Operating Region Boundary for Coordinated Two-Point Joint Diversity Transmission Under an Outage Rate Requirement

In this letter, we check the feasibility of coordinated two-point (Co2P) joint diversity transmission (JDT) under an outage rate requirement. We first derive the outage rate expression for a Co2P JDT network in Rayleigh fading channels. We then obtain the relationship for determining the exact operating region boundary. Furthermore, we present an approximate operating region boundary using a simple piecewise linear approximation and another approximate operating region boundary using a more accurate quartic approximation. Finally, we analyze the resulting outage rates. From numerical results, we validate that the outage rate curve, along with the approximate boundary using the quartic approximation, matches well with the required outage rate over the entire signal-to-noise ratio (SNR) regime. In addition, we validate that the approximate boundary can guarantee the required outage rate by introducing small margins of +0.2 dB for both the boundary-forming mean branch SNRs.