Joint-over-Transmissions Project and Forward Relaying for Single Carrier Broadband MIMO ARQ Systems

Abstract

In this contribution, we present a new class of project-andforward (PF) relays operating with broadband MIMO hybrid ARQ-aided cooperative systems. Their architecture enables to jointly perform the orthogonal projection over multiple ARQ transmissions, increasing thereby the relay diversity order and achieving an interesting power gain over amplify-and-forward (AF)-based relaying schemes.

Security Enhancement of Cooperative Single Carrier Systems

“…Substituting (E.6) and (E.4) into (E.2), we derive the asymptotic expression for the ergodic secrecy capacity as (26).…”

“…Corollary 3: The asymptotic ergodic secrecy rate atα 1 → ∞ and a fixedα 2 is given by (26) at the top of the next page. In (26), ψ (·) is the digamma function [37].…”

“…Asα 1 increases, the multiplexing gain S ∞ approaches 1/2. Since a larger diversity has a more influence from the second term in the right hand side of (26), the convergence speed to 1/2 becomes slower as the diversity gain increases.…”

“…• Cooperative relaying systems: For several relaying protocols such as DF and AF, as well as project and forward relaying [26], optimal power allocation [27], new receiver design [28], optimal training sequences for channel estimation [29], and best terminal selection [30] were proposed to enhance the performance.…”