Markku Niemi

Tutorial: Trends in personal wireless data communications

This paper gives an overview of the background, current status, and ongoing trends in wireless personal data communications. The driving force behind the future development is proven to be the convergence of multimedia content, the Internet, and wireless mobile devices. Network technologies from global coverage to short-range personal area networks are reviewed focusing on the most prospective standardisation and specification efforts. Future wireless services will be implemented using several network technologies, due to which the portability of services across networks is the most important issue. Especially the support for Quality of Service is emphasised in each wireless network. In a discussion, winners and losers are examined from the global convergence point of view.

Video transfer control protocol for a wireless video demonstrator

Real-time streaming video is expected to emerge as a key service in different telecommunications systems, including wireless networks. This paper presents the functionality and implementation of the wireless Video Control Protocol (VCP). The protocol has been implemented for developing the functionality for real-time video stream transmission over heterogeneous wireless network technologies. VCP is embedded into a wireless video demonstrator. The demonstrator consists of Windows NT hosts containing a real-time H.263 encoder, video stream parsing functionality, and several network connections, such as wireless LAN, Bluetooth and GSM data. The protocol contains functionality for protecting the video stream transfer and adapting different network technologies together.

Implementation of wireless LAN access point with quality of service support

The maintaining of the quality of service (QoS) of the data transfers in wireless local area networks (WLAN) is an extensive task. An implementation of an access point (AP) providing an access from WLANs to backbone wired networks is presented in this paper. The AP adapts the QoS signalling of the connected networks. The AP has been implemented in Windows NT workstation as a protocol driver and its operation has been verified. The evaluation of the driver performance encourages the usage of the AP in demanding environments.

Architecture of a wireless video transfer demonstrator

This paper presents the architecture of a wireless video transfer demonstrator. The demonstrator has been implemented for developing control protocols and QoS support for real-time video streaming services. The demonstrator contains modules for video capture, encoding, stream protection and transfer for wireless link or network, as well as for decoding and displaying at the receiver. H.263 encoding is performed in real-time using dedicated hardware. A video control protocol has been designed and implemented for managing the stream transfer and for collecting measurement information. The current implementation operates over wireless LAN, GSM data, Bluetooth and a proprietary wireless LAN called TUTWLAN. In addition, a special module has been implemented for simulating different wireless links or networks locally.

Performance evaluation of Secure Remote Password protocol

The paper evaluates the performances of the Secure Remote Password (SRP) authentication protocol computations. The software implementations are written in C with the MIRACL and OpenSSL libraries utilized and evaluated on Pentium III and ARM9TDMI microprocessors. Accelerating the performance of the critical computational parts with dedicated hardware is discussed. The measurements show that with a prime modulus of length 2048 bits the SRP computations take 80.5 ms on 700 MHz Pentium III and 503 ms on 200 MHz ARM9TDMI with the highest software optimizations within the libraries. With maximal precomputation the execution times can be decreased down to 30.6 ms and 194 ms respectively. By adding appropriate hardware support for the SHA-1 hash computation and exponentiation their cycle counts can be reduced at least by factors of 10 and 20.

A system scenario for wireless broadband access with multimedia support

Radio access networks are evolving towards the support for mobile multimedia services with quality of service (QoS) guarantees. While this trend is clearly seen, a relation to the fixed network evolution and the legacy wireless systems has to be kept in mind. This paper discusses a general reference scenario for broadband radio access networks with QoS support. In this context the required entities, distribution of functionalities and interfaces are studied in detail using ATM core network and wireless ATM radio access network as example technologies. Finally, an ATM based system demonstrator is discussed.

Wireless ATM - Multimedia Service Platform

The need to provide multimedia services in the wireless environment has increased remarkably. This is being driven by the rapid service development in the computer environment as well as by the increasing penetration of wireless communication systems. In this paper we describe the development of wireless multimedia services and their requirements. A gradual introduction of multimedia capabilities to the users is discussed. For each phase of this process a corresponding wireless system is identified. Finally, Wireless ATM is presented as a potential technology to be able to provide enough bandwidth along with a good Quality of Service (QoS) support for new multimedia services in a wireless environment.