TY - JOUR
T1 - Adaptive modulation scheme for simultaneous voice and data transmission over fading channels
AU - Alouini, Mohamed Slim
AU - Tang, Xiaoyi
AU - Goldsmith, Andrea J.
N1 - Funding Information:
Manuscript received January 1997; revised January 1999. The work of M.-S. Alouini was supported in part by a National Semiconductor Graduate Fellowship Award and in part by the Office of Naval Research under Grant NAV-5X-N149510861. The work of X. Tang was supported by a Summer Undergraduate Fellowship (SURF) award. This is an expanded version of work which was presented at the IEEE Vehicular Technology Conference (VTC’98), Ottawa, Ont., Canada, May 1998.
PY - 1999/5
Y1 - 1999/5
N2 - We propose a new adaptive modulation technique for simultaneous voice and data transmission over fading channels and study its performance. The proposed scheme takes advantage of the time-varying nature of fading to dynamically allocate the transmitted power between the inphase (I) and quadrature (Q) channels. It uses fixed-rate binary phase shift keying (BPSK) modulation on the Q channel for voice, and variable-rate M-ary amplitude modulation (M-AM) on the I channel for data. For favorable channel conditions, most of the power is allocated to high rate data transmission on the I channel. The remaining power is used to support the variable-power voice transmission on the Q channel. As the channel degrades, the modulation gradually reduces its data throughput and reallocates most of its available power to ensure a continuous and satisfactory voice transmission. The scheme is intended to provide a high average spectral efficiency for data communications while meeting the stringent delay requirements imposed by voice. We present closed-form expressions as well as numerical and simulation results for the outage probability, average allocated power, achievable spectral efficiency, and average bit error rate (BER) for both voice and data transmission over Nakagami-m fading channels. We also discuss the features and advantages of the proposed scheme. For example, in Rayleigh fading with an average signal-to-noise ratio (SNR) of 20 dB, our scheme is able to transmit about 2 Bits/s/Hz of data at an average BER of 10-5 while sending about 1 Bit/s/Hz of voice at an average BER of 10-2.
AB - We propose a new adaptive modulation technique for simultaneous voice and data transmission over fading channels and study its performance. The proposed scheme takes advantage of the time-varying nature of fading to dynamically allocate the transmitted power between the inphase (I) and quadrature (Q) channels. It uses fixed-rate binary phase shift keying (BPSK) modulation on the Q channel for voice, and variable-rate M-ary amplitude modulation (M-AM) on the I channel for data. For favorable channel conditions, most of the power is allocated to high rate data transmission on the I channel. The remaining power is used to support the variable-power voice transmission on the Q channel. As the channel degrades, the modulation gradually reduces its data throughput and reallocates most of its available power to ensure a continuous and satisfactory voice transmission. The scheme is intended to provide a high average spectral efficiency for data communications while meeting the stringent delay requirements imposed by voice. We present closed-form expressions as well as numerical and simulation results for the outage probability, average allocated power, achievable spectral efficiency, and average bit error rate (BER) for both voice and data transmission over Nakagami-m fading channels. We also discuss the features and advantages of the proposed scheme. For example, in Rayleigh fading with an average signal-to-noise ratio (SNR) of 20 dB, our scheme is able to transmit about 2 Bits/s/Hz of data at an average BER of 10-5 while sending about 1 Bit/s/Hz of voice at an average BER of 10-2.
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U2 - 10.1109/49.768199
DO - 10.1109/49.768199
M3 - Article
AN - SCOPUS:0032627774
SN - 0733-8716
VL - 17
SP - 837
EP - 850
JO - IEEE Journal on Selected Areas in Communications
JF - IEEE Journal on Selected Areas in Communications
IS - 5
ER -