Abstract:
In an interference-limited 5G Narrowband internet of
things (NB-IoT) heterogeneous networks (HetNets), device-to-
device (D2D) relaying technology can provide coverage expansion
and increase network throughput for cell-edge NB-IoT users
(NUE). However, as D2D relaying improves the network's spectral
efficiency, it makes interference management and resource
allocation more difficult. To improve cell-edge user quality of
service (QoS), we propose an interference-aware and coverage
analysis scheme for 5G NB-IoT D2D relaying. We divide the
optimization problem into three sub-problems to reduce algorithm
complexity. First, we use the max-max signal-to-noise plus
interference ratio (Max-SINR) to select an optimal D2D relay with
the highest channel-to-interference plus noise ratio (CINR) to
relay the source NUE information to the NB-IoT base station
(NBS). Second, we optimize the transmit power (TP) of the cell-
edge NUE to the relay under the peak interference power
constraints using a Lagrange dual approach to ensure the user's
service life. We fixed the TP between the D2D relay and the NBS
and then transformed the D2D relay's coverage problem that
maximizes the network uplink data rate into a 0-1 integer
programming problem. Then, we propose a heuristic algorithm to
obtain the system performance. Due to the high channel gain
between the two communicating devices, the simulation results
show that the Max-SINR selection scheme outperforms the other
relay selection schemes except for the D2D communication scheme
in efficiency, data rate and SINR.
