wi -max is the best topic of seminar pesentation.

2.  What is WiMAX
 802.16 Introduction
 802.16 MAC Highlights
 MAC Convergence Sub-Layer (CS)
 MAC Common Part Sub-Layer (CPS)
 Advantages/disadvantages
 Future of WiMAX
 Questions

3.  Worldwide Interoperability for Microwave Access
(WiMAX) is the common name associated to the
IEEE 802.16a/REVd/e standards.
 These standards are issued by the IEEE 802.16
subgroup that originally covered the Wireless Local
Loop technologies with radio spectrum from 10 to
66 GHz.

4. Coverage range up to 50km and speeds up to
70Mbps(shared among users).

5. Sridhar IyerIIT Bombay 5

6.  Goal: Provide high-speed Internet access to home and
business subscribers, without wires.
 Base stations (BS) and subscriber stations (SS)
 Centralized access control to prevents collisions
 Supports applications with different QoS requirements
 WiMAX is a subset of IEEE 802.16 standard
6

7.  Provide efficient transport of heterogeneous
traffic supporting QoS
 Capable of broadband transmissions (2-75
Mbps)
◦ Accommodate both continuous and bursty traffic
 Mobile extensions: 802.16e
Wireless Networks Spring
2007

8.  SS has 48-bit IEEE MAC address
 BS has 48-bit base station ID
◦ Not a MAC address
◦ 24-bit operator indicator
 16-bit connection ID (CID)
 32-bit service flow ID (SFID)
 16-bit security association ID (SAID)

9.  ATM Convergence Sub-Layer:
◦ Support for VP/VC switched connections
◦ Support for end-to-end signaling of dynamically created
connections
◦ ATM header suppression
◦ Full QoS support
 Packet Convergence Sub-Layer:
◦ Initial support for Ethernet, VLAN, IPv4, and IPv6
◦ Full QoS support

10.  Functions:
◦ Classification: mapping the higher layer PDUs (Protocol
Data Units) into appropriate MAC connections.
◦ Payload header suppression (optional)
◦ MAC SDU (Service Data Unit), i.e, CS PDU, formatting
Packet PDU
(e.g., IP packet, Ethernet Packet)
PHSI
MAC SDU = CS PDU
Payload Header Suppression Index
Optional, Depending on upper layer
protocol

11.  Each SS has 3 management connections in each direction:
◦ Basic Connection:
 short and time-urgent MAC management messages
 MAC mgmt messages as MAC PDU payloads
◦ Primary Management connection:
 longer and more delay tolerant MAC mgmt messages
 MAC mgmt messages as MAC PDU payloads
◦ Secondary Management Connection:
 Standard based mgmt messages, e.g., DHCP, SNMP, …etc
 IP packets based CS PDU as MAC PDU payload

12.  Three components of 802.16 QoS
◦ Service flow QoS scheduling
◦ Dynamic service establishment
◦ Two-phase activation model (admit first, then activate)
 Service Flow
◦ A unidirectional MAC-layer transport service characterized by a set of QoS
parameters, e.g., latency, jitter, and throughput assurances
◦ Identified by a 32-bit SFID (Service Flow ID)
 Three types of service flows
◦ Provisioned: controlled by network management system
◦ Admitted: the required resources reserved by BS, but not active
◦ Active: the required resources committed by the BS

13.  UGS: Unsolicited Grant Services
 rtPS: Real-time Polling Services
 nrtPS: Non-real-time Polling Services
 BE: Best Effort

14.  UGS: Unsolicited Grant Services
◦ For CBR or CBR-like services, e.g., T1/E1.
◦ The BS scheduler offers fixed size UL BW
grants on a real-time periodic basis.
◦ The SS does not need to send any explicit
UL BW req.

15.  rtPS: Real-time Polling Services
◦ For rt-VBR-like services, e.g., MPEG video.
◦ The BS scheduler offers real-time, periodic, UL BW
request opportunities.
◦ The SS uses the offered UL BW req. opportunity to
specify the desired UL BW grant.
◦ The SS cannot use contention-based BW req.

16.  nrtPS: non-real-time polling
services
◦ For nrt-VBR-like services, such as, bandwidth-intensive
file transfer.
◦ The BS scheduler shall provide timely (on a order of a
second or less) UL BW request opportunities.
◦ The SS can use contention-based BW req. opportunities
to send BW req.

17.  BE: Best Effort
◦ For best-effort traffic, e.g., HTTP, SMTP.
◦ The SS uses the contention-based BW
request opportunities.

18.  Two types of Contention based UL
slots
 Initial Ranging
 Used for new SS to join the system
 Requires a long preamble
 BW Request
 Used for sending BW req
 Short preamble
 Collision Detection and Resolution
 Detection: SS does not get the expected response
in a given time
 Resolution: a truncated binary exponential backoff
window

19.  A Layer-2 sliding-window based flow control mechanism.
 Per connection basis.
 Only effective to non-real-time applications.
 Uses a 11-bit sequence number field.
 Uses CRC-32 checksum of MAC PDU to check data errors.
 Maintain the same fragmentation structure for
Retransmission.
 Optional.

20.  Two Major Functions:
◦ Secures over-the-air transmissions
◦ Protects from theft of service
 Two component protocols:
◦ Data encryption protocol
◦ A client/server model based Key management protocol
(Privacy Key Management, or PKM)

21.  Wimax Coverage
 Wimax High Speed
 Multi-functionality within Wimax Technology
 Wimax, cheap network
 Wimax Rich Features
 Smart antenna and Mesh Topology
 Ultra wide Band

22.  Lack of Quality
 Wimax range
 Wimax Bandwidth
 Expensive network
 Bad Weather
 Power consuming
 Data Rate

23.  Connectivity for SMBs
 Wimax Backhaul
 Nomadic Broadband
 Broadband for Developing Countries
 Private Networks

24. Future of WiMAX !!

25. Questions ??

26.  IEEE802.16-2004
 Alcatel White Paper: WiMAX, making ubiquitous high-
speed data services a reality
 Intel White Paper: Understanding WiMAX and 3G for
Portable/Mobile Broadband Wireless
 WiMAX Forum: www.wimaxforum.com
 http://en.wikipedia.org/wiki/WiMax

27.  BS – Base Station
 SS – Subscriber Station, (i.e., CPE)
 DL – Downlink, i.e. from BS to SS
 UL – Uplink, i.e. from SS to BS
 FDD – Frequency Division Duplex
 TDD – Time Division Duplex
 TDMA – Time Division Multiple Access
 TDM – Time Division Multiplexing
 OFDM – Orthogonal Frequency Division Multiplexing
 OFDMA - Orthogonal Frequency Division Multiple Access
 QoS – Quality of Service

28. THANK YOU