Enhancing MB-OFDM throughput with dual circular 32-QAM

Abstract

Quadrature Phase Shift Keying (QPSK) and Dual Carrier Modulation (DCM) are currently used as the modulation schemes for Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) in the ECMA-368 defined Ultra-Wideband (UWB) radio platform. ECMA-368 has been chosen as the physical radio platform for many systems including Wireless USB (W-USB), Bluetooth 3.0 and Wireless HDMI; hence ECMA-368 is an important issue to consumer electronics and the user's experience of these products. To enable the transport of high-rate USB, ECMA-368 offers up to 480 Mb/s instantaneous bit rate to the Medium Access Control (MAC) layer, but depending on radio channel conditions dropped packets unfortunately result in a lower throughput. This paper presents an alternative high data rate modulation scheme that fits within the configuration of the current standard increasing system throughput by achieving 600 Mb/s (reliable to 3.1 meters) thus maintaining the high rate USB throughput even with a moderate level of dropped packets. The modulation system is termed Dual Circular 32-QAM (DC 32-QAM). The system performance for DC 32-QAM modulation is presented and compared with 16-QAM and DCM 1 .

Inter-carrier Interference Reduction Scheme for SFBC-OFDM Systems

“…The main idea of this method is to map one data symbol onto a group of subcarriers by considering the predefined ICI weighting function. We note that the idea of mapping one data symbol onto a group of subcarriers has also been used in multiband OFDM systems to obtain frequency diversity gain [19]- [20]. We note that the idea of mapping one data symbol onto a group of subcarriers has also been used in multiband OFDM systems to obtain frequency diversity gain [19]- [20].…”

“…By doing so, ICI signals generated within a group can self-cancel each other via a simple method [13]- [15]. We note that the idea of mapping one data symbol onto a group of subcarriers has also been used in multiband OFDM systems to obtain frequency diversity gain [19]- [20]. This notion is the underlying essence of the dual carrier modulation (DCM) scheme.…”

Improvement in SNR with digital coding technique in OFDM transmission system

“…For this purpose the modulation technique and FFT/IFFT [8] are the main building blocks of OFDM. In our approach 32-QAM [9] and 128 point IFFT/FFT are used. But before describing those we are explaining some basic blocks of OFDM.…”

Design of a Labeling Scheme for 32-QAM Delayed Bit-Interleaved Coded Modulation

“…In this work, we attempt to tackle this problem. We consider the cross 32-QAM constellation for its wide application in practical systems and its high energy efficiency [ 25 , 26 , 27 , 28 ]. To design the labeling scheme for 32-QAM DBICM in order to maximize the DBICM capacity, a straightforward way is to enumerate all the 32-QAM labeling schemes for each number of delayed bits.…”