1. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-11-0504-00-0wng July. 2011 Jin Young Kim, Kwangwoon UniversitySlide 1 Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Cooperative Transmission for LED-ID Network ] Date Submitted: [10 July, 2011] Source: [Jin Young Kim, Yoon Hyun Kim, In Hwan Park, Jaesang Cha, Kyesan Lee, and Yeong Min Jang] [Kwangwoon University, Seoul National University of Technology, Kyunghee University, Kookmin University] Address [Kwangwoon University, Seoul, Korea] Voice:[82-10-5355-4825], FAX: [82-2-913-5006], E-Mail:[jinyoung@kw.ac.kr] Re: [] Abstract:[Some Considerations for Draft VLC Specification] Purpose:[Contribution to IEEE 802.15.7 VLC] Notice:This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15.

2. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-11-0504-00-0wng Slide 2 Contents Introduction - Shadow region problem in LED-ID Network Cooperative Transmission - Concept & Motivation - Performance of Cooperative Transmission Conclusion Jin Young Kim, Kwangwoon University July. 2011

3. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-11-0504-00-0wng Problem of LED-ID Network Jin Young Kim, Kwangwoon UniversitySlide 3 July. 2011 - If Reader 2 is out of tag’s network, it can not receive tag’s signal - Region of network for LED-ID is limited - Shadow region → decrease coverage → lower capacity

4. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-11-0504-00-0wng Discussion Current draft VLC specification bases on IEEE 802.15.4 Current draft VLC specification may consider cooperative transmission for problem of LED-ID Network. Jin Young Kim, Kwangwoon UniversitySlide 4 July. 2011

5. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-11-0504-00-0wng Slide 5Jin Young Kim, Kwangwoon University Concept & Motivation of Cooperative July. 2011 Cooperative communication in wireless networks. – They allow single-antenna mobiles to reap some of the benefits of MIMO systems. – Transmit diversity (mitigate fading) and coding gain (lower BER). In wireless cooperative networks, the wireless agents (users) may increase their effective quality of service (BER, Outage probability,…) via cooperation.

6. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-11-0504-00-0wng Slide 6 Advantages  Higher spatial diversity  Higher throughput  Lower delay  Reduced interference  Lower transmitted power  Adaptability to network conditions Cooperative Transmission Jin Young Kim, Kwangwoon University July. 2011

7. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-11-0504-00-0wng Slide 7 Types of Cooperative Transmission Jin Young Kim, Kwangwoon University July. 2011 Requirements for application –AF and multihop : existing system (repeater) –CC : change at both source and destination nodes –Network coding : changes at higher layers –CF : changes at destination node and extra CSI (Channel state information) Relay SourceDestination Amplify – and – Forward (AF) Detect – and – Forward (DF) Cooperative Coding (CC) Compress – and - Forward (CF)

8. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-11-0504-00-0wng Slide 8 Amplify-and-Forward (AF) Jin Young Kim, Kwangwoon University July. 2011 How it works – Amplify and retransmit – Decision is made at the Reader 2 Two independently faded versions of same signal, leading to diversity Inter-user channel coefficients are assumed to be known at the base station to do the optimal decoding

9. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-11-0504-00-0wng Jin Young Kim, Kwangwoon UniversitySlide 9 July. 2011 - We propose an expanding coverage method through cooperative transmission for network. -Using cooperative relay, Reader 2 can receive Tag’s signal → “Increasing” coverage, “Better” reliability → Boosting network capacity Cooperative Transmission for LED-ID systems

10. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-11-0504-00-0wng Slide 10 Cooperative Transmission Model Jin Young Kim, Kwangwoon University July. 2011 Received signal at the Reader 2;

11. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-11-0504-00-0wng Slide 11Jin Young Kim, Kwangwoon University July. 2011 Performance of Cooperative Transmission BER performance of cooperative transmission for LED-ID network Compared according to distance between Tag and Reader Using amplify-and-forward(AF) cooperative method

12. doc.: IEEE 802.15-xxxxx Submission doc. : IEEE 802.15-11-0504-00-0wng Slide 12 Conclusion We propose improved expanding LED-ID network coverage. Proposed Cooperative Transmission in cooperative network for LED-ID systems - Better reliability - High SNR - Increase channel capacity Jin Young Kim, Kwangwoon University July. 2011