Dynamic Spectrum Access In Wireless Networks

Due to the explosive growth of mobile broadband service and machine communi-cation,wireless traffic will experience explosive growth in 5G era.Dynamic spectrum access（DSA）is envisioned as an efficient mechanism to address the tradeoff between spectrum shortage and rapidly increasing user demand efficiently.This paper study multi-scale hierarchical resource allocation and distributed dynamic spectrum access,and propose novel algorithms to solve these problems.We execute simulation with different complex wireless environment to verify efficiency and robustness of our pro-posed algorithms.The contribution of this paper is as follows:1.We study resource allocation problem in virtual wireless network.We slice wireless spectrum and power resource,to satisfy diverse transmission requirement of users,and propose multi-scale structure to pre-assign inter-slice subchannels and schedule intra-slice subchannel and power resource,in order to reduce the complex of wireless resource allocation and increase the independence of different slices.2.In the inter-slice resource allocation and the intra-slice dynamic spectrum ac-cess problem,we aim to minimize length of data packets for transmission.To guarantee network stability and balance the tradeoff between network stability and system perfor-mance,we introduce Lyapunov drift-plus-penalty function to simplify the optimization problem.To solve the optimization problem,we propose a two-step method,includ-ing heuristic subchannel allocation and fast barrier algorithm for resource allocation.Simulation results show that our proposed algorithms can improve system throughput efficiently.3.We study absolutely distributed dynamic spectrum access problem,without coordination and information exchange among users,and no prior knowledge is avail-able.Then,we formulate and solve the problem based on multi-armed bandits（MAB）problem,to realize wireless communication learning and coordination in absolute dis-tributed dynamic spectrum access.4.We consider complex dynamic spectrum access problem,where distribution of channel availability is varying over time.In addition,due to the variation of wire-less access requirement,number of active users is changing.To solve the problem of unstable channel distribution,we proposeγ-Thompson sampling algorithm to keep trace with changing channel model.To solve the problem of changing active users,we proposeρ^prandpolicy for user coordination.Simulation results show that our pro-posed algorithm can achieve logarithmic regret function over time in complex wireless environment,and performs much better than other algorithms.In conclusion,we study dynamic spectrum access in wireless network,and pro-pose algorithm to solve relative problems,achieve more efficient and flexible resource allocation.Simulation results show our proposed algorithms improve utilization of wireless resource with better flexibility and robustness.The research work of this pa-per provides a feasible way to optimize the design of wireless network in spectrum access in the future.