WPR.9 - Joint RRM and Flexible use of radio spectrum

Objectives

This WP addresses the strategies to achieve an efficient management of radio resources in heterogeneous wireless networks scenarios, including cognitive radio networks. Specifically, the objectives can be summarised as:

(i) Propose, define and evaluate new Joint Radio Resource Management (JRRM) strategies for heterogeneous networks, considering the whole amount of resources in the different access technologies as a whole.

(ii) Propose, define and evaluate new Advanced Spectrum Management (ASM) mechanisms to achieve an efficient of the radio spectrum among one and different access technologies.

(iii) Introduce cognitive radio network functionalities in the JRRM and ASM mechanisms in order to provide the different systems with the ability to adapt to the different conditions.

(iv) Identify relevant scenarios and case studies where the above strategies can be applied.

Description of work

The framework for the activities in this WP assumes heterogeneous scenarios where multiple radio access technologies coexist and where flexible spectrum capabilities are enabled to achieve a more efficient use of the radio spectrum. This responds to the new trends currently followed in spectrum management and regulation pursuing on the one hand the possibility to dynamically adapt the spectrum assigned to the different technologies and cells and on the other hand to make a secondary use of the spectrum while not harmfully interfering with the primary license holders. In this framework, cognitive radio networks become a fundamental enabler of the different processes, thanks to the ability to adapt the operation of both terminals and networks to adapt to the different environmental conditions.

Based on these considerations, and the problems identified in these scenarios, the Joint Research Activities that are carried out in this WP are detailed in the following:

Task TR9.1: Joint Radio Resource Management (JRRM) strategies in heterogeneous networks.

The purpose of this task is to define and evaluate JRRM strategies aiming at an optimised usage of radio resource and maximized system capacity in a scenario with multiple radio networks and with the necessary support of reconfigurable/multimode terminals. Particular focus will be given to the integration of Hierarchical Wireless Hybrid Networks, which represent the merging of wireless sensor networks and other wireless technologies, like e.g., cellular systems (e.g., UMTS) and broadband wireless systems (e.g., WLANs and WiMAX). Here the impact of RRM techniques jointly performed over the different wireless systems involved is to be analysed.

Main players: IST-TUL, CNIT.

TR9.2: Spectrum allocation for OFDMA networks.

The objectives to be fulfilled in the framework of this activity are to study and define algorithms for allocating power and subcarriers for OFDMA systems in single- and multi-cellular scenarios. This also includes the assignment of carriers to the different cells above the scheduling level that decides the assignment of carriers to users. The analysis will aim at finding efficient solutions with a low-complexity implementation. Under the hypothesis of a distributed system where no coordinated information is exchanged between cells, the group aims to implement a network with (quasi) full reuse of the available spectral resources.

Main Players: CNIT, UPC, PUT.

TR9.3: Game Theory for optimisation of RRM, distributed algorithms for CR.

A game theoretical framework is in fact perfectly adapted to the cognitive radio concept, where the intelligence and decision making is distributed, i.e. split between the network and the user equipment and thus scalable. The objective of this work is to define innovative schemes using distributed cognitive mechanisms in a wireless multiuser system. Basically, the purpose of the work is to understand the problem of cognitive radio in a deregulated context, to model problems to be solved using game theory approach using various equilibrium concepts (Nash, Wardrop, Stackelberg, etc.) and to propose simple strategies and algorithms to solve the game (e.g., introduce also pricing to find efficient operating point). The proposed strategies will be validated by analytical or simulation approach. Comparison with ``traditional'' resource allocation should be done too.

Main Players: PUT, CNRS.

TR9.4: Measurements to detect spectrum availability.

The basic principle of spectrum sharing techniques relies in allowing certain unlicensed users to access some licensed radiofrequency bands when they are not being used by any licensed user. Hence, unlicensed opportunistic access to spectrum is allowed provided that no harmful interference is caused to legitimate users. This will result in increased spectrum usage efficiency. Under this framework, the purpose of this activity is to make a measurement campaign in order to have a clear picture of how different frequency bands are being utilised in specific environments. This will allow studying and analysing the availability of temporarily unoccupied spectral resources in terms of frequency, time, and space, and to identify the most suitable and interesting bands for the deployment of future Cognitive Radio Networks or Dynamic Spectrum Access Networks. This activity will also explore the possibility to use the obtained measurements in the development of the standard recognition sensor.

Main Players: UPC, CNRS.

TR9.5: Cognitive Radio Network based on Sensorial radio bubble.

The Sensorial Radio Bubble (SRB) gives to Cognitive Radio communication systems the ability to explore the radio environment in order to provide knowledge of the spatial and spectrum environment, and some context awareness. Such a Cognitive Radio system knows all about the signals coming inside and going outside its bubble, as well as the state of many parameters inside the bubble (positioning, other terminals, overall load for every standard in the bubble, etc.). This permits the terminal to securely transmit its communications with a guaranteed QoS, taking into account the state of all these parameters. That is why it can be also spoken about the “security bubble”. Two analogies, with traffic code and human physiological bubble, can be studied to simply explain the concept. One of the contributions of the SRB is to manage spectrum resources with more efficiency. This bubble relies on a plurality of sensors based on signal processing techniques. Then, in this activity, it is proposed to build Cognitive Radio networks based on SRB concept.

Main players: CNRS, UPC, CNIT