  In this paper, we deal with the problem of relay selection in mobile edge
computing networks, where a source node transmits a computation-intensive task
to a destination via the aid of multiple relay nodes. It differs from the
traditional relay nodes in the way that each relay node is equipped with an
edge computing server, thus each relay node can execute the received task and
forwards the computed result to the destination. Accordingly, we define a delay
outage probability to evaluate the impact of the relay computing ability on the
link communications, and then propose a latency-best relay selection (LBRS)
scheme that not only consider the communication capability, but also consider
the computing ability. The performance of the proposed relay selection scheme
with the traditional communication-only relay selection (CORS) and
computing-only selection (CPORS) schemes in terms of the delay outage
probability and the diversity order is analyzed, compared with other relay
selection schemes. We show that the proposed LBRS scheme reduces to the
traditional CORS scheme under the high signal-to-noise ratio (SNR) region. We
further reveal that the diversity orders of both the proposed LBRS and CORS
schemes are dependent on the computing ability of relay nodes.
