in this paper the problem of minimizing the total transmitting power subject to a fixedtotal bit rate in ofdm systems is considered. upper bounds on transmitting power and bit rate ofeach subcarrier can also be taken into account. in practice, the number of bits of each subcarriershould be integer and nonnegative. in this paper an analytical optimal solution is derived for thecase of assuming t...

This paper examines the performance of bundled ADSL systems and proposes an extension to their bit-loading mechanism that results to fair allocation of the available bandwidth. The “ratemaximization” bit-loading method provides less average data rate compared to the optimum “target-rate” strategy, which depends on the number of active lines in the system and the length of the DSL loop. Under a ...

This paper considers discrete multitone (DMT) modulation for multiuser communications where different users are supported by the same system. These users may have differing quality of service (QoS) requirements, as quantified by their respective bit rate and symbol error rate specifications. Our goal is to minimize the transmitted power given the QoS specifications for the different users, subj...

This paper addresses the topic of bit and power loading in coded MIMO-OFDM systems. Due to the need of designing communication systems with high spectral efficiencies, the combination of multiple antennas at transmitter and receiver with OFDM represents a promising approach. Moreover, channel knowledge at the transmitter can be exploited to adapt the transmission to the channel. While loading s...

Abstract– We present adaptive power and bit loading schemes for a bit-interleaved coded OFDM system with perfect channel state information and square quadrature amplitude modulation constellations. In order to minimize the bit error rates at the output of the Viterbi decoder subject to bit rate and power constraints, an analytical expression for the bit-error rate (BER) of a harddecision device...

In this paper we compare cyclic prefix (CP) based single and multicarrier block transmission schemes in frequencyselective fading channels. Analytical comparison shows that at moderate-to-high signal-to-noise ratio (SNR), the uncoded error rate performance of multicarrier transmission is inferior to that of single carrier. We propose new minimum bit error rate (MBER) power loading algorithms fo...

This study is designed to consider the two important yet often neglected factors, which are factory recommendation and bit features, in optimum bit selection. Image processing techniques have been used to consider the bit features. A mathematical equation, which is derived from a neural network model, is used for drill bit selection to obtain the bit’s maximum penetration rate that corresponds ...