1 research outputs found
On the Outage Performance of Non-Orthogonal Multiple Access with One-Bit Feedback
In this paper, the outage performance of downlink non-orthogonal multiple
access (NOMA) is investigated for the case where each user feeds back only one
bit of its channel state information (CSI) to the base station. Conventionally,
opportunistic one-bit feedback has been used in fading broadcast channels to
select only one user for transmission. In contrast, the considered NOMA scheme
adopts superposition coding to serve all users simultaneously in order to
improve user fairness. A closed-form expression for the common outage
probability (COP) is derived, along with the optimal diversity gains under two
types of power constraints. Particularly, it is demonstrated that the diversity
gain under a long-term power constraint is twice as large as that under a
short-term power constraint. Furthermore, we study dynamic power allocation
optimization for minimizing the COP, based on one-bit CSI feedback. This
problem is challenging since the objective function is non-convex; however,
under the short-term power constraint, we demonstrate that the original problem
can be transformed into a set of convex problems. Under the long-term power
constraint, an asymptotically optimal solution is obtained for high
signal-to-noise ratio.Comment: 32 pages, 7 figure