O'Reilly logo

Home Network Basis: Transmission Environments and Wired/Wireless Protocols by Walter Y. Chen

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

10.5. Orthogonal Frequency Division Multiplexing

A 64-point complex number IFFT/FFT operation forms the modulation mechanism for this 802.11a wireless Ethernet. Among 64 subcarriers, 48 of them are used for BPSK, QPSK, 16) Quadrature Amplitude Modulation (QAM), or 64QAM, 4 of them are used for pilot tone. Complex time domain signals are modulated onto in-phase and quadrature channels of an RF carrier separately. A rate 1/2 convolution code is used for error protection. Rate 2/3 and 3/4 codes are derived through puncturing. An interleaving process is used to randomize subcarrier and bit location distribution among each OFDM symbol.

10.5.1. Summary of 802.11a Standards

The packet format for the OFDM implementation of wireless Ethernet at 5 GHz ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required