1 / 17

Spatial Reuse and Interference Mitigation in 60 GHz

Spatial Reuse and Interference Mitigation in 60 GHz. Authors:. Date: 2009-07-14. Introduction and Goals. As described in [2], channel access in 60GHz will use directional communication

yana
Download Presentation

Spatial Reuse and Interference Mitigation in 60 GHz

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Spatial Reuse and Interference Mitigation in 60 GHz Authors: Date: 2009-07-14 Carlos Cordeiro, Intel

  2. Introduction and Goals • As described in [2], channel access in 60GHz will use directional communication • As a result, there is a big potential to exploit spatial reuse in 60GHz and increase the spectrum efficiency • This becomes even more important in those regulatory domains with a single 60GHz channel (e.g., Australia) • On the flip side spatial reuse may also increase interference, since a higher number of links will operate simultaneously and may interference with each other • Therefore, in this presentation we: • Introduce spatial reuse and the potential it holds in 60GHz • Propose that TGad provides means for spatial reuse and interference mitigation in 60GHz Carlos Cordeiro, Intel

  3. What is spatial reuse? • Spatial (Frequency) Reuse = Two or more links sharing the same frequency channel in the same spatial vicinity at the same time Example in the office Example in the home STA 1 STA 2 PCP STA 4 STA 3 Spatial reuse within one BSS/PBSS [1] Spatial reuse across neighboring BSS/PBSS [1] Carlos Cordeiro, Intel

  4. Example usage models [3][4] which can take advantage of spatial reuse • Wireless networking for small office (usage 2d in [3]) • Multi-media mesh backhaul (usage 4a in [3]) • Hotspot, enterprise, small Office or home, campus-wide deployments, municipal deployments • Enterprise cubicle [4] The Enterprise Cubicle [4] Carlos Cordeiro, Intel

  5. Recap of [1]: the Personal BSS and high-density environments • To support several key TGad usages [3] and cope with directional communication in 60GHz, the Personal BSS (PBSS) was introduced in [1] • PBSS is an extension of the IBSS • PBSSs are logical and “unmanaged” networks • Not defined by physical proximity (e.g., as it is typical in a BSS), and hence there can be multiple PBSSs in the same vicinity • Typically not managed by an authority with global information (e.g., IT department) • Thus, PBSSs can lead to a highly dense environment • Number of interfering links >> the number of available 60GHz channels (e.g., enterprise cubicle [4]) • Important TGad usages require a high spectrum efficiency and interference mitigation mechanisms Carlos Cordeiro, Intel

  6. Assessing the spatial reuse gain (1) • Goal: compare the potential of spatialreuse with omni and directional communication • Topology • Enterprise cubicle [4] • 9 cubicle office space, each office hasone randomly placed link • Simulation parameters • Transmit power = 10 dBm • Square ant. array (random orientation) • No. of ant. elements = 1 (omni) and 16 (directional) • NF=8 dB, implementation loss = 2dB • 5 reflectors/cube (2 dB reflection loss) • Penetration loss of partition wall = 3 dB* • Methodology • Links are added to the office as long as the SINR of active links do not drop below a prescribed SINR Threshold * This is based on internal channel measurements, which revealed that the penetration loss of a cubicle wall ranges from -3~-1 dB Carlos Cordeiro, Intel

  7. Assessing the spatial reuse gain (2) • Spatial reuse through directional only communication can provide up to 5 times performance gain over omni communication SINR Threshold = 20dB SINR Threshold = 10dB Spatial reuse gain Spatial reuse gain Carlos Cordeiro, Intel

  8. The Impact of Spatial Reuse on Interference • Spatial reuse provides large gain, but may also lead to increased interference • To evaluate this, we have setup a simple MAC simulator in OPNET • No “multiple access” (only 2 STAs per link and per PBSS) • The Antenna/RF model of this simulator is the same as in [5] • The simulator implements the partition-based path loss model [6] Carlos Cordeiro, Intel

  9. Simulation parameters • PHY: • Antennas: • PCP [1]: 36 antenna elements • STA: 16 antenna elements • TX_Power: 10dBm output power • PHY_Rate (fixed, no real time link-adaptation) • PHY rate of 3.8 Gbps used for directed data transmission • PHY rate of 0.9Gbps used for directed control transmissions • Beacon is transmitted with an effective rate of 2.5Mbps • MAC: 16msec beacon interval • Traffic: each PBSS has one flow which sends data at 751 Mbps CBR traffic rate Carlos Cordeiro, Intel

  10. Example: Spatial Reuse (1) PBSS 1 “on” times PBSS 2 PBSS 1 1m PBSS 2 “on” times 1m time Transmissions on top of each other: allowing spatial reuse • The two PBSSs can achieve spatial reuse with good throughput and no packet drop CBR=Constant Bit Rate Carlos Cordeiro, Intel

  11. Example: Interference impact (2) PBSS 1 “on” times PBSS 2 PBSS 1 1m 1m PBSS 2 “on” times 1m time STA in PBSS 2 moved to a different location Transmissions on top of each other: causing interference • PBSS 1 suffers significant throughput degradation due to interference from PBSS 2 • Also leads to higher power consumption and latency Carlos Cordeiro, Intel

  12. How to mitigate the interference impact? Some options • Several mechanisms are possible to mitigate interference such as channel switching and power control • In addition, there are options which are access scheme dependent. For example: • Random access inherently adapts to the available bandwidth (there are challenges to this in 60GHz though [2]) • For scheduled access, re-scheduling on the basis of interference may be used • Or a combination of an access scheme dependent option with power control and/or channel switching Carlos Cordeiro, Intel

  13. Example: Interference mitigation in scheduled access PBSS 1 “on” times (after re-scheduling) PBSS 2 PBSS 1 1m PBSS 2 “on” times (after re-scheduling) 1m 1m time Time-sharing the channel • STAs in PBSS 1 detect the interference and re-schedule their links • This helps the performance of PBSS 1 to recover • If security is not a concern, PBSS 1 and PBSS 2 could also be merged Carlos Cordeiro, Intel

  14. Conclusions • Directionality makes spatial reuse a natural characteristic in the 60GHz band • TGad should define means to enable interference mitigation and exploit spatial reuse in order to: • Take advantage of directionality in 60GHz • Satisfy the needs of important usage models (e.g., high-density scenarios such as enterprise cubicle) • Better utilize the limited number of channels available in the 60GHz spectrum • Substantially increase network capacity Carlos Cordeiro, Intel

  15. References [1] C. Cordeiro et al., 802.11-09/0391r0 [2] S. Shankar et al., 802.11-09/0572r0 [3] A. Myles and R. de Vegt, 802.11-07/2988r3 [4] E. Perahia, 802.11-09/296r6 [5] M. Park et al., 802.11-09/559r0 [6] C. R. Anderson and T. S. Rappaport, “In-Building Wideband Partition Loss Measurements at 2.5 and 60 GHz,” IEEE Trans. on Wireless Comm., Vol. 3, No. 3, May 2004, pp922-928. Carlos Cordeiro, Intel

  16. Backup Carlos Cordeiro, Intel

  17. PHY rate=4Gbps for SINR ≥ 20 dB PHY rate=2Gbps for 10 dB ≤ SINR < 20dB PHY rate=6Gbps for SINR ≥ 20 dB PHY rate=2Gbps for 10 dB ≤ SINR < 20dB Assessing the spatial reuse gain in terms of aggregate throughput Carlos Cordeiro, Intel

More Related