Spectrum Management

An Information Divide Needs to be Avoided While Digital is Accessible to all Citizens
“Access to information is a basic right of all citizens of the world. At a time when we are working hard to
make sure there is no digital divide, digital access should not create an information divide by presenting
barriers to the access to information”.

This paper seeks to assess radio-spectrum refarming in selected African countries. It provides an overview of the debate around spectrum refarming and it presents case studies that offer insights into the African context. This discussion identifies regulatory constrains hindering an optimal usage of premium frequencies and provides policy and regulatory recommendations on how to facilitate spectrum refarming.
Findings show that the analysed African regulatory environments have implemented a technology-neutral licensing regime to enhance competition. Although this regulatory intervention opened up the market by enhancing market opportunities and granting additional licenses, some of the new licensees cannot begin operations because of an artificially created scarcity of spectrum. Further, new licensing frameworks have created a competitive advantage for those operators already holding premium frequencies, as they can refarm assigned spectrum bands positioning themselves as both voice and data service providers.
In addition, due to regulatory delays in liberalising and refarming frequencies suitable for wireless broadband roll-out such as 2.6GHz and 3.5GHz, incumbent operators are merging with smaller telcos, in order to access additional spectrum for the provision of wireless broadband services. This is leading to a spectrum hoarding.

The need for Digital Transmission has been on the increase over the years. Spectrums are basically a range of electromagnetic waves for digital transmission. Digital Transmission has poised great economic benefits to Networks Transmission Industries. However, with the wide spread demand for networks transmission, appropriate supervision of utilization and management is adequately required. A key component of the study is based on the input from the operational regions, industry stakeholders and Government Commissions. The study observed that, digital transmission has helped in managing the rate at which available spectrums are been utilized. Indeed, it takes 8MHz (Eight Mega Hertz) of Spectrum to carry a single Analogue Transmission, but with, Digital Transmission, it take the same 8MHz (Eight Mega Hertz) of Spectrum to carry as much as 20 (twenty) Digital Transmissions. This research work focused on providing solution to the need for a proper Analysis of Digital Spectrum Utilization. The concept of a Fuzzy Set, and a robust analytic tool (MATLAB) was used as the analytic system model for a more scientific and feasible solution to sensitivity analysis and spectrum utilization. The system was developed and evaluated using a scientific field data obtained from Nigerian Television Authority (NTA) Jos, for analysis purpose. Results obtained from the analysis shows that the use of Spectrum for Digital Transmission in Nigeria (Jos) has periodically increased, however not up to 50% (fifty per cent) were in use as at the end of December 2016. Recent concerns for conversion of Analogue Transmission to Digital are expected to bring about significant increase to Spectrum Utilization in Nigeria.

An unprecedented transformation in the design, deployment, and application of short-range wireless devices and services is in progress today. This trend is in line with the imminent transition from third- to fourth-generation radio systems, where heterogeneous environments are expected to prevail eventually. A key driver in this transition is the steep growth in both demand and deployment of WLANs/WPANs based on the wireless standards within the IEEE 802 suite. Today, these short-range devices and networks operate mainly standalone in indoor home and office environments or large enclosed public areas, while their integration into the wireless wide-area infrastructure is still nearly nonexistent and far from trivial. This status quo in the short-range wireless application space is about to be disrupted by novel devices and systems based on the emerging UWB radio technology with the potential to provide solutions for many of today's problems in the areas of spectrum management and radio system engineering. The approach employed by UWB radio devices is based on sharing already occupied spectrum resources by means of the overlay principle, rather than looking for still available but possibly unsuitable new bands. This novel radio technology has received legal adoption by the regulatory authorities in the United States, and efforts to achieve this status in Europe and Asia are underway. This article discusses both the application potential and technical challenges presented by UWB radio as an unconventional but promising new wireless technology.

Cognitive radio is one of the technologies promoting flexible and efficient use of radio frequency spectrum, thus solving spectrum scarcity problem. Frequency assignment is an integral part of the cognitive radio spectrum management and a critical point of success or failure of the cognitive radio concept. In this paper, cognitive radio frequency assignment with a novel interference weighting and categorization is proposed, as an extension of the solution to the graph coloring problem. In our approach, the edge weights quantifying the interference potential are appended to the conflict graph, co-and adjacent channel interference are treated, and dynamically changing local lists of blocked frequencies are included. We propose the improved cognitive radio saturation metric for the dynamic vertex ordering and to introduce interference categorization which will reduce the communication overhead. Using the proposed model, resource manager can quantify individual interference components, as well as aggregate interference from multiple users, resulting in more knowledgeable frequency decisions. Generalization of the proposed model is suggested. The suggested generalization consists of the selection of the central frequency and optimal bandwidth to be used, according to the user requirements. We have developed interference-sensitive algorithms for minimizing the interference and maximizing the throughput, both in centralized and distributed implementation. The results show significant reduction of the interference, improved spectrum efficiency, and increase in network throughput, comparing to the benchmark algorithms.

Wireless Technologies are being used extensively for telecommunication services, thus increasing the demand for frequency spectrum. Regulators are pushed to allocate spectrum efficiently resulting in increased possibility of interference. Interference management becomes a challenge if the same spectrum is allocated to different network operators in neighboring geographic areas. Operators generally use coordinated frequency/PN Offset planning to mitigate such interference. The problem becomes complicated if the adjacent geographic areas fall in different countries. ITU and Regional Regulatory bodies provide guidelines for coordinated spectrum allocations across international borders; however, some scenarios are not addressed. One such problem is faced by an EGSM operator in Pakistan which is facing severe interference from CDMA operators in India. Coordinated frequency/PN Offset planning is not possible in this cross-technology interference scenario. Furthermore, the effect of this interference is only observed on the EGSM side, while CDMA is not impacted. This paper describes the unique interference problem of the EGSM operator in Pakistan and describes a process adopted for analysis and mitigation of this interference.

The WiMAX (IEEE 802.16) technology offers a mechanism to create a multi-hop mesh network and provides a low cost alternative to the cabled access networks. This paper proposes a fuzzy rule based channel allocation technique for efficient spectrum management in multi-channel IEEE 802.16 network (WiMAX). The Subscriber Stations are categorized on the basis of their average traffic pattern. The frequency use by the network is optimized through re-allocation of sub-carrier frequency without degrading the QoS. Simulation using Matlab have been used to demonstrate the effectiveness of the proposed method in terms of Channel Utilization Ratio and Channel Acquisition Delay.

A worldwide survey of regulations and standards in 235 countries reveals different approaches associated with RADHAZ and spurious emissions. These are primarily divided into regions regulated or influenced by Europe or by North America, each applying different limits to cellular base stations, utility power lines and spurious emissions. Generally, the American and Japanese permitted exposures are more lenient, whereas the European are stricter. Several interesting examples are discussed.

This Spectrum occupancy measurement in many countries shows sporadic and poorly utilized licensed radio spectrum due to the outdated exclusive spectrum access policy. Dynamic Spectrum Access (DSA) technique allows cognitive (unlicensed) user (CU) to opportunistically transmit in a primary (licensed) user (PU) frequency band for a given time if it does not detect any ongoing operations. In this work, DSA is realized using cognitive radio (CR) technology due to its features of able to sense, learn, adapt and react according to the environment. The proposed design of the DSA based CR system consists of four main functional blocks: spectrum sensing, spectrum management, spectrum decision and data transmission. The implementation is done using GNU Radio and Universal Software Radio Peripheral (USRP) Software Defined Radio (SDR) platform. The result shows a significant improvement in term of Packet Reception Rate (PRR) in DSA based CR systems compared to the system without DSA capability.

Recently, the Dynamic Spectrum Access (DSA) techniques are proposed to solve the problem of spectrum scarcity and help to use the limited spectrum resource as effectively as possible. The current ongoing spectrum reform opens up the possibilities to exploit the DSA techniques. This paper aims to provide a critical review on the various ongoing efforts towards the use of DSA concept for the frequency management of future wireless communications systems, especially from the Cognitive Radio (CR) perspective. The CR aims for an efficient and dynamic access to the spectrum, and provides a new method of spectrum management. This paper also highlights the various challenges associated with CR in order to realize the concept of DSA.