Cooperative versus Non-Cooperative Han-Kobayashi Signaling: Outage Performance

We propose cooperative Han-Kobayashi (H-K) signaling schemes and investigate their performance in comparison with non-cooperative H-K signaling. In the cooperation scenario, the near user relays the base station (BS) common message or the far user's message to increase the received signal-to-interference-plus-noise ratio of the far user. We evaluate the outage performance of the non-cooperative and cooperative signaling schemes. Specifically, we obtain the exact outage probability (OP) of the non-cooperative strategy, and closed-form approximations for the OP of the cooperative schemes. As demonstrated in the comparative results, by setting an appropriate BS's power budget and power allocation, the non-cooperative mechanism has the potential to excel in OP. Finding the best power allocation to achieve the least outage with non-cooperative H-K is not trivial, whereas allocating a small level of the BS's transmit power to the far user's message, and then relaying the said message with a suitable power can yield significant improvements in the outage performance and make the cooperative approach superior.