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In the ubiquitous personal area network based on MB-OFDM, huge amount of multimedia data and software components will be transmitted, and this huge data will require higher data rate, and reliability over various wireless channel. Therefore, in this paper, dynamic signal transmission with intelligent transmission scheme for MB-OFDM system is considered. The intelligent transmission technique is investigated for the most suitable adaptation in various channel environments. For this scheme, the proposed technique includes STBC, BLAST, and STBC-BLAST in all. By properly selecting their MIMO schemes using estimated SNR, the proposed technique has the advantage of each technique; diversity gain or high transmission rate relative to general scheme. [ABSTRACT FROM AUTHOR]

A combination of OFDM with FDMA called OFDMA is regarded as a promising solution for improving the performance of BWA with multiple users. Although transmit diversity is clearly advantageous on OFDMA systems, it may not be possible that practical OFDMA systems have more than two antennas due to size, cost, or hardware limitations. Cooperative networks aim to utilize the available terminals as a collection of distributed antennas for the transmission of signals from one end of the network to the other. This paper focuses on design and performance evaluation of IEEE 802-13 MIMO-OFDMA systems with cooperative diversity. In this paper, for high rate and reliable transmission, efficient transmission codes are proposed for each transmission case (single transmission case or mutual transmission case). [ABSTRACT FROM AUTHOR]

The diversity techniques -- space time block code (STBC), maximum ratio combining (MRC) -- with multiple antennas provide better reliability than general system. But there are some limitations such as size, cost, hardware complexity, etc, because of multiple antennas. In this paper, we propose a novel relaying transmission technique using STBC. We can overcome those limitations and give the gain of relaying transmission diversity in a concept of virtual multi-input multi-output (MIMO) with single transmit antenna. And orthogonal frequency division multiple access (OFDMA) uplink technology which is considered as an answer for digital video broadcasting -- return channel terrestrial (DVB-RCT) system is used to evaluate the performances of proposed technique. [ABSTRACT FROM AUTHOR]

The enormous amount of multimedia data will be transmitted by various devices of the wireless personal area network, and this network environment will require very high transmission capacity. In this paper, we apply multiple antenna to MB-OFDM UWB system for high performance. With an emphasis on a preamble design for multi-channel separation, we address a channel estimation in MB-OFDM system with multiple antenna. By properly designing each preamble for multiple antenna to be orthogonal in time domain, the channel estimation can be applied to the MB-OFDM proposal for IEEE 802.15.3a standard in the case of more than 2 transmit antennas. By using the multiple antenna scheme and proposed channel estimation technique, the reliability and performance of MB-OFDM system can be improved. [ABSTRACT FROM AUTHOR]

As with the transmitter and transmission line, the antenna and its performance characteristics play an important role with regard to digital television system performance. Together with AERP, the shape and orientation of the antenna pattern determines a station's coverage. The shape of the antenna pattern determines the directivity, which with the transmission line and antenna efficiency, determines the transmitter output power required to achieve the AERP. Antenna power rating must be consistent with these requirements. The antenna wind load contributes significantly to tower loading and cost. Antenna impedance, pattern bandwidth, and associated frequency response are important components of overall system response. Other antenna characteristics affecting system performance include tower mounting and channel combining strategies. These factors are examined in detail in this chapter. [ABSTRACT FROM PUBLISHER]

Modulation is the means by which a user signal or message is prepared for carriage by radio. Audio and broadcast radio systems use 'amplitude modulation (AM)' and 'frequency modulation (FM)'. Modern digital radio systems, on the other hand, use encoding techniques as modulation schemes. These include 'on-off keying (OOK)', 'frequency shift keying (FSK)' and 'quadrature amplitude modulation (QAM)'. Modulation at the transmitting end of a radio link and demodulation at the receiving end is carried out by the radio 'modem' (modulater/demodulater). This chapter discusses these terms in detail. [ABSTRACT FROM PUBLISHER]

An encyclopedia entry for "Multiple Input, Single Output" is presented. Multiple Input Single Output (MISO) refers to a smart antenna technology that uses multiple transmitters and a single receiver on a wireless device to enhance transmission distance. MISO implementation includes multiple antennas at the source and at the destination.