WiMAX Air Interface

3 days

Download brochureThe course focuses on the mobile WiMAX (IEEE 802.16e) air interface and explains in great detail all its functions and processing blocks. It contains logically structured topics covering mobile WiMAX architecture, key techniques used in WiMAX such as OFDM, OFDMA and MIMO, WiMAX PHY and MAC layer processing and all the important radio interface procedures. Special attention is given to the WiMAX PHY layer, where the architecture of the radio frames (both TDD and FDD) is examined with all the corresponding channels, resource mapping options and procedures. A thorough overview of MAC protocol is given due to its complexity and importance in the WiMAX operation.

The course utilizes a number of hands-on practical exercises using the state-of-the art WiMAX PHY Lab  – a Link Level Simulator applied to observe signals, channels and frames of the WiMAX air interface.

Introduction to WiMAX

• WiMAX network architecture
• Nodes and domains: MS, BS, ASN-GW, ASN, CSN
• Interfaces: R1, R8, R6, R4, R3, R2
• ASN Profiles
• WiMAX bandwidths and bit rates
• Summary of radio access techniques used in WiMAX air interface

Overview of OFDM and OFDMA

• Fundamentals of multipath propagation (selectivity in time, frequency and space)
• Basics of OFDM transmission, subcarriers, cyclic prefix, IFFT/FFT processing
• OFDMA as an extension of OFDM
• Multiple access with OFDMA
• Advantages and disadvantages of OFDM and OFDMA

WiMAX Air Interface Protocol Structure

• WiMAX air interface protocol stack
• Control information and user data organization
• Information mapping: bursts, sub-channels and slots

WiMAX PHY Layer

• RF channel definitions
• MS and BS transmitter power parameters
• PHY interface options: WirelessMAN-SC, WirelessMAN-SCa, WirelessMAN-OFDM, WirelessMAN-OFDMA, WirelessHUMAN
• OFDMA parameters for WirelessMAN-OFDMA
• TDD and FDD radio frame organizations
• Radio frame elements (sub-frames, sub-channels, slots, data regions, bursts, TTG, RTG)
• Channels and signals (preambles, DL-MAP, UL-MAP, DCD, UCD, FCH, Ranging, fast feedback channel)
• Subcarrier allocation schemes and pilot assignment
• Pseudo random permutations: FUSC, PUSC and Optional PUSC
• Adaptive permutation: Adaptive Modulation and Coding (AMC)
• MIMO scenarios in WiMAX for downlink and uplink
• Adaptive MIMO switch
• Space-Time Coding and Spatial Multiplexing
• Beamforming
• Uplink Collaborative MIMO
• MIMO allocations in the frame
• Downlink and uplink processing chain including channel coding, modulation, subcarrier mapping, Space-Time Coding and OFDMA signal generation

WiMAX PHY Layer Demo and Experiments (tool-based)

• OFDMA waveforms
• Chosen BS and MS signals and PHY channels shown in the time and frequency domain
• Complete downlink and uplink radio frame shown as time-frequency grid

WiMAX MAC Layer

• MAC overall architecture and functions
• MAC sub-layers: Security, Common Part, Convergence
• Logical connections, service flows and QoS
• Link adaptation mechanism, Adaptive Modulation and Coding
• MAC security processing
• Power saving
• MAC packet processing
• Hybrid ARQ
• Timing Relationship and Timing Advance

WiMAX Radio Interface Procedures

• Synchronization
• Cell selection, reselection
• System info acquisition
• Ranging procedure and allocations
• Initial and periodic ranging
• Handover ranging
• Bandwidth request
• Power control for uplink and downlink, closed loop and open loop
• Measurements and reporting
• RSSI, CINR, relative delay, round trip delay
• WiMAX reporting events

WiMAX Deployment

• Planning for coverage and capacity
• Site sharing options
• Tools used in the planning process
• Self-organizing networks (SON) concept