IEEE 802.15.4b is an enhanced standard to the IEEE 802.15.4, addressing the needs for high-data rate transmission using 868 or 915 MHz band in the wireless personal area networks. This paper details a modulation and code mapping scheme designed specifically for the standard's 868 MHz band that leads to efficient transmission and low implementation complexity. The code mapping scheme is called quadrature cyclic odd bit inversion length 16 or quad COBI-16. Among the scheme's desirable properties is that the total phase rotation in the I/Q plane accumulates to O degree over the complete symbol. The scheme is tested in AWGN and Rayleigh fading channels. The results show that it conforms to all the stringent requirements defined by the standard