Integrated voice and data transmission employing adaptive modulation in wireless networks

In this paper, we propose an integrated voice and data transmission technique using adaptive modulation, wherein the effective data transmission rate (throughput) is improved by allowing the bit-error rate (BER) for voice to increase beyond the BER needed for data. In a given integrated frame with data and voice bits, voice bits are allowed to use higher-order modulation as compared to data bits due to the higher tolerance of voice to BER. This leads to a larger symbol duration for voice which is subsequently shrunk into fewer bits, provided the resulting increase in voice BER does not exceed its maximum acceptable limit. This shrinking operation releases some bits from the voice quota, which are eventually utilized for data transmission in addition to the predefined data bits in the same frame. In this work, we first examine the feasibility of the proposed scheme for a time-invariant AWGN channel. Subsequently, we use our methodology in an adaptive manner for fading channels. We also examine the performance of the proposed scheme for a Global System for Mobile communication (GSM) system. Using the proposed scheme, our analysis indicates that one can dynamically enhance the overall throughput significantly in a broadband wireless network.