Interference Analysis And Implementation Of Heterogeneous Network On GNU Radio And USRP

With the development of communication technology in recent years, mobile data services showed explosive growth. However, the shortage of spectrum and base station resource are unable to meet the rapid growth of demand. Under such background, the new generation mobile communication technology 5G must meet this demand, as a result of which, the Heterogeneous Network (HetNets) technology emerges. There are different kinds of overlapping cells in Heterogeneous network, in which all network layers share the same spectrum. Heterogeneous Network can improve the coverage, network capacity and the user perception of the role. Low power nodes(LPNS) such as Femtocell, Pico andRelay are deployed within the coverage of the conventional macro base stations(MBSs) in Heterogeneous Network, which can greatly improve the spectral efficiency as they share the same spectrum. However, the frequency reuse of the MBSs and the LPNs results in severe co-channel interference(CCI). Therefore, analysis the downlink interference of heterogeneous network is very important.This thesis first introduces the characteristics of the network structure of Heterogeneous network, followed by discussions on the transmit power of each low power node, the deployment of the standard, as well as the same-layer and cross-layer interference. Then the basic principle and system flow of orthogonal-frequency division-multiplexing (OFDM) system are analyzed, and the synchronization algorithm of OFDM is presented.The same-layer and cross-layer interference will impact users’communication quality and reduce the throughput rate. A two-tier hierarchical heterogeneous network interference model is proposed in this thesis, where the locations of the MBSs are deterministic as 3GPP defined and the locations of the Femtos are distributed following a Poisson point process. Then closed form lower bound downlink outage probability of Macro tier and Femto tier is derived.Through system level simulation, the influence of transmit power and distribution density of femto on throughput rate, outage probability, interference characteristics is analyzed.Further, in this thesis, based on the results of system level simulation, we use the software radio platform GNURadio and USRP to realize the transmitter and receiver. On the basis of the analysis of the principles and internal structure of software radio platform, transceiver of OFDM is realized and the measurement results of transmitted and received signals are analyzed. Then according to system level simulation results of the downlink heterogeneous network, the LPNSinterference module is implemented based on the number and transmit power of LPNS and channel characteristics in the heterogeneous network. Finally the signal to interference ratio (SIR) of transceiver on software radio platform is compared with thatin the system level simulation in four kinds of heterogeneous network scenario toverify the correctness of the generated interference signals through GNURadio and USRP inthe heterogeneous network.