4 research outputs found
Performance analysis of RF-FSO multi-hop networks
We study the performance of multi-hop networks composed of millimeter wave
(MMW)-based radio frequency (RF) and free-space optical (FSO) links. The
results are obtained in the cases with and without hybrid automatic repeat
request (HARQ). Taking the MMW characteristics of the RF links into account, we
derive closed-form expressions for the network outage probability. We also
evaluate the effect of various parameters such as power amplifiers efficiency,
number of antennas as well as different coherence times of the RF and the FSO
links on the system performance. Finally, we present mappings between the
performance of RF-FSO multi-hop networks and the ones using only the RF- or the
FSO-based communication, in the sense that with appropriate parameter settings
the same outage probability is achieved in these setups. The results show the
efficiency of the RF-FSO setups in different conditions. Moreover, the HARQ can
effectively improve the outage probability/energy efficiency, and compensate
the effect of hardware impairments in RF-FSO networks. For common parameter
settings of the RF-FSO dual-hop networks, outage probability 10^{-4} and code
rate 3 nats-per-channel-use, the implementation of HARQ with a maximum of 2 and
3 retransmissions reduces the required power, compared to the cases with no
HARQ, by 13 and 17 dB, respectively.Comment: Presented at IEEE WCNC 201
On the Performance of Millimeter Wave-based RF-FSO Multi-hop and Mesh Networks
This paper studies the performance of multi-hop and mesh networks composed of
millimeter wave (MMW)-based radio frequency (RF) and free-space optical (FSO)
links. The results are obtained in cases with and without hybrid automatic
repeat request (HARQ). Taking the MMW characteristics of the RF links into
account, we derive closed-form expressions for the networks' outage probability
and ergodic achievable rates. We also evaluate the effect of various parameters
such as power amplifiers efficiency, number of antennas as well as different
coherence times of the RF and the FSO links on the system performance. Finally,
we determine the minimum number of the transmit antennas in the RF link such
that the same rate is supported in the RF- and the FSO-based hops. The results
show the efficiency of the RF-FSO setups in different conditions. Moreover,
HARQ can effectively improve the outage probability/energy efficiency, and
compensate for the effect of hardware impairments in RF-FSO networks. For
common parameter settings of the RF-FSO dual-hop networks, outage probability
of 10^{-4} and code rate of 3 nats-per-channel-use, the implementation of HARQ
with a maximum of 2 and 3 retransmissions reduces the required power, compared
to cases with open-loop communication, by 13 and 17 dB, respectively.Comment: Submitted to IEEE Transactions on Wireless Communication