  We propose a time-division uplink transmission scheme that is applicable to
future cellular systems by introducing hybrid device-to-device (D2D) and
infrastructure cooperation. We analyze its spectral efficiency and outage
performance and show that compared to existing frequency-division schemes, the
proposed scheme achieves the same or better spectral efficiency and outage
performance while having simpler signaling and shorter decoding delay. Using
time-division, the proposed scheme divides each transmission frame into three
phases with variable durations. The two user equipments (UEs) partially
exchange their information in the first two phases, then cooperatively transmit
to the base station (BS) in the third phase. We further formulate its common
and individual outage probabilities, taking into account outages at both UEs
and the BS. We analyze this outage performance in Rayleigh fading environment
assuming full channel state information (CSI) at the receivers and limited CSI
at the transmitters. Results show that comparing to non-cooperative
transmission, the proposed cooperation always improves the instantaneous
achievable rate region even under half-duplex transmission. Moreover, as the
received signal-to-noise ratio increases, this uplink cooperation significantly
reduces overall outage probabilities and achieves the full diversity order in
spite of additional outages at the UEs. These characteristics of the proposed
uplink cooperation make it appealing for deployment in future cellular
networks.
