Incremental Decode-and-Forward Protocols for D2D Communication: A Diversity-Multiplexing-Tradeoff Perspective

We propose a slotted incremental decode-and-forward (SIDF) and a non-slotted incremental decode-and-forward (NIDF) protocol for device-to-device communication. Different from previous incremental protocols in literature, a user only spend a portion of its temporal degrees of freedom to help its partner, enabling improved bandwidth efficiency. We derive the diversity-multiplexing tradeoffs (DMTs), and show that NIDF achieves the DMT upper bound whereas SIDF is slightly away from the upper bound at the medium multiplexing gain region. We also show how the DMT optimizing resource allocation factor varies for different multiplexing gains. Numerical outage probability results are shown to line up with the theoretical DMT analysis, and improved bandwidth efficiency over the existing incremental amplify-forward is demonstrated.