Parc des Algorithmes, Saint-Aubin,

2 Requirements and constraints for short range wireless networks deployment.................9 2.1 User deployment scenarios and potential application space of WLAN/WPAN/WBAN/WSN technologies.................................................................................

Modulated Filter Banks with Minimum Output Distortion in Presence of Subband Quantization

This paper presents modulated minimum mean squared error (MMSE) filter banks, designed for subband coding purposes. Uniform scalar quantizers, the synthesis prototype and an additional gain control factor per subband are optimized in a rate-distortion sense. The main advantage of the proposed solution is to keep the efficient modulated implementation of the synthesis filter bank, while reducing the reconstruction distortion introduced by quantization of the subband signals. It is shown that, in many circumstances, the resulting schemes are almost as efficient as plain MMSE filter banks (Wiener filters with optimized quantizers). 1. Introduction Classically, in filter bank (FB) based coding schemes, the signal to be encoded is split into several decorrelated subband components prior to quantization. The analysis and synthesis FB are usually chosen so as to allow very small reconstruction error (pseudo-QMF), or even perfect reconstruction (PR). These schemes perform lossy compression, ..

The evolution of 5 GHz WLAN toward higher throughputs

A standardization effort has started within the IEEE802.11 Working Group to define the next generation of 802.11 Wireless LANs. This article illustrates how throughput achieved above the MAC layer of 5 GHz WLANs can be increased from an existing 30 Mbit/s maximum with 802.11a to rates exceeding 90 Mbit/s. After a brief review of ongoing WLAN standardization activities, the support of a higher physical layer bit rate by various standardized MAC protocols (802.11, 802.11e and HIPERLAN/2) is discussed, showing that PHY and MAC layers must be considered jointly in order to achieve a significant throughput increase. Various physical layer techniques are compared in terms of performance and complexity. Especially, simulations show that by relying on MAC layers with good efficiency like 802.11e and HIPERLAN/2, a combination of space-time block coding with a possibility of channel bundling could bring a peak throughput increase from 30 to 90 Mbit/s as well as a significant cell range increase.

Beyond WiFi 5: How to reach higher throughputs? Technological obstacles and solutions

The IEEE 802.11 High Throughput Study Group has started to define requirements for the next generation of 802.11 Wireless LANs operating in the 5 GHz band. The 802.11a standard, commercially known as WiFi 5, defines a physical layer which reaches 54 Mbit/s. However, the throughput offered to upper layers by WiFi 5 products based on the plain 802.11 MAC layer cannot exceed 30 Mbit/s for long ( 1500 bytes) packets and 10 Mbit/s for shorter (250 bytes) ones. This article investigates the technological deadlocks and solutions when trying to achieve a significant throughput increase from the current WiFi 5 limits. When increasing the PHY bit rate to hundreds of Mbit/s, the MAC overhead becomes the main limitation to a throughput increase. In this paper we compare the theoretical throughput limits of 802.11, 802.11e and the TDD/TDMA MAC of HIPERLAN/2 and conclude that current 802.11 MAC cannot be adopted as is in a future High Throughput standard, whereas TDD/TDMA and to a lesser extent 802.11e are better candidates We then present physical layer techniques which enable to reach 100 Mbit/s throughput and extended range

The Road to IMT-Advanced Communication Systems: State-of-the-Art and Innovation Areas Addressed by the WINNER+ Project

The WINNER project phases I and II contributed to the development, integration and assessment of new mobile networks techniques from 2004 to 2007. Some of these techniques are now in the 3GPP LTE and IEEE 802.16 (WiMAX) standards, while others are under consideration for LTE-Advanced and 802.16m. The WINNER+ project continues this forward-looking work for IMT-Advanced technologies and their evolutions, with a particular focus on 3GPP LTE-Advanced. This article provides an overview of the WINNER system concept and several of its key innovative components