Adaptive coded modulation is a powerful method for achieving a high spectral efficiency over fading channels. Recently proposed adaptive schemes have employed set-partitioned trelliscoded modulation (TCM) and have adapted the number of uncoded bits on a given symbol based on the corresponding channel estimate. However, these adaptive TCM schemes will not perform well in systems where channel es...

We examine adaptive modulation schemes for at-fading channels where the data rate, transmit power, and instantaneous BER are varied to maximize spectral e ciency, subject to an average power and BER constraint. Both continuous-rate and discrete-rate adaptation are considered, as well as average and instantaneous BER constraints. We nd that for a large class of modulation techniques and fading d...

Spread adaptive quadrature amplitude modulated (AQAM) code-division multiple access (CDMA) is proposed as a powerful means of exploiting the time-variant channel capacity fluctuations of wireless channels. It is studied in comparison to variable spreading factor (VSF)-based techniques. These adaptive-rate transmission methods are compared in the context of joint detection and interference cance...

The Future Wireless Communication requires 100 Mbits/s Data rate, streaming audio/video, asymmetric access/multiple access, Adaptive modulation and coding, dynamic packet arrangement, smart antenna adaptation andIPv6 facility to enhance error free communication. Various digital modulation techniques have been taken for simulation and bit error rate is calculated in both MC-CDMA System and OFDMA...

The vast amount of data needed to represent digital imagery motivates the use of advanced compression systems to reduce the bandwidth required to transmit high-resolution source imagery. We propose two methods to provide optimal image quality at a fixed image delivery rate. The first method, channel-controlled variable-rate (CCVR) image coding, operates within the constraint that the modulation...

In this paper, we propose a hybrid M -ary Quadrature Amplitude Modulation (M -QAM) transmission scheme that jointly uses adaptive modulation and selection combining for singular value decomposition (SVD)-based multiple-input multiple-output (MIMO) systems (AMSC-MIMO). We derive exact closed-form expressions of the performance of the proposed scheme in terms of the average spectral efficiency an...

Cognitive radio is considered as one of the main enablers for provisioning dynamic and flexible spectrum/channel allocation in wireless communications. The reliable data transmission over cognitive radio should employ modulation, coding etc. and thus the performance of such a new communication system should be realized. In this paper, we provide the performance analysis of adaptive modulation o...