Feasibility of Coordinated Transmission for HEW Month Year doc.: IEEE 802.11-13/xxxxr0 September 2013 Feasibility of Coordinated Transmission for HEW Date: 2013-09-16 Authors: Yunzhou Li, Tsinghua Univ. Yunzhou, Tsinghua

September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 Abstract This presentation discuss the feasibility of using coordinated transmission between adjacent APs for future WLAN networks. As a similar technique, CoMP in LTE has been introduced briefly. The potential gain derived from coordinated transmission has been analyzed, by comparison of LTE CoMP and coordinated transmission in WiFi and experiment results. Some simple coordinated scheme has been introduced. Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.

Background &Motivation September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 Background &Motivation With the increase of AP density, the inter-BSS interference will be the dominant obstacle for increase of area throughput. It is very difficult to work well If there existed a good path between adjacent two AP due to DL-UL interference between the two AP. Different from wired technologies; adding multiple APs in the same vicinity doesn’t help if Interference becomes a major issue for dense environment. 11-13-0098-00-0wng-802-11-looking-ahead-to-the-future-part-II Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.

The Feasibility of Coordination Transmission September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 The Feasibility of Coordination Transmission As showed in the following figure, Access Controller (AC) are widely used in practice AC can play a role of controller of coordination transmission between adjacent APs Yasuhiko Inoue (NTT), et. al.

The Feasibility of Coordination Transmission September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 The Feasibility of Coordination Transmission Enterprise is evolving towards a cloud-based model No longer files and information are stored on local machines Mobile access to cloud is expected to increase with the increase of smart mobile devices. Enterprise WiFi 11-13-0098-00-0wng-802-11-looking-ahead-to-the-future-part-II Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.

Coordinated Multi-Point (CoMP) transmission and reception In LTE September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 Coordinated Multi-Point (CoMP) transmission and reception In LTE Joint Transmission (JT) Simultaneous data transmission from multiple points (part of or entire CoMP cooperating set) to a single UE or multiple UEs in a time-frequency resource Dynamic point selection (DPS)/muting Data transmission from one point (within the CoMP cooperating set) in a time-frequency resource Coordinated Scheduling/Beamforming (CS/CB) Data for an UE is only available at and transmitted from one point scheduling/beamforming decisions are made with coordination among points corresponding to the CoMP cooperating set. Joint Processing (JP): Data for a UE is available at more than one point in the CoMP cooperating set (definition below) for a time-frequency resource 3GPP TR 36.819 Coordinated multi-point operation for LTE physical layer aspects Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.

September 2012 doc.: IEEE 802.11-12/xxxxr0 Joint Processing (JP): Data for a UE is available at more than one point in the CoMP cooperating set (definition below) for a time-frequency resource Yasuhiko Inoue (NTT), et. al.

The Difference between TD-LTE and WiFi for Coordinated Transmission September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 The Difference between TD-LTE and WiFi for Coordinated Transmission In cellular systems of TD-LTE, all the eNBs are synchronized in symbol and slot Whereas each AP in Wi-Fi systems decide to transmit/receive according to itself and don’t take care of other adjacent AP’s TX/RX. In addition, the deployment of eNB are chosen base on well-planning, which is very different from selection of AP’s position. Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.

The Difference between TD-LTE and Wi-Fi for Coordination Transmission September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 The Difference between TD-LTE and Wi-Fi for Coordination Transmission Besides, there is a significant difference in use of time and frequency block between cellular and Wi-Fi. Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.

Some Coordinated Transmission Schemes September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 Some Coordinated Transmission Schemes Integrated coordinated transmission mechanism with Wi-Fi networks All the time domain resource is divided into two categories: Coordinated TX/RX Intervals(CTRI) and Non-Coordinated TX/RX Intervals(NCTRI) which is scheduled and decided by coordination controller according to the amount of STA and their distribution IEEE 1588 & synchronization Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.

Some Coordinated Transmission Schemes September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 Some Coordinated Transmission Schemes Coordinated power allocation The scheme of AP selection is one of special case IEEE 1588 & synchronization Coordinated frequency band Coordinated power and frequency band Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.

Some Coordinated Transmission Schemes September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 Some Coordinated Transmission Schemes Coordinated frequency band allocation Joint dynamic allocation of frequency and power Which is the combining case of coordinated power allocation and coordinated frequency band allocation IEEE 1588 & synchronization Coordinated frequency band Coordinated power and frequency band Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.

Some Coordinated Transmission Schemes September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 Some Coordinated Transmission Schemes Joint Transmission based one joint precoding like SU-MIMO / MU-MIMO in 802.11ac The combing channel is and the precoding matrix is decided based on MU-MIMO can be combined to the scheme JT need high-resolution synchronization in time and frequency among the adjacent APs, which can be implemented by CPRI / IEEE 1588, etc. Coherent IEEE 1588 & synchronization Coordinated frequency band Coordinated power and frequency band Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.

Experiment of Multi-AP for Dense WLAN September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 Experiment of Multi-AP for Dense WLAN Each STA can detect multiple APs within its reception range. Logic Topology figure Coordinated frequency band Coordinated power and frequency band Yasuhiko Inoue (NTT), et. al.

Experiment of Multi-AP for Dense WLAN September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 Experiment of Multi-AP for Dense WLAN Strategies: In UL, multi-AP receive the STA’s signal simultaneously and check it by CRC. In DL, AC chooses one AP from multi-AP as transmit point according to channel condition and load balance. Real Topology in experiment Coordinated frequency band Coordinated power and frequency band StarEast Yasuhiko Inoue (NTT), et. al.

Experiment of Multi-AP for Dense WLAN September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 Experiment of Multi-AP for Dense WLAN Combining with optimal physical carrier sensing, more 100% gain can be achieved in both UL and DL. UL DL [1] Y. Zhu, Q. Zhang, Z. Niu, J. Zhu, “On Optimal Physical Carrier Sensing: Theoretical Analysis and Protocol Design”, IEEE INFOCOM2007 [2] Y. Zhu, Q. Zhang, Z. Niu, J. Zhu, “Leveraging Multi-AP Diversity for Transmission Resilience in Wireless Networks: Architecture and Performance Analysis”, IEEE Trans. Wireless Comm., 2008.4. Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.

Remarks on Coordination Gain September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 Remarks on Coordination Gain Although only about 15% gain from CoMP in LTE can be achieved, considerable gain from simple coordinated scheme has been showed in our experiment. In our opinion, the possible reason is CoMP gain in LTE derives from SINR increase for cell-edge UEs who are at low rates, so the contribution for the whole cell throughput is not considerable. However, the gain from coordinated transmission in WLAN is from the decrease of collision and resulting in the increase of transmission opportunity. IEEE 1588 & synchronization Coordinated frequency band Coordinated power and frequency band Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.

September 2012 doc.: IEEE 802.11-12/xxxxr0 September 2013 Summary It is feasible for integrating coordinated transmission in to WLAN for HEW by extending the role of AC. For analysis of potential gain, CoMP in LTE has been introduced briefly. Further, the difference between TD-LTE and WiFi for coordinated transmission has been summed up and some simple coordinated scheme has been introduced. Finally, the potential gain for HEW has been analyzed. IEEE 1588 & synchronization Coordinated frequency band Coordinated power and frequency band Yunzhou Li, Tsinghua Univ. Yasuhiko Inoue (NTT), et. al.