Extending Design and Implementation of WiFiRe-MAC

1. Extending Design and Implementation of WiFiRe-MAC M.Tech. Project (stage 1) Ranjith Kumar Madalapu 05329R08 Under the guidance of Prof. Sridhar Iyer and Prof. Anirudha Sahoo Department of Computer Science and Engineering Indian Institute of Technology Bombay Mumbai

2. Motivation • Broadband Internet is an Enabling Technology. It can enable • Internet-based education, transactions, entertainment • job creation • economic / GDP growth of country • Massive broadband penetration into Indian homes will helps to achieve these goals. • We need Low-Cost solutions • Around 75% Indian population is living in suburban and rural villages and their income is <$3000 per year [7]. • They can spend at most Rs. 300/- per month. • We need Long-Range communication • Villages are sparsely located (spaced 2-3 km apart) • Need to cover 15-20 km from fiber PoP. • It require high gain antennas of at-lest 150 dB[7]. • India has good market conditions too. • About 50 millions households [7] to be the potential market for Internet. • This numbers may increase once income level of the people is increase. CSE Dept., IITBombay

3. Example Max data rate possible in WiFiRe cell = 25Mbps (UL + DL) with spectral reuse Min rate required for Broadband connection = 256kbps at kiosk[1] Max STs we can serve = 25M/256k = 100 approx Assume each ST has 3 connections and everyone paying Rs. 300 per connection then total revenue per year = 100 x 3x 300 x12 = 1 million approx According to CEWiT[7] calculations 1 million is a good revenue for the operator in a sector with 300 subscribers which will cover all CAPEX and OPEX. Similarly in our case we assumed total cell is under single operator. Therefore WiFiRe is a good business model. It can provide Broadband Internet connection to sparse located areas, specially for rural India. CSE Dept., IITBombay

4. General Problem Statement Our goal is to build a system which can have capable of providing Broadband Internet (min 256 kbps [1] at kiosk) over long ranges at cheapest possible cost by using present available technology. CSE Dept., IITBombay

5. WiFiRe model • WiFiRe – WiFi Rural extension • WiFiRe = WiFi PHY + WiMAX MAC • Operating at conditional free license band spectrum (2.4 GHz) • Cover 15 km radius with LoS outdoor communication • Using single WiFi carrier (20 MHz) we can achieve up to 11Mbps data rate with system gain of 132 dB. • By using spectral reuse estimated data rate is 25 Mbps (uplink + downlink) per cell. • It require 40m tower at BS near PoP and 10m pole at each ST to maintain 150dB gain. • Model use Sectorized antennas at BS and Directional antennas at ST. • Single MAC controller for all sectors in S • MAC mechanism is TDD-MSTDM Fig: WiFiRe Network Configuration[1] CSE Dept., IITBombay Fig: Medium Access Connection in WiFiRe[1]

6. Assumptions [1] • Existence of a fiber PoP at every 25 km for backbone connectivity • WiFi chipset are designed so that the PHY and MAC layers separate • There is a fixed carrier freq fc and WiFi radios are operating at 11Mbps except for PHY sync • 20 MHz (1 carrier) of conditional licensed spectrum in the 2.4 GHz band is available for niche/rural areas. • PHY overhead is 192 micro sec for 1 Mbps and 92 micro sec for 2 and 11 Mbps • Wireless links in the system are fixed, single hop, with a star topology • No multi path issues due to deployment topology and LoS design • All transmissions in a cell are controlled by single scheduler at ‘S’ • Various components in the system have unique IP address • A single VOIP packet is approximately 40 bytes. • Ex: codec G.729, having sampling rate of 8 kbps with 20 ms duration of each sample CSE Dept., IITBombay

7. Problem Definition • Goal is to implement MAC specification for the WiFiRe • This includes implementation of different modules relating to P2P and PMP modes, providing QoS, maintaining database and importing into actual hardware. • Some modules in the MAC is all ready implemented in first phase. We are trying to add some/all of the missing modules to existed implementation. • Goal is to show a full fledged working demo of WiFiRe. CSE Dept., IITBombay

8. Intel PRO/Wireless 5116 Broadband wireless Interface [9] • Implemented based on IEEE 802.16d-2004 design draft. • Highly integrated System on Chip (SoC) will work in both licensed and license-exempt radio frequency. • Used dual-core processor architecture provide flexibility and programmability for the MAC and software applications. • Chip build around a high-performance OFDM modem. • This chip can deliver high-rate IP-based data, voice, and real-time video. • Channel bandwidths and data rates are programmable. • Integrated with 10/100 MAC, inline security, and a TDM controller interface. • 360-pin chip supporting temperatures ranging from -40 to 85 C. CSE Dept., IITBombay

9. Present status of W5116 MAC • It supports only P2P connection between BS and SS. • Ranging, simple broadcast and FCFS scheduler is done. • Map generator, classifier, DSx, multicasting, contention, CAC are yet to be implement. • No support of QoS • No contention and polling support What I did at Intel? • Introduction of New Burst called ‘Contention’ burst[2] • Contention resolution by using std. Back-off algorithm • Handling different CID tables • Allocating new CIDs and STIDs for new incoming flows CSE Dept., IITBombay

10. QoS service classes supported by WiFiRe • Unsolicited Grant Service (UGS) : Fixed-size data packet at a constant bit rate (CBR). Ex: VoIP • Parameters includes max sustained traffic rate, max latency, tolerated jitter and request/transmission policy. • Real time polling Service (rtPS) : Variable-size data on a periodic basis. Ex: MPEG • Parameters includes min reserved traffic rate, max sustained traffic rate, max latency and request/transmission policy • Non real time Polling Service (nrtPS) : Delay tolerant data stream i.e. variable-size data grants at a min guaranteed rate. Ex: FTP • Min reserved traffic rate, max sustained traffic rate, traffic priority and request/transmission policy. • Best Effort Service (BE) : Support data streams which don’t require min service level guarantee. Ex: Web browsing • Max sustained traffic rate, traffic priority, and request/transmission policy • BW grant types in WiFiRe: GPST, GPC, GPSF CSE Dept., IITBombay

11. Present status of WiFiRe Real System Component : Fig: Proposed WiFiRe Real system components [4] CSE Dept., IITBombay

12. LAN Emulation : Test bed which will test P2P connection in WiFiRe • Assumptions: • - IP addresses and ARP cache entries are assumed to be statically assigned. • - No special authentication method for upcoming ST is being deployed on BS • No BW change request • No QoS support • Clients allowed to access service only when ST is in registered (REGD) state. Fig: LAN Emulation test bed for P2P[4] Scheduling: Simple Round Rabin scheduling for UL and FCFS for DL is used. CSE Dept., IITBombay

13. Meta Frame Creation and Insertion : Fig: Consecutive allocation of slots with optimized control packet CSE Dept., IITBombay

14. Modules Yet to be Implement • Ranging • Importing MAC software into actual Hardware • Packet classifier • Type of Grants (GPSS, GPC or GPF) • Providing QoS • Connection type classifier • Call Admission Control • UL Scheduler • Dynamic service change (DSC) • Support for PMP mode • Multicast transmission support • Contention and Polling • Maintaining Network Statistics CSE Dept., IITBombay

15. Solution Outline Implementing and testing MAC software for WiFiRe. Problems which I have interested to solve is as follows • P2P working demo • Implementing Meta Frame • Importing into actual hardware • PMP working demo • Multicast Transmission • Contention and Polling CSE Dept., IITBombay

16. Proxy server HUB1 ST1 Client11 Eth0 Eth1 Client12 BS1 Client 1x Eth0 Eth1 SWITCH1 . . . . . . . . . . . . . . Client n1 STn Eth0 Eth1 Client n2 Client ny HUB2 Test bed for PMP mode Fig: proposed PMP test bed model for WiFiRe CSE Dept., IITBombay

17. Packet Classifier Using 802.1Q (0x8100) packet TAG header • Priority ={Background, Spare, Best Effort, Excellent Effort , Controlled Load, Video, Voice, Network Control } • Assumption is all incoming traffic is 802.1Q packets. • Only GPST or GPSF is possible to implement, GPC will not possible???? Packet Classification on multiple fields CSE Dept., IITBombay

18. Meta Frame Implementation : Fig: Consecutive allocation of slots with optimized control packet CSE Dept., IITBombay

19. Multicasting, Contention and Polling : We want to follow standard mechanism for implementing Multicasting, Contention and Polling. Multicasting : by assigning single valid CID for multicast packet and transmitting into wireless medium. The ST has a list of multicast CID which it belongs to. If CID is matched then ST will read the packet. Same CID will be used for transmitting packet. Contention : Standard Back-off algorithm will be used for resolving contention among STs. Possible unit for count is ‘slot’. In contention period all STs should wait a random number of slots before actual transmission. Polling : When ever BS have BW, it polls ST either randomly or in FCFS basis. CSE Dept., IITBombay

20. Timelines CSE Dept., IITBombay

21. Conclusion By considering above solution strategies I will implement the listed WiFiRe MAC software and I will test by using WiFiRe PHY hardware. CSE Dept., IITBombay

22. References [1] Sridhar Iyer, Krishna Paul, Anurag Kumar, Bhaskar Ramamurthy, WiFiRe: Medium Access Control (MAC) and Physical Layer (PHY) Specications, CE-WiT, India, Aug 2006. [2] LAN/MAN standards Committee, and IEEE Microwave Theory and Techniques Society, Part 16: Air Interface for Fixed Broadband Wireless Access Systems, IEEE-SA Standards Board, June 2004. [3] LAN/MAN standards Committee, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specications, IEEE-SA StandardsBoard, June 2003. [4] Sameer Kurkure, Shravan Kumar, Design and Implementation of WiFiRe MAC protocol, M.Tech Technical Report, IITBombay, India, July 2007. [5] Chi-Hong Jiang, Tzu-Chieh [ref] Tsai, Token Bucket Based CAC and Packet Scheduling for IEEE 802.16 Broadband Wireless Access Networks, National Chengchi University, Taipei, Taiwan, ROC 2006. [6] Pankaj Gupta and Nick McKcown, Packet Classication on Multiple Fields, Computer Systems Laboratory, Stanford University, Stanford. [7] Interim (3.5G) Broadband Wireless System for INDIA : Framework, Requirements, Performance needs, CEWiT-2005, march-2005. [8] Lidinsky, W., IEEE Standard P802.1Q IEEE Standards for Local and Metropolitan Area Networks: Virtual Bridged Local Area Networks (VLAN), 30.7.1998 [9] Intel WiMAX Product, Intel PRO/Wireless 5116 Broadband Interface Innovation for WiMAX xed wireless broadband platforms from http://www.intel.com/network/connectivity/products/wireless/307327.pdf,15/6/2007. CSE Dept., IITBombay

23. Thank You CSE Dept., IITBombay