Research On Interference Coordination Algorithms In 5G Dense Network

In the research on 5G mobile communications,dense deployment of low-power nodes(LPNs)is a key technology for the enhancement of the network capacity.Due to the stochasticity and high density of the node deployment,and that the coverage regions with various sizes can be overlapped,more complex interference issues need to be handled in 5G network.Since 5G network is supposed to be user-centric,it is necessary to consider users' service requirements.Regarding the system stabilily and delay as the key performance related to users' experience,this paper investigates the downlink interference coordination schemes in the senarios with hotzones,and the interference coordination in the 5G self-backhaul network.Almost blank subframe(ABS)based enhanced Inter-cell Interference Coordination(eICIC)is a key solution for inter-tier interference in heterogeneous network(HetNet).To reduce the interference while maintaining the system stability,this paper proposes a Lyapunov-based dynamic enhanced inter-cell interference coordination(eICIC)algorithm.Firstly,suppose that the system state can be expressed as the vector of the queue states of the macro eNodeBs(MeNBs)and pico eNodeBs(PeNBs).Leveraging the Lyapunov optimization technique,the problem is formulated to minimize the system congestion.To maintain the queue stability of both MeNBs and PeNBs,a dynamic ABS configuration and resource allocation algorithm(DACRAA)is proposed.In DACRAA,the subframe configuration and resources allocation are jointly determined based on the current queue state information and channel state information.Furthermore,considering the complexity and the signaling overhead in DACRAA,a semi-static ABS configuration with an interference impact factor(IIF)based scheduling(SACIS)is proposed.In SACIS,DACRAA is called to optimize the ABS ratio,only when the queue length of any MeNB or PeNB exceed a predefined threshold.The simulation results show that DACRAA can guarantee the queue stability of both MeNBs and PeNBs,and the system congestion is reduced comparing to the conventional algorithm.Besides,SACIS can reduce the complexity and signaling overhead comparing to DACRAA,while resulting relatively low congestion.The anticipated massive deployment of the small cells entail wireless backhauling for 5G cellular network,since the low expense and operation flexibility.To mitigate the interference between downlink backhaul and radio access,while guaranteeing the queue system stability,this paper proposed a Lyapunov-based dynamic ICIC algorithm.Firstly,we formulated a stochastic optimization problem to maximize the spectral efficiency,and transform it using the fractional programming theory.Then,based on Lyapunov optimization,the problem is modeled to jointly optimize the spectral efficiency and system stability.Finally,an interference-aware dynamic resource reuse and joint allocation algorithm(IDRRJA)is generated to solve it.In IDRRJA,multiple scheduling priority matrixes are calculated based on the current queue states and channel states,and based on these priority matrixes,each resource block(RB)can be categoried and allocated.The simulation results reveal that the proposed algorithm can maintain the network stability while reducing the amount of the required resources comparing to both full duplex(FD)and half duplex(HD)modes for small cells.