Joint compensation of IQ-imbalance and carrier phase sychronization errors in communication receivers

This work addresses the joint compensation of IQimbalances and carrier phase synchronization errors of zero- IF receivers. The compensation scheme based on blind-source separation which provides simple yet potent means to jointly compensate for these errors independent of modulation format and constellation size used. The low-complexity of the algorithm makes it a suitable option for real-time deployment as well as practical for integration into monolithic receiver designs.

Living and dealing with RF impairments in communication transceivers

This paper provides an overview of the sources and effects of the RF impairments limiting and rendering the performance of the future wireless communication transceivers costly as well as hindering their wide-spread use in commercial products. As transmission bandwidths and carrier frequencies increase effect of these impairments worsen. This paper studies and presents analytical evaluations of the performance degradation due to the RF impairments in terms of bit-error-rate and image rejection ratio. The paper also give highlights of the various aspects of the research carried out in mitigating the effects of these impairments primarily in the digital signal processing domain at the baseband as well as providing low-complexity hardware implementations of such algorithms incorporating a number of power and area saving techniques.

The Use of Almost Linear Phase IIR filters In DFT Modulated Filter Banks for Communication Systems

This paper is on the use and performance of M-path polyphase Infinite Impulse Response (IIR) filters for channelisation, conventionally where Finite Impulse Response (FIR) filters are preferred. This paper specifically focuses on the Discrete Fourier Transform (DFT) modulated filter banks, which are known to be an efficient choice for channelisation in communication systems. In this paper, the low-pass prototype filter for the DFT filter bank has been implemented using an M-path polyphase IIR filter and we show that the spikes present at the stopband can be avoided by making use of the guardbands between narrowband channels. It will be shown that the channelisation performance will not be affected when polyphase IIR filters are employed instead of their counterparts derived from FIR prototype filters. Detailed complexity and performance analysis of the proposed use will be given in this article.

Welcoming International Visitors - Communication and Culture

It is extremely rare for an international visitor to museums and galleries in the UK to find information in foreign languages which is anything more than a relatively literal translation of an English source text. At the same time, a huge body of research and theory in the humanities and social sciences implies that major cultural differences are likely to accompany the differences in first language of international visitors. As such, in spite of the fact that museums and galleries often declare their intention to meet the needs of their visitors, it is fairly clear that, in this instance, they are at best meeting their international visitors’ linguistic needs whilst ignoring their broader cultural needs. With this in mind, staff from the University of Westminster together with a number of London’s major museums and galleries obtained UK Research Council funding to work on the production of leaflets in foreign languages fully acknowledging cultural differences amongst international visitors. The collaboration was intended to generate reflection on how such materials might be most effectively produced, what impact they might have and what forms of policy review museums and galleries might as a result wish to undertake. The collaboration confirmed that cultural difference, and therefore difference in need, between visitors with different first languages is a simple reality. Translations, including ones which are culturally ‘adapted’ or ‘sensitive’, will always fall short of acknowledging the intercultural complexity of the experience of international visitors. Materials acknowledging that complexity are more effective. Museums and galleries need, therefore, to ask themselves how far and in what ways they wish to acknowledge this reality in the nature of the welcome they offer. The core of this article will draw on the outcomes of this collaboration, and also on aspects of translation and intercultural theory, to offer a critical exploration of some of the options museums and galleries therefore have in producing materials to welcome international visitors in ways which acknowledge the intercultural complexity of their experience.