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The requirements for future DVB-T/H networks demand that broadcasters design and deploy networks that provide ubiquitous reception in challenging indoors and other obstructed situations. It is essential that such networks are designed cost-effectively and with minimized environmental impact. The EC funded project PLUTO has since its start in 2006 explored the use of diversity to improve coverage in these difficult situations. The purpose of this paper is to investigate the performance of Transmit Delay Diversity (DD) with two antennas to improve the reception of DVB-T/H systems operating in different realistic propagation conditions through a series of tests using a SPIRENT SR5500 dual channel emulator. The relationship between correlation coefficient between channels, receiver velocity and diversity gain is investigated. It is shown that transmit delay diversity significantly improves the quality of reception particularly in simulated fast fading mobile broadcasting applications. This paper documents research conducted by Brunel University and Broadreach Systems. Index Terms--Doppler frequency, DVB-T/H, errored second ratio (ESR), MIMO, spatial correlation, transmit delay diversity (DD).

Audio networking is a growing field, introducing new and exiting possibilities in the professional audio industry [1]; but it also drastically changes the way audio systems will be designed, built, and used. Today's networks have enough bandwidth to transport hundreds of high quality audio channels, replacing hundreds of kilograms of cabling in conventional analog audio systems [2]. Currently there are many systems on the market that distribute audio over Ethernet but the majority of sound engineers are not using them yet. There are mainly two reasons that audio networks are not as popular as expected. First, many of the systems are based on a proprietary implementation that does not allow interoperability between different vendors. Second, wired networks, like the conventional analog audio networks, also need a cable installation. It is therefore understood that the development of a wireless digital audio distribution system would be a significant contribution in this sector. IEEE 802.11 (Wi-Fi) as the primary wireless technology in computer networking has made wireless networks widely available and inexpensive. With its most recent amendments, as well as the use of the 5-GHz ISM band, it can facilitate many high quality audio channels. However, the use of this technology has not been the choice for the audio industry so far. It is obvious that a sequence of problems related with the nature of this technology impede the use of Wi-Fi in professional live sound and studio applications [3]. Apart from the well-known drawbacks of interference and security, encountered in all wireless data transmission systems, the way that Wi-Fi arbitrates the wireless channel access is what causes the majority of the problems. In this paper we highlight the drawbacks of the IEEE 802.11 MAC algorithm in handling multiple stations broadcasting of audio data. We simulate a live audio data wireless network and test the limits of the protocol for this type of traffic. Moreover, we modify the 802.11 MAC algorithm to address the above problems. We test the amended protocol using simulation and analyze the results. We also give the directions for the future research in order for this widely accepted technology to be used in the professional audio industry. [ABSTRACT FROM AUTHOR]