Performance Analysis of Multiuser FSO/RF Network Under Non-Equal Priority With $P$ -Persistence Protocol

Abstract

This paper presents and analyzes a novel multiuser network based on hybrid free-space optical (FSO)/radiofrequency (RF) transmission system, where every user is serviced by a primary FSO link. When more than one FSO link fail, the central node services these corresponding users by using a common backup RF link according to a non-equal priority with p persistence servicing protocol. A novel discrete-time Markov chain model is developed for the proposed network, where different transmission rates over both RF and FSO links are assumed. We investigate the throughput from central node to the user, the average size of the transmit buffer allocated for every user, the frame queuing delay in the transmit buffer, the efficiency of the queuing system, the frame loss probability, and the RF link utilization. The network's users are arranged in an ascending order. As the order of the failed user increases, the corresponding performance criteria gets worse due to the non-equal priority servicing protocol. Numerical examples show that transmitting a data frame with probability p when using the common backup RF link, achieves considerable performance improvement that approaches the performance of the multiuser FSO/RF network when using equal priority protocol to serve all the remote users.

Retrofitting FSO Systems in Existing RF Infrastructure: A Non-Zero-Sum Game Technology

“…Time hysteresis (TH) and power hysteresis (PH) modifications to the hard-switching approach were studied in [46], where the switching threshold may be variable based on the channel conditions and history. A multi-user FSO/RF hybrid network scheme was proposed in [47], where a primary FSO link services every user. When the FSO link fails, a central node allocates a backup RF link with non-equal priority to different users.…”

Roadmap on optical communications

“…A more practical soft-switching using a dual-FSO threshold can be adopted to reduce the loss of information packets associated with frequent back-and-forth switching between FSO and RF links [334]. In addition, to avoid having a dedicated RF link for each FSO feeder link, a shared backup RF link can be employed by multiple optical users in case a FSO feeder links fails [335]. Site diversity among multiple OGGSs is another effective approach to avoid outages due to fog or cloud obstruction [336].…”

Retrofitting FSO Systems in Existing RF Infrastructure: A Non-Zero Sum Game Technology

“…Time Hysteresis (TH) and Power Hysteresis (PH) modifications to the hard-switching approach were studied in [45], where the switching threshold may be variable based on the channel conditions and history. A multi-user FSO/RF hybrid network scheme was proposed in [46], where a primary FSO link services every user. When the FSO link fails, a central node allocates a backup RF link with non-equal priority to different users.…”