using the algorithm as a basis.