An Adaptive Bandwidth Allocation for Energy Efficient Wireless Communication Systems

In this paper, an energy efficient bandwidth allocation scheme is proposed for wireless communication systems. An optimal bandwidth expansion（OBE） scheme is proposed to assign the available system bandwidth for users. When the system bandwidth does not reach the full load, the remaining bandwidth can be energy-efficiently assigned to the other users. Simulation results show that the energy efficiency of the proposed OBE scheme outperforms the traditional same bandwidth expansion（SBE） scheme. Thus, the proposed OBE can effectively assign the system bandwidth and improve energy efficiency.

Cross-layer resource allocation based on equivalent bandwidth in OFDMA systems

A quality of service（QoS） guaranteed cross-layer resource allocation algorithm with physical layer, medium access control（MAC） layer and call admission control（CAC） considered simultaneously is proposed for the full IP orthogonal frequency division multiple access（OFDMA） communication system, which can ensure the quality of multimedia services in full IP networks.The algorithm converts the physical layer resources such as subcarriers, transmission power, and the QoS metrics into equivalent bandwidth which can be distributed by the base station in all three layers. By this means, the QoS requirements in terms of bit error rate（BER）, transmission delay and dropping probability can be guaranteed by the cross-layer optimal equivalent bandwidth allocation. The numerical results show that the proposed algorithm has higher spectrum efficiency compared to the existing systems.

CO-HCCA:Bandwidth Allocation Strategy in Internet of Vehicles with Dynamically Segmented Congestion Control

Hybrid coordination function controlled channel access(HCCA)applied in wireless ad hoc network systems is the strategy to allocate the bandwidth resources of control channel(CCH)and service channels(SCHs).With the continuous development of Internet of vehicles(IoV)technologies,it is difficult for HCCA to support traffic information services,such as low delay along with high-frequency dissemination of security beacons and large capacity interaction of image data.Fusing the fundamental theories of No.7 signaling system and 5G-IoV technologies,this paper proposes a novel channel bandwidth allocation strategy named CO-HCCA,which matches CCH time slot numbers with on board units(OBUs)numbers to reduce the congestion of channel access demand information(CADI);and also illustrates a dynamic segment adjusting algorithm of the time slots.On one hand,in the channel reservation stage of CCH control cycle,OBUs are sorted according to the priority of data transmission,and then the corresponding transmission slots are adopted orderly according to the OBUs numbers,so as to decrease the collision probability of high-frequency dissemination of CADI.On the other hand,for the quickly arriving and leaving OBUs in coverage of roadside base station(RBS),the prediction of bandwidth segments is dynamically adjusted to adapt to the time-varying characteristic of the connected vehicle scenarios.Modeling calculation and objective comparison on OMNeT++computing platform show that the proposed CO-HCCA strategy can effectively reduce the channel congestion of IoV,and in the scenario of high-density data interaction,it is beneficial to promote the transmission timeliness of security beacons and the package delivery rate(PDR)of high bit-rate multiple information.