OFDM is a multicarrier modulation technology which has efficient spectrum utilization to support the transmission of high data rates. The typical subcarrier modulation schemes used in orthogonal frequency division multiplexing (OFDM) system includes: b inary phase shift keying (BPSK), phase shift keying (PSK) and quadrature amplitude modulation (QAM). This paper analyses the comparative perform...

In this paper, using the exact expression for the pairwise error probability derived in terms of the message symbol distance between two message vectors rather than the codeword symbol distance between two transmitted codeword matrices, the exact closed form expressions for the symbol error probability of any linear orthogonal space-time block codes in slow Rayleigh fading channel are derived f...

To investigate short-distance, point-to-point, infrared channels, a test-bench and circuits were constructed to determine the limitations of existing optoelectronics. The results of these measurements are used to formulate a channel model which is employed for the subsequent analysis of candidate bandwidth efficient modulation schemes. A new multilevel modulation scheme,Adaptively Biased QAM (A...

In this paper,we present new constructions for M -QAM and 2M Q-PAM Golay complementary sequences of length 2 for integer n, where M = 2 for integer m. New decision conditions are proposed to judge whether the sequences with offset pairs proposed by Ying Li are Golay complementary, and with the new decision conditions, we prove the conjecture 1 and point out some drawbacks in conjecture 2 propos...

We study the performance of constant-power variable-rate M-QAM schemes over Nakagami fading channels. We obtain closed-form expressions for the outage probability, spectral eeciency and average bit-error-rate (BER) assuming perfect channel estimation and negligible time delay. For a target BER of 10 ?3 , the spectral eeciency of adaptive continuous rate M-QAM comes within 5 dB of the Shannon ca...

IEEE specifies different modulation techniques for WiMAX; namely, BPSK, QPSK, 16 QAM and 64 QAM. This paper studies the performance of Internet Protocol Television (IPTV) over Fixed WiMAX system considering different combinations of digital modulation. The performance is studied taking into account a number of key system parameters which include the variation in the video coding, path-loss, sch...

The author considers the use of coding to reduce the peak-to-mean envelope power ratio (PMEPR) for orthogonal frequency division multiplexing (OFDM) systems. Most of the existing schemes that use coding for PMEPR reduction assume a PSK constellation. The author presents the construction of non-square M-QAM symbols from a combination of QPSK and BPSK signals when M=2 and n is an odd number. By u...

The RF sections of Analog FM and Digital Radios primarily differ in the required linearity. If the transmitter amplifiers and attendant switching functions are not extremely linear, AM to AM and AM to PM conversion can cause serious deterioration of Bit Error Rate (BER) and an increase in intersymbol interference (ISI). Higher order QAM Systems such as 64-QAM and 256-QAM require even higher lev...

We propose a novel 16-quadrature amplitude modulation (QAM) transmitter based on two cascaded IQ modulators driven by four separate binary electrical signals. The proposed 16-QAM transmitter features scalable configuration and stable performance with simple bias-control. Generation of 16-QAM signals at 40 Gbaud is experimentally demonstrated for the first time and visualized with a high speed c...