Subcarriers Requirement And Congestion Control Analysis Based On The Relay Cellular Network

OFDMA that evolves from OFDM and can realize the multiple access technology has widely been applied to 4G cellular network.In the OFDMA cellular network,the spectrum resources are divided into a set of narrow bandwidth subcarriers which are orthogonal to each other.In this thesis,the subcarriers requirement for each mobile terminal and congestion control based on the relay cellular network are researched respectively.First,the SIR is consided to measure the inter-cell interference.And the CDF is considered to calculate the number of subcarriers requirement for a mobile terminal.The results show that comparing with single-hop downlink OFDMA cellular network under the same simulation environment,the number of subcarriers requirement based on the relay cellular network obviously are less.After that,because intra-cell relay technology is limitation to reduce subcarriers requirement,inter-cell relay technology,which using inter-cell relay technology to relay mobile terminal from overloaded cell to light-load neighboring cell,is proposed.The results show the benefits gained from inter-cell relay in congestion control.When the neighboring cells are very lightly loaded,it is observed that the number of supported mobile terminals can be as high as 5 times the number of mobile terminals accepted if inter-cell relay is not allowed.It is shown that the introduction of relay technology can improve the capacity of OFDMA cellular network.The study results are useful for the system performance improvement,network architecture design,resources planning and call admission of the OFDMA cellular network.