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A High Spectral Efficiency System Enabled by Free Window Duplexing

A High Spectral Efficiency System Enabled by Free Window Duplexing. Bingli JIAO Professor and Dr. Peking University. Content. 1. Invention of SFST Duplex 2. Duplex Interference Reduction 2.1 A Dem. System 2.2 Interference Cancellation 3. Capacity issue.

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A High Spectral Efficiency System Enabled by Free Window Duplexing

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  1. A High Spectral Efficiency System Enabled by Free Window Duplexing Bingli JIAO Professor and Dr. Peking University

  2. Content 1. Invention of SFST Duplex 2. Duplex Interference Reduction 2.1 A Dem. System 2.2 Interference Cancellation 3. Capacity issue

  3. 1. Invention of SFST Duplex (IPR issue) 1.1 Concept （1） Frequency Division Duplex (FDD) The transmitted- and received signal of a node are allocated onto different frequency bands. （2）Time Division Duplex(TDD) The transmitted- and received signal of a node are allocated in different time slots. Bandwidth Efficiency is about ½ when consider the simplex in respect to the whole bandwidth. (3) Same time and same frequency duplex Same time and same frequency duplex (also called single channel full duplex ) allocates the transmitted- and received signals on same band and in same time slot. Thus, the bandwidth efficiency is 1, or doubled in comparison with FDD and TDD

  4. 1. 1. Concept Invention: Same Frequency and Same Time (SFST) slot duplex at BS and TDD at MSs System model Bandwidth Efficiency

  5. 1. 1. concept 2006年9月20日 , Bingli JIAO and William C.Y. LEE: 一种码分双工的通信方法；专利号：ZL 200610113248.4；专利申请 2006年完成专利申请， 2010年3月17日 授权 • 发明名称：一种适用于同频同时隙双工的干扰消除方法 • 申请单位：北京大学 • 摘要：本发明提供了一种干扰消除技术，使无线通信上下行链路能工作在同一频率和同一时隙，从而提高频谱利用率。当上下行信道同频、同时隙的情况下，下行链路对上行链路的干扰表现为本小区基站发射机和邻小区基站发射机对本小区基站接收机的干扰。本发明利用有线连接的方法将干扰信号送给接收机，在接收机中设置一个信号预处理单元，在射频上消除来自空中接口的发射机信号干扰。另外，本发明还提供了一种天线布放原则以减少发射机对接收机直接干扰的功率。本发明的干扰消除方法适用于同频同时隙双工系统，可大大节约频率资源和时间资源。 • 同一频率和同一时隙 • 小区基站发射机对基站接收机的干扰消除 • 射频干扰消除 • 特殊的天线布放原则

  6. 1. 1.Concept Title of Invention (2006 appl. 2010 authorized) An Interference cancellation Technique for Same Frequencyand Same Time slot duplex Affiliation and Inventors: Peking University, Inventor: Bingli JIAO and William Y.C,. LEE Abstract: This invention provides an interference cancellation technique to enable the UL and DL channel of BS working over same frequency and same time (SFST) slot。When UL and DL channel works over signal channel with SFST, the receiver of a BS can suffers from the interference of its BS transmitter and those of its neighboring cells. This invention uses line connection to transfer the interference to the receiver mentioned above and set an interference canceller to cancel the interferences coming • Same Frequency and Same Time Slot • BSs to BS Interference Cancellation • RF Cancellation • Antenna Placements

  7. 1. 1.concept Paper publication: VTC2009 Invited paper Later publication by • Stanford University J. Choi, M. Jain, K. Srinivasan, P. Levis, and S. Katti, ``Achieving single channel, full duplex wireless communication,'' in Proc. the 16th annual int. conf. Mob. Comp. and Networking, 2010. (2) Rice University M. Duarte, C. Dick, and A. Sabharwal, ``Experiment-driven characterization of full-duplex wireless systems,'' IEEE Trans. Wireless Commun., vol. 11, no. 12, pp. 4296--4307, Dec. 2012.

  8. 2. Duplex Interference Reduction 2.1. Development In 2013, a demo has been constructed to show the STSF BS in communication with two MS over cell coverage of 100 meters. .

  9. 2.1. Development Base Station

  10. 2.1. Development Video streaming and spectrum .

  11. 2. .2. fundamental problem RF- and digital cancellation 3~40dB Over 70dB Digital Cancellation RF Cancellation

  12. 3. Capacity Issue Shannon Channel Capacity C=H log[1+S/(I+N)] (1) In most cases of wireless communication system, “I” is a self Interference. SFSF uses an interferencecancellation to deal with “I” and thus, increases the channel capacity in a manner different from lots of conventional methods.

  13. 3.1. Capacity of the Proposed System

  14. 3. Capacity Issue For DL channel, MS-MS interference can be calculated by using 2-ray model (1) Assuming : , , leads a SIR of 24dB. Conclusion The MS-MS interference is not major problem, if we use scheduling method to optimum the distances among the two MSs in operation,

  15. 3. Capacity Issue For UL channel, we divide the bandwidth into small segments, and use Water-filling to each one where and are the SINRs of a frequency segment and the cut off value, is the probability density function.

  16. We refer the frequency segments having the SINR larger than the cut off value to as the free window and, thus, the duplex to as free window duplex (FWD) Bandwidth Gain Factor of FWD Capacity Gain Factor of FWD

  17. Raleigh Distribution where is the averaged SINR.

  18. Numerical results of bandwidth gain factor

  19. Numerical results of capacity gain factor

  20. Thanks! “3x!” “3Q!” 谢谢！

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