802.11b PHY Matlab™ Model

802.11b PHY Matlab™ Model is a floating-point implementation of IEEE Standard 802.11b 1999 Edition in Matlab™. The IEEE 802.11b specification is the high rate extension of the Physical Layer for the Direct Sequence Spread Spectrum (DSSS) system (as per IEEE Standard 802.11 - 1999) for the 2.4 GHz band designated for ISM applications.

This extension of the DSSS system builds on the data rate capabilities of 802.11 to provide 5.5 and 11 Mbps payload data rates in addition to the 1 and 2 Mbps rates. To provide the higher rates, 8 chip Complementary Code Keying (CCK) is employed as the modulation scheme with the chipping rate of 11 MHz thus providing the same occupied channel bandwidth.

In addition to providing higher speed extensions to the DSSS system, a number of optional features are described that will allow the performance of the Wireless LAN system to be improved.

An optional mode replacing the CCK modulation with Packet Binary Convolutional Coding (PBCC) is provided. Another optional mode, which allows data throughput at the higher rates (2, 5.5 and 11 Mbps) to be significantly increased by using a shorter PLCP preamble is also provided.

Technical Specification

• Supports all data rates and modulation schemes:1, 2, 5.5 (CCK/PBCC), 11 (CCK/PBCC) Mbps
• Short and Long Preamble
• Coherent and Non-coherent demodulation
• Framed (using 802.11b framing) and Unframed (modulation only) Modes
• Exhaustive set of channel models: AWGN, 802.11 exponential channel, HiPERLAN/2 A, B, C, D, E channels, JTC, and user defined Rayleigh and Rician fading channels with Doppler effects
• Transmit Filter to meet standard transmit spectral mask characteristics
• Channel Impulse Response (CIR) Estimation with Rake Receiver and DFE Equalization
• Support for all synchronization non-idealities estimation, correction and tracking: Symbol acquisition, Carrier frequency offset, Sampling clock frequency Offset, and Timing jitter
• Fast Viterbi Decoder implementation for PBCC mode as Matlab™ C-Mex code.
• Support for both Hard/Soft Viterbi Decoder in PBCC mode
• Support for modeling several RF/Analog Front End non-idealities: Power Amplifier non-linearity, I/Q Imbalance, Phase Noise, A/D and D/A quantization and dynamic range
• Support for analyzing system performance: BER, PER, Transmitter Spectrum, Receiver Constellation, Channel / Synchronization/ Front end impairments, and implementation loss
• Advanced Graphical User Interface including support for on-line performance plots (like PER Vs. SNR, PER Vs. Delay Spread, etc), multiple simulations, and merging results from several simulations
• Several input data formats (text, image, audio/video) and internal random data and AWGN generation
• Support for Bluetooth interference modeling
• On-line help files
• High simulation throughput of over 5 Kbps and low memory requirements
• Full source availability

Applications

• IEEE 802.11b System Understanding
• IEEE 802.11b System Performance / Implementation Loss Analysis
• Custom Algorithm Implementation and Evaluation
• Basis for IEEE 802.11b System Realization

Platforms

• Available on Matlab™ 6.1 and GNU Octave 2.1
• For Fixed Point 802.11b PHY Matlab™ / C Model contact mkt@ittiam.com