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Implications of usage models on TGad network architecture. Authors:. Date: 2009-03-11. Abstract. This presentation discusses existing 802.11 network architectures and how well they match TGad usages. It then proposes an enhanced network architecture for TGad. Introduction.
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Implications of usage models on TGad network architecture Authors: Date: 2009-03-11 Carlos Cordeiro, Intel Corporation
Abstract This presentation discusses existing 802.11 network architectures and how well they match TGad usages. It then proposes an enhanced network architecture for TGad. Carlos Cordeiro, Intel Corporation
Introduction • The usages submitted by the WFA to VHT-SG (IEEE 802.11-07/2988r4) include several usages with a different nature than popular 802.11 usages (e.g., web browsing, backup) • Therefore, one of the most basic issues TGad needs to address is the network architecture it will adopt in support of these new usages • BSS only, IBSS only, both, other? • To answer this question, we need to revisit the possible usages of TGad Carlos Cordeiro, Intel Corporation
Usage Models Taken from IEEE 802.11-07/2988r4: Arranged by Category Carlos Cordeiro, Intel Corporation
Usage Models Taken from IEEE 802.11-07/2988r4: “Rank-Ordering for the 2 Example Dimensions” Carlos Cordeiro, Intel Corporation
Key observations from top 3 WFA usages 1c: In room gaming • Usages are peer-to-peer (ad-hoc) in nature • No device is dedicated for a particular function • All devices in the network perform the role of a content consumer or content creator or both • Some of the devices limited by battery power • Access to WLAN infrastructure may not be required in all cases • For all usages under the ‘Wireless Display’ category (1), WFA (IEEE 802.11-07/2988r4) states that “the wireless network used for <usage> may or may not be part of the other operational WLAN network” 3a: Rapid sync-n-go file transfer (figure on left from IEEE 802.11-07/2988r4) 1b: Projection to TV or projector in conf. room (aka in room projection from PC to TV) Carlos Cordeiro, Intel Corporation
The 802.11 IBSS architecture • IBSS allows peer-to-peer communication without any need for a dedicated device like an AP • TGz addresses peer-to-peer between STAs, but requires an AP • Hence, IBSS is well suited to support the top 3 (and other) WFA usages • In the IBSS any STA has the ability to transmit beacons, but only one STA successfully transmits it in a beacon interval • Beacon serves as a kind of rudimentary scheduling • However, due to directionality in 60GHz [1]-[6], we need to reconsider the IBSS architecture 802.11 IBSS Architecture STA 1 STA 2 Beacon STA 3 Carlos Cordeiro, Intel Corporation
The 802.11 TGad Personal IBSS (PBSS) architecture • Directionality in 60GHz makes CSMA/CA access of limited use [1]-[6] • A future presentation will address the channel access issues in 60GHz • Therefore, we believe that IBSS needs to be enhanced as to introduce network coordination for better support of WFA usages in 60GHz • Improved power saving, QoS support, support to directional communication, spectrum management, etc. • The PBSS may not be part of the “other operational WLAN network” • There is no DS behind the PBSS/IBSS (To DS and From DS fields set to 0 in all data frames, including those to the PCP) 802.11 TGad PBSS Architecture STA 1 STA 2 Beacon STA 3 (PCP = PBSS Control Point) Carlos Cordeiro, Intel Corporation
Conclusions • The IBSS architecture incorporates important characteristics to meet the requirements of key WFA usages • BSS architecture can still support certain WFA usages • However, due to the directionality, channel access and other limitations imposed by operation in 60GHz, the IBSS architecture needs to be enhanced • A Personal IBSS (PBSS), managed by a PBSS Control Point (PCP), can be defined to better cope with directionality, QoS, power saving, spectrum management, etc., and hence appropriately support important WFA usages • A future presentation will address the channel access issues in 60GHz Carlos Cordeiro, Intel Corporation
References [1] C. Cordeiro et al., Ad Hoc & Sensor Networks: Theory and Applications, 650pp, ISBN 981-256-681-3, World Scientific Publishing, March 2006. [2] R. Ramanathan et al., “Ad Hoc Networking With Directional Antennas: A Complete System Solution,” IEEE Journal on Selected Areas in Communications, vol. 23, No. 3, Mar. 2005. [3] R. Ramanathan, “On the Performance of Ad Hoc Networks with Beamforming Antennas”, ACM MobiHoc, 2001. [4] R. Choudhury et al., “Using Directional Antennas for Medium Access Control in Ad Hoc Networks,” ACM MOBICOM, 2002. [5] L. Bao et al., “Transmission Scheduling in Ad Hoc Networks with Directional Antennas,” ACM MOBICOM, 2002. [6] T. Korakis et al., “A MAC Protocol for Full Exploitation of Directional Antennas in Ad Hoc Wireless Networks,” ACM MobiHoc, 2003 Carlos Cordeiro, Intel Corporation