Mobile Audiovisual Terminal: System Design and Subjective Testing in DECT and UMTS networks

It is anticipated that there will shortly be a requirement for multimedia terminals that operate via mobile communications systems. This paper presents a functional specification for such a terminal operating at 32 kb/s in a digital European cordless telecommunications (DECT) and universal mobile telecommunications system (UMTS) radio network. A terminal has been built, based on a PC with digital signal processor (DSP) boards for audio and video coding and decoding. Speech coding is by a phonetically driven code-excited linear prediction (CELP) speech coder and video coding by a block-oriented hybrid discrete cosine transform (DCT) coder. Separate channel coding is provided for the audio and video data. The paper describes the techniques used for audio and video coding, channel coding, and synchronization. Methods of subjective testing in a DECT network and in a UMTS network are also described. These consisted of subjective tests of first impressions of the mobile audio–visual terminal (MAVT) quality, interactive tests, and the completion of an exit questionnaire. The test results showed that the quality of the audio was sufficiently good for comprehension and the video was sufficiently good for following and repeating simple mechanical tasks. However, the quality of the MAVT was not good enough for general use where high-quality audio and video was needed, especially when transmission was in a noisy radio environment

Spectrum Refarming in Sri Lanka: Lessons for Policy Makers and Regulators

The commercial potential of wireless applications has brought spectrum policies to the forefront of regulatory arena. In the context of rapidly increasing demands on spectrum, regulators have to adopt refarming so as to be able to provide spectrum for new services. A variety of models have been chosen by different countries. This paper documents the approach and process adopted by Telecom Regulatory Commission, Sri Lanka (TRCSL) for refarming of spectrum and draws lessons for policy makers and regulators. Sri Lanka was among the early countries in Asia not only to introduce telecom reforms, but also commercial wireless services (mobile and WLL). It may appear that TRCSL’s quick introduction of wireless services gave a head start to Sri Lanka, but the earlier ad-hoc processes led to a situation where spectrum refarming had to be done very quickly subsequently, imposing additional costs on operators and regulators. While realignment was triggered by the need for mobile operators to adopt standard technology, this opportunity could have been strategically used by TRCSL to review spectrum allocations across all the bands, thus allowing faster deployment of digital services. The open consultation process adopted by TRCSL had reduced the risk of “regulatory capture” and it was able to leverage the refarming initiative to bring equity in quantum of spectrum allocated between incumbent and new operators. The study highlights that for rapid proliferation of wireless technologies, a forward looking approach is required not only for managing spectrum but also removal of restrictions on handsets, whose price is a critical aspect for penetration in a developing country context.

Minimum power design of RF front ends

This thesis describes an investigation into the design of RF front ends with minimum power dissipation. The central question is: "What are the fundamental limits for the power dissipation of telecommunication front ends, and what design procedures can be followed that approach these limits and, at the same time, result in practical circuits?" After a discussion of the state of the art in this area, the elementary operations of a front end are identified. For each of these elementary operations, the fundamental limits for the power dissipation are discussed, divided into technology imposed limits and physics imposed limits. A traditional DECT front end design is used to demonstrate the large difference between the fundamental limits and the power dissipation of existing circuits. To improve this situation, first the optimum distribution of specifications across individual subcircuits needs to be determined, such that the requirements for a specific system can be fulfilled. This is achieved through the introduction of formal transforms of the specifications of subcircuits, which correspond with transforms of the subcircuit itself. Using these transforms, the optimum distribution of gain, noise, linearity and power dissipation can be determined. As it turns out, this optimum distribution can even be represented by a simple, analytical expression. This expression predicts that the power dissipation of the DECT front end can be reduced by a factor of 2.7 through an optimum distribution of the specifications. Using these optimum specifications of the subcircuits, the boundaries for further power dissipation reduction can be determined. This is investigated at the system, circuit and technology level. These insights are used in the design of a 2.5GHz wireless local area network, implemented in an optimized technology ("Silicon on Anything"). The power dissipation of the complete receiver is 3.5mW, more than an order of magnitude below other wireless LAN receivers in recent publications. Finally, the combination of this minimum power design method with a platform based development strategy is discussed

DECT-2020 New Radio: The Next Step Towards 5G Massive Machine-Type Communications

Massive machine type communications (mMTC) is one of the cornerstone services that have to be supported by 5G systems. 3GPP has already introduced LTE-M and NB-IoT, often referred to as cellular IoT, in 3GPP Releases 13, 14, and 15 and submitted these technologies as part of 3GPP IMT-2020 (i.e., 5G) technology submission to ITU-R. Even though NB-IoT and LTE-M have shown to satisfy 5G mMTC requirements defined by ITU-R, it is expected that these cellular IoT solutions will not address all aspects of IoT and ongoing digitalization, including the support for direct communication between "things" with flexible deployments, different business models, as well as support for even higher node densities and enhanced coverage. In this paper, we introduce the DECT-2020 standard recently published by ETSI for mMTC communications. We evaluate its performance and compare it to the existing LPWAN solutions showing that it outperforms those in terms of supported density of nodes while still keeping delay and loss guarantees at the required level.Comment: Author-Submitted Paper to IEEE Communications Magazine, 7 pages, 4 figures, 2 table

PCS: regulation and markets

Wireless personal communications technologies are about to enter their second decisive stage of development. Stage one was incremental, supplementing wireline communications networks. Stage two is radical, offering both synergy and substitution, and heralds a third, revolutionary stage in which all that is fixed becomes mobile. Stage two will be one of transition from an environment of limited bandwidths and small but rapidly growing markets, to a world of re-usable and re-assignable spectrum interconnecting with broadband networks for a mass market. Regulating the transition is a controversial process. Spectrum is regarded as a scarce resource which requires careful management in the public interest, yet Hong Kong policy moves in the direction of market solutions. The regulator is therefore required to perform a balancing act between the interests of different parties: the existingwireline and wireless operators, the new entrants, future new entrants, existing customers and future customers, and Hong Kong’s reputation as a progressive free market.published_or_final_versio

Reconfigurable Radio System Test bed for security research

Technological progress on the digital processing has opened the way to a novel implementation approach for wireless communication platforms where most of the digital signal processing is done in software rather than in hardware. Such systems have been known as Software Defined Radio (SDR) or Reconfigurable Radio Systems (RRS). A typical SDR/RRS is able to execute all the radio frequency and base-band processing though software components rather then hardware components as in conventional radio communication systems. This capability provides a high level of reconfigurability and the possibility to implement a number of different algorithms for digital processing. Therefore, SDR/RRS can be used for a variety or purposes including the possibility of implementing wireless security attacks against conventional communication systems. In this technical report, we present an application of the SDR/RRS platform to implement a security attack against a DECT platform. The SDR/RRS platform has been used to implement a DECT demodulator and a processing module to eavesdrop and capture user and control data transmitted by a DECT system. The commercially available Universal Software Radio Peripheral (USRP) has been used as SDR/RRS platform for the development of the prototype. The paper presents the technical challenges and implementation details in the development of the prototype and an overview of the capabilities of the USRP to implement wireless security attacks. The SDR/RRS platform used in the project is quite versatile and it can be used for a number of other applications related to DECT or other wireless communication systems.JRC.G.6-Security technology assessmen