  This work focuses on the half-duplex (HD) relaying based on the generalized
quantize-and-forward (GQF) scheme in the slow fading Multiple Access Relay
Channel (MARC) where the relay has no channel state information (CSI) of the
relay-to-destination link. Relay listens to the channel in the first slot of
the transmission block and cooperatively transmits to the destination in the
second slot. In order to investigate the performance of the GQF, the following
steps have been taken: 1)The GQF scheme is applied to establish the achievable
rate regions of the discrete memoryless half-duplex MARC and the corresponding
additive white Gaussian noise channel. This scheme is developed based on the
generalization of the Quantize-and-Forward (QF) scheme and single block with
two slots coding structure. 2) as the general performance measure of the slow
fading channel, the common outage probability and the expected sum rate (total
throughput) of the GQF scheme have been characterized. The numerical examples
show that when the relay has no access to the CSI of the relay-destination
link, the GQF scheme outperforms other relaying schemes, e.g., classic
compress-and-forward (CF), decode-and-forward (DF) and amplify-and-forward
(AF). 3) for a MAC channel with heterogeneous user channels and
quality-of-service (QoS) requirements, individual outage probability and total
throughput of the GQF scheme are also obtained and shown to outperform the
classic CF scheme.
