Research On Non-cooperated Reception In LTE TDD

In the field of information technology to intercept reconnaissance technology system, the non-cooperation of the wireless signal receiver technology is an important and crucial part. With the development of LTE, and the popularity of MIMO-OFDM technology, and the use of beamforming technology, the modern wireless communication system has developed some features such as high-speed, low-power, high security and others, because of these features a lot of difficulties have been brought to the non-cooperation of the wireless signal reception. As a non-cooperated receiver in today’s LTE environment, how to eavesdrop better quality of user’s signal and then to decode the user’s information of downlink, is the main studies of this paper.First, in order to demonstrate the system model of this study, the paper describes the development of LTE TDD system, and compare the advantages with FDD systems. Then the Chapter II then describes the model of the environment and the key technologies of the LTE standard under article is based, including macro path loss channel model, the relationship between the channel adaptive coding and modulation quality indication(CQI) and the modulation and coding scheme(MCS) is. In the second chapter, it is made in a non-cooperative reception environment that the user makes the MCS legitimate use as critical listening party are similar or identical to the difference between the SNR controlled within a certain range, and thus ensure that both have the same CQI or similar, so you can meet the requirements by CQI-MCS mapping. In the last second chapter describes the current status of non-cooperative receiver technology research and major issues facing a certain statement of research background.Secondly, under the research background, in the Chapter III the paper simplely introduces two common beamforming method LTE standard, which is based on SVD algorithm or GMD algorithm. This paper studies the cell environment, the base end of the pre-coding technique using downlink SVD algorithm is based on beamforming technology. Then without considering the case of path loss, for a single user in a single memory cell, the discussion of the listener can be studied in two different situations under a single antenna and dual antenna is proposed by the uplink pilot interference users, to change the base station side upstream channel estimation results, thereby affecting the ideological base station downlink beamforming algorithm to improve the success rate of non-cooperation received by the listener side.By the end of the discussion section of Chapter III extended and further analysis, considering LTE macro path loss situation, as non-cooperative in order to achieve the recipient to ensure that the channel quality indicator and CQI legitimate users of unity, and thus achieve between coherent modulation and coding scheme(MCS), the paper presents a non-cooperative receiver needed to achieve the goal: that is, under the listener side as far from a legitimate user conditions by means of the use of non-cooperative receiver listens to ensure that users in unable to detect the presence of the listener side(SNR≤2dB), and the case was disturbed legitimate user listens SNR and signal to noise ratio of the difference between the parties less 1.75 dB. This ensures that in the downstream receiver, the downlink signal calculation listening party received by estimating the obtained channel quality indication with the legitimate user by calculating the downlink reference signal obtained by the channel quality indication same, or simply away from a level so as detection listen parties selected by CQI MCS on the legitimate user is basically the same, and thus be able to properly restore the downlink information.Under the conditions that needed to meet the target, and based on the user’s uplink interference pilot ideas, through the study of non-cooperation in the listener receives this paper proposes three possible technical methods, which are interfereing the pilots with white noise, interfereing the pilots with the factor of weight pilots and interfereing the pilots with the factor of ratio pilots. The theoretical derivation is given in the same respectively shows the corresponding simulation results, wherein the pilot interference based on the white noise method is the easiest to implement, but poor performance. the scale factor method’s performance achieved under the highest degree of complexity, and need to know within the district pilot program using the legitimate user receives the uplink channel information, but listening party with the same conditions as the best transmit power,, but with comparison, only need to know the plot of the pilot sequence to its implementation complexity and performance. The Chapter IV also analyzes and compares the advantages and disadvantages between the three methods by simulation and also proved the proposed method can achieve the desired objectives.Finally, the Chapter V summerizes the full research work, and points out the next step possible research directions.