Advanced coexistence technologies for radio optimisation in licensed and unlicensed spectrum

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Publications

Cost/revenue performance in an IMT-Advanced scenario with Spectrum Aggregation over non-contiguous frequency bands

Publication . Acevedo Flores, Jessica Elizabeth; Velez, Fernando J.; Cabral, Orlando; Robalo, Daniel Luís Silveira; Holland, Oliver; Aghvami, A. Hamid; Meucci, Filippo; Mihovska, Albena Dimitrova; Prasad, Neeli R.; Prasad, Ramjee

This paper determines the cost/revenue performance of a mobile communication system in an IMT-Advanced scenario with integrated Common Radio Resource Management (iCRRM). The iCRRM performs classic CRRM functionalities jointly with Spectrum Aggregation (SA), being able to switch users between non-contiguous frequency bands. The SA scheduling is obtained with an optimized General Multi-Band Scheduling (GMBS) algorithm with the aim of cell throughput maximization. In particular, we investigate the dependence of the throughput on the cell coverage distance for the allocation of users over the 2 and 5 GHz bands for a single operator scenario under a constant average Signal to Interference-plus-Noise Ratio (SINR), for the same type of Radio Access Technology and both frequency bands. The operator has the availability of a non-shared 2 GHz band and has access to part (or all) of a shared frequency band at 5 GHz. An almost constant gain near 30 % was obtained with the proposed optimal solution compared to a system where users are first allocated in one of the two bands and later not able to handover between the bands. It is shown that the profit in percentage terms decreases as the cell radius increases. These results allow for evaluating the impact of the revenue from the channel in the total revenue and in the profit, defined as the difference between revenues and costs, in percentage. Maximum profits of about 1270, 585 and 240 % have been obtained for prices of 0.10, 0.05 and 0.025 €/MByte, respectively, when iCRRM is employed, while profits of 990, 440, and 170 % have been reached with no iCRRM, i.e., simple CRRM. Finally, an energy efficiency strategy is proposed and analyzed, showing that there is significant transmission power saving potential through the opportunistic reallocation scheme.

2014-05Conference object

Open access

Cognitive radio for medical body area networks using ultra wideband

Publication . Chavez-Santiago, Raul; Nolan, Keith E.; Holland, Oliver; De Nardis, Luca; Ferro, João M.; Barroca, Norberto; Borges, Luís M.; Velez, Fernando J.; Goncalves, Vânia; Balasingham, Ilangko

Wearable wireless medical sensors beneficially impact the healthcare sector, and this market is experiencing rapid growth. In the United States alone, the telecommunications services market for the healthcare sector is forecast to increase from $7.5 billion in 2008 to $11.3 billion in 2013. Medical body area networks improve the mobility of patients and medical personnel during surgery, accelerate the patients’ recovery, and facilitate the remote monitoring of patients suffering from chronic diseases. Currently, MBANs are being introduced in unlicensed frequency bands, where the risk of mutual interference with other electronic devices can be high. Techniques developed during the evolution of cognitive radio can potentially alleviate these problems in medical communication environments. In addition, these techniques can help increase the efficiency of spectrum usage to accommodate the rapidly growing demand for wireless MBAN solutions and enhance coexistence with other collocated wireless systems. This article proposes a viable architecture of an MBAN with practical CR features based on ultra wideband radio technology. UWB signals offer many advantages to MBANs, and some features of this technology can be exploited for effective implementation of CR. We discuss the physical and MAC layer aspects of the proposal in addition to the implementation challenges.

2012-08Journal article

Open access

Pluralistic licensing

Publication . Holland, Oliver; De Nardis, Luca; Nolan, Keith; Medeisis, Arturas; Anker, Peter; Minervini, Leo Fulvio; Velez, Fernando; Matinmikko, Marja; Sydor, John

We introduce the concept of “pluralistic licensing”, which we describe as the award of licenses under the assumption that opportunistic secondary spectrum access will be allowed, and that interference may be caused to the primary with parameters and rules that are known to the primary at the point of obtaining the license. A key aspect of the concept is that the primary will choose from a range of offered “pluralistic licenses” each with associated fees, and each specifying alternative opportunistic access rules and associated interference characteristics. Our proposal is a novel means to take forward spectrum licensing which is fair to both primary and secondary users and takes into account the requirements of both parties. The objective is to incentivize the primary to obtain this type of license through means such as a reduced license fee, whereby the opportunistic secondary spectrum access will use “cognitive radio” mechanisms to avoid causing interference to the primary or to otherwise keep interference within known parameters. We discuss that our proposed concept can propel more robust or better design of both primary and secondary devices. For primary devices it can lead to the ability to cope with an increased degree or risk of interference among other benefits, and for secondary devices might lead to the ability to better share spectrum opportunities. Both of these aspects greatly improve spectrum usage efficiency and fairness. Our concept is also highly flexible dependent on the case-by-case deployment context, even so far as allowing solutions such as spectrum sensing and primary beacon transmissions which would otherwise not be practical or desirable, while defaulting to safe mechanisms such as a geolocation database in cases where a lower interference variance is required. Many other benefits of our concept and its extensions are discussed. We argue that “pluralistic licensing” should become the de facto form of license awarded in newly designated bands, and should also be offered to the primary as a licensing option in existing bands in cases where interference to legacy devices that might exist in the band can be avoided.

2012Conference object

Open access

Cost/revenue optimization of WiMAX networks with relay power saving modes: Measurement-Based scenario in a hilly region

Publication . Velez, Fernando J.; Oliveira, João; Robalo, Daniel; Holland, Oliver; Aghvami, Hamid

This paper investigates cell zooming and relaying in conjunction with the use of opportunistic sleep modes to save energy at times of low load in WiMAX network deployments. It performs extensive propagation measurements in a hilly area of Covilhã, Portugal, in order to present a realistic and topographically challenging scenario in which to perform dynamic optimizations. It describes these measurements and their methodology in detail. Based on this scenario, it then investigates the performance achievable by networks that are deployed in various sectorization configurations with and without relays, and matches this to varying traffic loads at different times of the day to maximise the use of sleep modes, where possible, by relays, also in consideration of coverage constraints. Results demonstrate that savings typically of 47.6% in relays' average power consumption can be achieved. These savings are shown to map to a financial saving for the operator of 10% in operation and maintenance cost combined. It is also demonstrated that such solutions have to be used cautiously in such hilly regions due to challenges in maintaining coverage.

2012-12Conference object

Open access

Opportunistic spectrum and load management for green radio networks

Publication . Holland, Oliver; Facchini, Christian; Aghvami, A. Hamid; Cabral, Orlando Manuel Brito; Velez, Fernando

Introduction Historically, the radio spectrum has been managed in a rather rigid fashion where systems have been constrained to very specific bands in order to avoid interference and maintain the spectrum's viability. This regime is extremely inefficient, because at any one time many systems are not being used thereby leaving their associated spectrum also unused. Alternative spectrum management, where systems not designated for a particular band may nevertheless use it if it is available, would greatly increase spectrumusage efficiency and capacity. Communications traffic has also historically been managed in a somewhat inefficient manner, whereby traffic load has usually only been carried on a specific band as directed by the “owner” of the user/device carrying the traffic. Improved traffic-load management techniques, where the traffic can be shared among bands and systems, would also increase efficiency or capacity. Although the end-user may sometimes have a limited choice of which band to receive traffic on (e.g. via a Wi-Fi interface using an ISM/UNII band, or via a 3G mobile communications interface using a UMTS band), centralized control of that choice, in a timely fashion, can far better manage efficiency and capacity than the end-user operating alone. Such opportunistic load and spectrum management between bands/systems is being made feasible by operators having an increasingly wide range of spectrum bands at their disposal, of very different frequencies and physical characteristics. Operators may typically operate a range of different systems on this range of spectrum bands.

2012Book part

Open access