https://www.cs.montana.edu/courses/csci566/Ref/CR-Survey.pdf

NeXt generation/dynamic spectrum access/cognitive radio wireless networks: a survey

Cognitive radio allows for usage of licensed frequency bands by unlicensed users. However, these unlicensed (cognitive) users need to monitor the spectrum continuously to avoid possible interference with the licensed (primary) users. Apart from this, cognitive radio is expected to learn from its surroundings and perform functions that best serve its users. Such an adaptive technology naturally presents unique signal-processing challenges. In this paper, we describe the fundamental signal-processing aspects involved in developing a fully functional cognitive radio network, including spectrum sensing and spectrum sculpting.

Signal Processing in Cognitive Radio

We consider the problem of opportunistic dynamic spectrum access (DSA) in an ad hoc network in which unlicensed secondary users communicate through channels not used by the primary users. Decentralized cognitive medium access control protocols are presented that allow secondary users to recognize spectrum opportunity and transmit based on a partial observation of the instantaneous spectrum availability. Under a framework of partially observable Markov decision process (POMDP), we derive optimal and suboptimal decentralized strategies for the secondary users to decide which channel(s) to sense and access for the maximization of the overall network throughput

/pdf/decentralized-cognitive-mac-for-dynamic-spectrum-access-yp9ig9ivjo.pdf

Decentralized cognitive mac for dynamic spectrum access

The radio research community has aggressively embraced cognitive radio for dynamic radio spectrum management to enhance spectrum usage, e.g., in ISM bands and as secondary users in unused TV bands, but the needs of the mobile wireless user have not been addressed as thoroughly on the question of high quality of information (QoI) as a function of place, time, and social setting (e.g. commuting, shopping, or in need of medical assistance). This paper considers the evolution of cognitive radio architecture (CRA) in the context of motivating use cases such as public safety and sentient spaces to characterize CRA with an interdisciplinary perspective where machine perception in visual, acoustic, speech, and natural language text domains provide cues to the automatic detection of stereotypical situations, enabling radio nodes to select from among radio bands and modes more intelligently and enabling cognitive wireless networks to deliver higher QoI within social and technical constraints, made more cost effective via embedded and distributed computational intelligence.

Cognitive Radio Architecture Evolution

Methods and system are provided for managing and monitoring allocation of RF spectrum resources based on time, space and frequency. A network may be enabled to allocate excess spectrum resources for use by other network providers on a real-time basis. Allocated resources may be transferred from one provider with excess resources to another in need of additional resources based on contractual terms or on a real-time purchase negotiations and settlements. A network may be enabled to monitor the use of allocated resources on real-time basis and off-load or allow additional users depending on the spectrum resources availability. Public safety networks may be enabled to make spectrum resources available to general public by allocating spectrum resources and monitoring the use of those resources. During an emergency, when traffic increases on a public safety network, the public safety networks may off-load bandwidth traffic to make available necessary resources for public safety users.

Methods and systems for dynamic spectrum arbitrage

Future wireless systems are expected to be characterized by increasing convergence between networks and further development of reconfigurable radio systems. In parallel with this, demand for radio spectrum from these systems will increase, as users take advantage of high quality multimedia services. This article aims to investigate and review the possibilities for the dynamic allocation of spectrum to different radio networks operating in a composite reconfigurable wireless system. The article first looks into the current interest of regulators in this area, before describing some possible schemes to implement dynamic spectrum allocation and showing some example performance results. Following this, the technical requirements that a DSA system would have, in terms of reconfigurable system implementation, are discussed.

Dynamic spectrum allocation in composite reconfigurable wireless networks

A cellular communication system comprises a set of base stations (201,203) which transmit downlink resource exchange discovery messages to remote terminals in resource allocations of a Media Access Control, MAC, frame structure. The discovery messages may indicate that a base station has resource available for reallocation to another base station or that a base station is seeking resource to be allocated from another base station. A remote terminal (205) comprises a receiver (401, 403) which receives a first message of the downlink resource exchange discovery messages from at least a first base station (201). A discovery message transmit processor (407) generates a second message, which is an uplink resource exchange message comprising resource exchange data determined from the first message, and transmits this to a second base station (203). The second base station (203) then initiates a temporary air interface resource reallocation with the first base station in response to receiving the second message.

Resource exchange discovery in a cellular communication system

The E2R II Flexible Spectrum Management (FSM) Framework and Cognitive Pilot Channel (CPC) Concept – Technical and Business Analysis and Recommendations (E2R II White Paper)

The innovative communications services and applications imposed by ever increasing customer demands render necessary the development of efficient radio resource exploitation mechanisms and intelligent network planning methods. The whole process of planning and managing a reconfigurable network must be reconsidered, in order to live up to the expectations created by the migration towards a new era of communications. This White Paper deals with such issues, emphasizing the role of new engineering technologies in reconfigurable networks. For this purpose, it presents the respective Radio Resource Management, i.e. Spectrum Management and Joint Radio Resource Management, and Network Planning technical approaches, aiming at their application in next generation wireless access infrastructures.

Cognitive Radio, Spectrum and Radio Resource Management

An apparatus for resource sharing between a plurality of communication networks (103, 107, 111) each having a nominal resource allocation of a shared air interface resource and a resource exchange allowance is provided. The apparatus (201) comprises a sharing instigation processor (205) which initiates a temporary resource allocation of a first air interface resource from a nominal resource allocation of a first network (103). A network interface (201) receives offer messages from a plurality of networks (107, 111). Each offer message comprises a resource exchange offer value for at least part of the first air interface resource. A selection processor (207) selects a second network (107) for example by selecting the highest offer value for a given resource. An allocation message generator (211) transmits a resource allocation message to the second network (107) indicating a temporary allocation of at least part of the first air interface resource. The resource exchange allowance of the second network (107) is then reduced by a value corresponding to the resource exchange offer value from the second network (107).

David Grandblaise

Papers

Dynamic spectrum allocation in composite reconfigurable wireless networks

Resource exchange discovery in a cellular communication system

The E2R II Flexible Spectrum Management (FSM) Framework and Cognitive Pilot Channel (CPC) Concept – Technical and Business Analysis and Recommendations (E2R II White Paper)

Cognitive Radio, Spectrum and Radio Resource Management

Apparatus and method for resource sharing between a plurality of communication networks