CCK Modulation: Beyond Wi-Fi

The full-rate IEEE 802.11b standard for wireless local area networks, also known as Wi-Fi, employs 256-ary complementary code keying (CCK). For applications that do not require adherence to the standard, it may be desirable to use forward error correction coding with CCK, but the bit-to-symbol mappings used in IEEE 802.11b degrade the performance of most standard binary codes. We show that a standard binary convolutional code performs much better with alternative bit mappings, and we demonstrate that chip scrambling gives additional improvement.