Applique Tools With the envisioned massive connectivity era, one of the challenges for 5G/Beyond 5G (B5G) wireless systems will be handling the unprecedented spectrum crunch.A potential solution has emerged in the form of spectrum sharing, which deviates from a monopolistic spectrum usage system.This paper investigates the medium access control (MAC) as a means of increasing the viability of the spectrum sharing technique.We first quantify the opportunity of spectrum access in a probabilistic manner, a method referred to as opportunistic (OP) map.Based on the OP framework, we propose a random MAC algorithm in which the access of a node is randomly determined with its own OP value.
As a possible application of our OP-map based random MAC, we propose a flexible half-duplex (HD)/full-duplex (FD) communication where each pair decides the Transfer Equipment - Benches duplexing mode according to the OP values of the two pair nodes.This approach fits well with the spectrum sharing system since it enables a flexible operation for the spectrum access according to the spectrum usage level.From the numerical analysis, we validate the feasibility and verify the performance enhancements by implementing a field-programmable gate array (FPGA) based real-time prototype.We further carry out extensive 3D ray-tracing based system-level simulations on investigating the network-level performance of the proposed system.Measurements and numerical results confirm that the proposed architecture can achieve higher system throughput than conventional LTE-TDD (time division duplex) systems.