Handover Mechanism in IEEE 802.16e, WiBro

by

Bhupendra Borse

WiBro Network Architecture

WiBro Specifications:

• Operating Frequency 2.4 GHz

• 9 MHz Bandwidth

• Mobility up to 60 km/hr (31 miles/hr)

Physical Layer

• R = N * b * c / T

Where:

N = Number of used sub carriers

b = Number of bits per modulation symbol

c = Coding rate

T = OFDM symbol duration

Calculation at Physical Layer• Fs = floor (Sampling-factor * Channel-Bandwidth / 8000) * 8000Where: Sampling-Factor = Sampling Factor. This is set to 8/7 in the implementation. Channel-Bandwidth = Channel bandwidth, in Hz• symbol time, Tb, is calculated by using the following formula: Tb = FFT-size / FsWhere: FFT-size = FFT size • Cyclic prefix time, Tg = G * Tb Where:

G = Ratio of cyclic prefix time to useful symbol time. The following values are supported in the implementation: 1/32, 1/16, 1/8, and 1/4.

Tb = Useful symbol time• OFDMA symbol time, T, is calculated by using the following formula: T = Tb + TgWhere: Tb = Useful symbol time Tg = Cycle prefix time

Types of Handover

• BS initiated HO

• MS initiated HO

BS Base Station

MS Mobile Station

BS initiated HO

MS initiated HO

Scenario 1: Two Cell Two HO

Handover shown

Analysis : MAC Layer

Analysis : Application Layer

VBR Client VBR Server

Scenario : Two HO using VBR application

Analysis: Application Layer

VBR clients VBR server

Future Work

• Handovers taking place with background Traffic and Faults

• Handovers taking while running VoiP application

• If Possible, Handovers under weather effect

References • F. Wang et al, “IEEE 802.16e System Performance: Analysis and

Simulations”, Presented at PIMRC Conference, 2005.• R. Koodli, ”Fast Handover for Mobile IPv6,” Internet Draft,” MobileIP Working Group, 2004• K. El Malki, ”Low Latency Handoffs in Mobile IPv4,”, Internet Draft,” Network Working Group, 2004 • IEEE P802.16e/D4, ”Draft IEEE Standard for Local and Metropolitan Area

Networks—Part 16: Air Interface for Fixed and Mobile Broadband Wireless Access Systems,” Aug, 2004• “Design and Implementation of a Simulator Based on a Cross-Layer

Protocol between MAC and PHY Layers in a WiBro Compatible IEEE 802.16e OFDMA System",Taesoo Kwon, Howon Lee, Sik Choi, Juyeop Kim, and Dong-Ho Cho,Korea Advanced Institute of Science and Technology Sunghyun Cho, Sangboh Yun, Won-Hyoung Park, and Kiho Kim, Samsung Advanced Institute of Technology. 0163-6804/05/@© 2005 IEEE Communications Magazine • December 2005