Spectrum pooling: an innovative strategy for the enhancement of spectrum efficiency
TL;DR: The technical challenges that have to be met when implementing the interesting new technology of spectrum pooling are described, which represents the coexistence of two mobile radio systems within the same frequency range.
Abstract: This article describes the technical challenges that have to be met when implementing the interesting new technology of spectrum pooling. This notion represents the coexistence of two mobile radio systems within the same frequency range. It enables the secondary utilization of already licensed frequency bands as aimed at by several regulatory authorities worldwide. The goal of spectrum pooling is to enhance spectral efficiency by overlaying a new mobile radio system on an existing one without requiring any changes to the actual licensed system. Several demanding tasks originate from this idea. Some of them have been solved in recent research projects. Others are subject to ongoing investigations. Here, the state of the art in spectrum pooling is presented.
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TL;DR: The novel functionalities and current research challenges of the xG networks are explained in detail, and a brief overview of the cognitive radio technology is provided and the xg network architecture is introduced.
6,608 citations
Cites background from "Spectrum pooling: an innovative str..."
...Hence, xG networks can be deployed to exploit these spectrum holes through cognitive communication techniques....
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TL;DR: An overview of challenges and recent developments in both technological and regulatory aspects of opportunistic spectrum access (OSA) is presented, and the three basic components of OSA are discussed.
Abstract: Compounding the confusion is the use of the broad term cognitive radio as a synonym for dynamic spectrum access. As an initial attempt at unifying the terminology, the taxonomy of dynamic spectrum access is provided. In this article, an overview of challenges and recent developments in both technological and regulatory aspects of opportunistic spectrum access (OSA). The three basic components of OSA are discussed. Spectrum opportunity identification is crucial to OSA in order to achieve nonintrusive communication. The basic functions of the opportunity identification module are identified
2,819 citations
Cites background from "Spectrum pooling: an innovative str..."
...Since secondary users may need to transmit over noncontiguous frequency bands, OFDM is an attractive candidate for modulation in OSA networks [ 29 ]‐[31]....
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TL;DR: It is shown that filter bank multicarrier (FBMC) could be a more effective solution to the shortcomings of orthogonal frequency division multiplexing in certain applications and in other applications.
Abstract: As of today, orthogonal frequency division multiplexing (OFDM) has been the dominant technology for broadband multicarrier communications. However, in certain applications such as cognitive radios and uplink of multiuser multicarrier systems, where a subset of subcarriers is allocated to each user, OFDM may be an undesirable solution. In this article, we address the shortcomings of OFDM in these and other applications and show that filter bank multicarrier (FBMC) could be a more effective solution. Although FBMC methods have been studied by a number of researchers, and some even before the invention of OFDM, only recently has FBMC been seriously considered by a few standard committees.
1,304 citations
TL;DR: This paper provides a systematic overview on CR networking and communications by looking at the key functions of the physical, medium access control (MAC), and network layers involved in a CR design and how these layers are crossly related.
Abstract: Cognitive radio (CR) is the enabling technology for supporting dynamic spectrum access: the policy that addresses the spectrum scarcity problem that is encountered in many countries. Thus, CR is widely regarded as one of the most promising technologies for future wireless communications. To make radios and wireless networks truly cognitive, however, is by no means a simple task, and it requires collaborative effort from various research communities, including communications theory, networking engineering, signal processing, game theory, software-hardware joint design, and reconfigurable antenna and radio-frequency design. In this paper, we provide a systematic overview on CR networking and communications by looking at the key functions of the physical (PHY), medium access control (MAC), and network layers involved in a CR design and how these layers are crossly related. In particular, for the PHY layer, we will address signal processing techniques for spectrum sensing, cooperative spectrum sensing, and transceiver design for cognitive spectrum access. For the MAC layer, we review sensing scheduling schemes, sensing-access tradeoff design, spectrum-aware access MAC, and CR MAC protocols. In the network layer, cognitive radio network (CRN) tomography, spectrum-aware routing, and quality-of-service (QoS) control will be addressed. Emerging CRNs that are actively developed by various standardization committees and spectrum-sharing economics will also be reviewed. Finally, we point out several open questions and challenges that are related to the CRN design.
980 citations
Cites background from "Spectrum pooling: an innovative str..."
...been discussed in [59], where several potential problems for realizing the pooling scheme have been identified, among which,...
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17 May 2004
TL;DR: A quantitative comparison of both approaches to spectrum pooling aims at enabling public access to these spectral ranges without sacrificing the transmission quality of the actual license owners, and it is obvious that both approaches sacrifice bandwidth of the rental system.
Abstract: The public mobile radio spectrum has become a scarce resource while wide spectral ranges are only rarely used. Here, the new strategy called spectrum pooling is considered. It aims at enabling public access to these spectral ranges without sacrificing the transmission quality of the actual license owners. Unfortunately, using OFDM modulation in a spectrum pooling system has some drawbacks. There is an interaction between the licensed system and the OFDM based rental system due to the non-orthogonality of their respective transmit signals. This interaction is described mathematically, providing a quantitative evaluation of the mutual interference that leads to an SNR loss in both systems. However, this interference can be mitigated by windowing the OFDM signal in the time domain or by the adaptive deactivation of adjacent subcarriers providing flexible guard bands between licensed and rental system. It is obvious that both approaches sacrifice bandwidth of the rental system. A quantitative comparison of both approaches is given as a tradeoff between interference reduction and throughput in the rental system.
642 citations
Cites background from "Spectrum pooling: an innovative str..."
...A detailed description of this approach is given in [5]....
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...It is assumed that the LS subbands are co-located with single subcarriers or sets of subcarriers [5]....
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References
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15 Nov 1999
TL;DR: This paper characterizes the potential contributions of cognitive radio to spectrum pooling and outlines an initial framework for formal radio-etiquette protocols.
Abstract: Wireless multimedia applications require significant bandwidth, some of which will be provided by third-generation (3G) services. Even with substantial investment in 3G infrastructure, the radio spectrum allocated to 3G will be limited. Cognitive radio offers a mechanism for the flexible pooling of radio spectrum using a new class of protocols called formal radio etiquettes. This approach could expand the bandwidth available for conventional uses (e.g. police, fire and rescue) and extend the spatial coverage of 3G in a novel way. Cognitive radio is a particular extension of software radio that employs model-based reasoning about users, multimedia content, and communications context. This paper characterizes the potential contributions of cognitive radio to spectrum pooling and outlines an initial framework for formal radio-etiquette protocols.
1,331 citations
16 Jan 2004
366 citations
07 Aug 2002
TL;DR: The spectrum utilization, blocking probability and forced termination probability for these two different channel access schemes are compared.
Abstract: Spectrum for mobile networks is becoming scarce and on the other hand plenty of sporadically used frequencies exist. The spectrum utilization of such spectra is very low, which is a reason to think about a way to make them available for commercial purpose without a drawback for the license owners. We recommend a strategy called spectrum pooling which is based on this idea. The notion spectrum pool was first mentioned by Mitola III (see Proc. IEEE International Workshop on Mobile Multimedia Communications, p.3-10, 1999). In a spectrum pooling system the license owner of the spectrum allows priorly specified candidate renters to use his spectrum until he needs his spectrum himself. The renters of the spectrum may be treated in two different ways. One way is that communication processes of spectrum renters can persist as long as there are channels for the processes of the license owners. The other way is that the owner has no knowledge whether the channels are occupied by renters or not and treat the channels used by renters like free channels. In both cases the renters have to measure the interference level in the channel after dedicated time intervals and have to leave the channel within the time interval T/sub p/ as soon as the interference exceeds a prior specified threshold. We compare the spectrum utilization, blocking probability and forced termination probability for these two different channel access schemes.
98 citations
01 Jan 2003
TL;DR: In this paper, the authors proposed a spectrum pooling scheme to enable public access to these new spectral ranges without sacrificing the transmission quality of the actual license owners, which is a new strategy called Spectrum Pooling.
Abstract: Public mobile radio spectrum is a scarce resource while wide spectral ranges are only rarely used. Here, we consider a new strategy called Spectrum Pooling enabling public access to these new spectral ranges without sacrificing the transmission quality of the actual license owners. By temporarily leasing their spectrum during idle periods the license own- ers could tap new sources of revenue. We favor a modified wireless LAN as rental system. Especially OFDM based WLANs like IEEE802.11a and HIPERLAN/2 are suitable for an overlay system like spectrum pooling as they allow a very flexible frequency management on a carrier-by-carrier basis. The modifications of these standards comprise many areas of the physical and MAC layer. Idle frequency subbands can be detected by spec- tral power measurements conducted in each single participating mobile ter- minal. Hence, the volume of measurement data can become very high. Sig- naling this overhead in ordinary data frames would leave only few resources left for useful data and would be very error-prone. In this paper, we show that the signaling of spectral resources can be performed in the physical layer that has been harmonized for both considered standards. The basic idea is the superposition of emitted radio power for the signaling instead of creating new higher layer frames for the measured data. Furthermore, a robust method to broadcast information on spectral resources back to the mobile terminals is presented.
97 citations
TL;DR: The author presents the case for a better to approach to spectrum use involving a pragmatic and searching fashion rather than with an ideological mind set that equates the free market with one and only one particular allocation technique.
Abstract: The author presents the case for a better to approach to spectrum use involving a pragmatic and searching fashion rather than with an ideological mind set that equates the free market with one and only one particular allocation technique Spectrum auctions are considered as an application for present times The author goes on to look at the future
94 citations