D2D Network Communication Key Technologies

The growing business needs of the local data sharing put forward higher requirements to IMT-Advanced system coverage and service flexibility,when the base station as the center,the service delivery model to adapt to development of local business showed obvious limitations.D2D(Device-to-Device)communication is the local user communication does not require data forwarding through the base station,but in such a close range,the data transmission through direct link of device-to-device.The introduction of D2D communications can effectively enhance the cell coverage and improve transmission performance.First D2D communication background were introduced,including the architecture,the gain and the advantages of D2D communication;we overview the key technologies D2D communication.In the cell,D2D communications can be multiplexed mode cell cellular link with other cellular link coexist,can also assign exclusive band communication.In different scenarios,D2D communication may be advantageously selected communication mode.Meanwhile,the base station Allocates subchannel of D2D communication in multiplexed mode and cellular communication distance multiplexing can reduce interference between each other,enhance the throughput of the entire system.power control is one of the key technologies D2D communication,in this thesis we outlines how D2D power control,including static and dynamic power control in two parts.Secondly,this thesis studied the frequency set options in D2D communication.First we create multiplexing communication system model under the time-frequency resource and introduce the cellular communication composition.Throughput program based in greed,the base station only consider local conditions,the maximum throughput of each selected device to reuse the corresponding link,part time and frequency options intelligently selects the ratio of D2D link and the cellular communication link resources,to meet threshold of cellular link SINR and D2D link SINR.This thesis presents a interference randomized frequency set options based on chaotic sequence,the base station compares D2D better channel in each channel link status,the higher the probability of selecting a better channel link status,and interference randomization to ensure that the communication quality of the cellular link.Finally we study data sharing programs within the D2D network cluster.For some devices have the same needs and the close proximity of each others can be composed as a D2D network cluster communication.For conventional multicast communication,a multicast rate is limited by the worst of all the receiving device channel link status.In D2D network clusters,we can take advantage of the characteristics of clusters D2D network for auxiliary data transmission.Determined based cluster sharing scheme within the relay by transmission loss function within the cluster and identifying the relay device within the cluster,based on maximizing the outage capacity transmission scheme through the system outage capacity to allocate transmission equipment.This thesis presents a consideration fountain code properties of the cluster head dynamic option,sends the data to be transmitted through the fountain,breaking the bottleneck of multicasting,the selection of the throughput of the largest equipment in so successfully received equipment to become cluster head,reducing entire cluster all devices successfully received time.