On-line spectrum auctions in TV white spaces for supporting mobile services—A practical manual

This paper considers an approach for dynamic short-term spectrum leasing in TV white spaces (TVWS) using an on-line auction. The secondary spectrum market discussed here is organized by a central entity called the spectrum broker. The auctioned spectrum appears in blocks of available DVB-T channels with some transmit power constraints set-up to protect the primary users (DVB-T receivers). The bidders are institutional spectrum operators (telecommunication companies or service providers), operating in a given area. These players are characterized by heterogeneous demands concerning the spectrum bandwidth, the operation period with temporarily-exclusive rights for using the spectrum and the transmit power needed for successful transmission. Thus, the auctioned objects are non-identical and present different value for different players. Two auction models are proposed. The first one is the simultaneous auction in time domain and combinatorial in frequency and power dimension. The second proposed auction is fully combinatorial. Simulations results are also provided showing effectiveness of the analyzed auctions (high spectrum utilization ratio) and relation between the players’ satisfaction, their spectrum valuation and varying competition. Finally the guidelines concerning the spectrum auctions in TVWS for the policy makers are proposed.     

Transmitters and receivers' investment to avoid interference: Is there an optimal regime?

The management of interference has been, and still is, the main concern in spectrum policy. Historically, interference has been dealt with by heavy regulation under an administrative control regime. Over the last decades, a new approach has been put forward based on users' property rights, better able to cope with a rapidly changing technological environment. The issue of dealing with interference across bands, however, remains crucial: What obligations should be put on users so as to keep interference at a socially acceptable level? Also, given that some unwanted emissions are bound to occur, how can private parties be provided with the right incentives to invest in high-quality reception technology? This paper assesses how well different regulatory regimes can lead to efficient outcomes. It develops an economic model of spectrum interference and identifies the efficient solution. A regime where spectrum users have the power to enjoin intruding emissions beyond a predefined level (property rights protection) is compared with a regime where users are forced to bear with intruding emissions, but are entitled to economic compensation for the harm suffered (liability rules protection). The analysis suggests that different regimes may perform differently under different circumstances depending on the cause of interference and, critically, on whether the services are organised as an open- or a close-architecture system. This suggests that regulators should pay more attention to the specific features of the different bands, and that the appropriate spectrum management regime should be designed to recognise these differences.     

Mechanisms to incentivise shared-use of spectrum

A key concern with the Licensed-shared access (LSA) approach currently being developed by European regulators is that leaving incumbents and secondary users to agree to bilateral arrangements may be insufficient to incentivise an optimal level of sharing.We propose an efficient auction mechanism to incentivise incumbent users to offer shared access to the spectrum they use. The mechanism consists of two stages. In the first stage, LSA licences are auctioned. In the second stage, the incumbent is provided with a choice of either granting access under an LSA agreement to the winner of the auction or not. If the incumbent accepts, its existing licence fee is reduced, whereas, if it rejects, its existing licence fee is increased. The change in the licence fee is such that a rational incumbent always opts to share when it is efficient to do so, i.e. when the cost of sharing is below the value to the secondary user.We also explore how this simple mechanism can be extended to situations in which there is more than one incumbent in a band. Our proposed approach involves package (combinatorial) bidding and linear reference prices.     

Setting licence fees for renewing telecommunication spectrum based on an auction

This paper presents a methodology for setting fees for the renewal or extension of spectrum licences, by using the outcome of an auction for comparable licences but with a different licence period. The methodology is a combination of market and cash flow valuation and consists of two main steps. First, prices for spectrum corresponding to that of the licences to be extended are derived from the auction outcome. Second, the relative value addition of the extension period for the new licensee, compared to the value of the licences auctioned, is derived by using a model for the development of EBITDA for an operator over time. A combination of these two is used to calculate fees that match the opportunity costs of extension. Thus, optimum alignment is achieved with the policy objective of using licence fees only to promote efficient use of spectrum, while avoiding state aid at the same time.     

Spectrum sharing in the gray space

There has been considerable effort to let more wireless devices operate in white space spectrum, that is within frequency bands and geographic areas where no wireless devices are active. Making white space available is certainly useful, but there are other sharing opportunities as well, some of which have been obscured by dangerous misconceptions about the concept of unused spectrum. This paper discusses allowing more devices to operate safely in gray space spectrum, that is spectrum that is actively being used in that transmissions are underway—something many economic models assume is impossible. The paper focuses on primary–secondary sharing, so devices gaining access to spectrum operate on a secondary basis in a way that never causes harmful interference to primary systems. Examples of primary–secondary gray space sharing mechanisms are described in which devices are allowed to share spectrum with broadcasting, radar, and cellular systems. Quantitative analysis shows that it is technically possible to support significant communications among secondary devices in spectrum that is already heavily used by cellular or radar. However, gray space sharing generally causes primary and secondary systems to be more technically interdependent than white space sharing, so different policy and governance structures are needed. Secondary market rules can support gray space sharing in cases where there is a single primary spectrum user, such as a cellular carrier. In cases where technology is static, the regulator may be able to control access for secondary devices. However, in cases with multiple primary users and multiple secondary users of spectrum, as might be seen in bands with radar for example, a new kind of governance body will be needed to facilitate spectrum sharing.     

Alternative radio licensing arrangements: A case study of the multipoint distribution service

Currently, the FCC assigns radio licences after making a determination of the public interest. Conflicting licence applications are resolved through comparative hearings. This mechanism is cumbersome and unreliable. This article analyses three alternatives: Increasing the available spectrum; an auction; or, lottery of radio licences. The analysis deals specifically with the Multipoint Distribution Service (MDS). The analysis suggests that increasing the spectrum allocation will create more assignments than will be demanded by MDS. Rough calculations suggest that auctions offer a more efficient selection mechanism. Lotteries with resale of the license are better than hearings, but not as good as auctions.     

卫星通信中交叉极化干扰现象与处理方法

交叉极化干扰在卫星通信中不可避免,只能尽量减小。通过分析卫星通信中交叉极化干扰产生的原因以及干扰发生时信号的频谱特征,指出了交叉极化干扰可能影响到的三类用户:网内主极化用户本身、相邻频段网内其他用户和另外一个交叉极化转发器同频段的用户。最后给出了尽量减少交叉极化干扰的处理方法。     

Beachfront commons

Technology competition between wireless communication technologies can lead to new, more or less disruptive services. A potentially disruptive technology would be to have unlicensed transmission in the lower UHF bands at power levels up to, e.g. 2 W EIRP. This would give citizens a share of the best spectrum for free use. Tools against congestion could be based on mandatory stochastic channel back-off or, if multiple users are present, on adaptive power and bandwidth control. Compared to the FCC TV white space regulation, no back link would be needed as the spectrum would be used exclusively by wireless devices. In an environment of shrinking interest in terrestrial TV broadcasting, such a regulation is expected to create a new market for high-range consumer devices, competing with licensed communication, while also being suitable for offloading traffic from licensed operations. Furthermore, the approach will allow for efficient digitization of equipment for Programme Making and Special Events (PMSE), but could also be made compatible with novel disaster relief services. To enable accurate interference prediction, it is proposed that, instead of only providing transmitter regulation, receivers should also be regulated, such as be required to adhere to a certain minimum selectivity. The proposal should be taken up in the WRC process.     

IS THE GENERAL PUBLIC LICENCE A RATIONAL CHOICE?*

Open source projects are networks of developers, distributors and end‐users of non‐proprietary created knowledge goods. It has been argued that this form of organization has some advantages over the firm or market coordination. I show that for sufficiently convex and modular projects, proprietary licences are not able to sustain sequential knowledge production which, however, can be carried out if the project is run on the open source basis.     

DOES COPYRIGHT ENFORCEMENT ENCOURAGE PIRACY?*

When copyright enforcement is targeted at high‐value buyers such as corporate and government users, the copyright holder charges super‐monopoly prices, thereby encouraging low‐value buyers to switch to inferior pirated copies. We show that enlarging the copyright holder's captive market through more extensive copyright enforcement reduces prices toward the monopoly level, increases sales of legitimate copies and can increase consumer surplus. Therefore, in contrast with the case of more intensive copyright enforcement, more extensive copyright enforcement over some range can increase the incentive to generate intellectual property while also reducing the loss to consumers from monopoly power.     

Telecommunications reform in Botswana: a policy model for African states

Since the mid-1990s, Botswana has pursued a policy of telecommunications liberalisation. This article, based on fieldwork conducted in Botswana in the summer of 2000, analyzes several notable aspects of the process of reform and denotes those worthy of emulation by other African states. The participation and protection of domestic telecommunication users, transparency in decision-making, the creation of an independent regulatory agency, and the introduction of competition in the form of private cellular service providers are among those policy features that are recommended for replication. Various facets of the tendering process and subsequent licences granted to the mobile operators as well as recent legislation are also examined and commended.     

Dynamic usage of narrowband spectrum

We examine the potential for expansion of the white space spectrum sharing model in the 400 MHz band. As opposed to UHF broadcast spectrum, which contains unassigned or idle segments known as white spaces, the 400 MHz band is characterised by intensive licence usage. However, productive spectrum usage does not guarantee allocative efficiency, which would require knowledge of the highest value service for each licence. 400 MHz frequencies are not priced on opportunity cost. It is therefore difficult to ascertain the economically efficient mix of services to deploy in the 400 MHz band. Drawing parallels with the high-economic value revealed and generated through the operations of unlicensed white space devices in UHF broadcast spectrum, we identify untapped 400 MHz spectrum capacity, which we refer to as narrowband spaces. Encouraging dynamic spectrum usage of narrowband spaces could, similarly to TV white space usage help realise the efficient allocation of the 400 MHz band. However, the narrowband nature of the 400 MHz licences and high licensing turnover imply a significantly different concept of dynamic spectrum access than that considered for TV Bands. The paper discusses regulatory implications and the type of services suited to exploit narrowband spaces.     

Economic viability of private commons: Framework and guidelines for profitability

Ongoing regulatory reforms have led to several novel spectrum sharing models under the general umbrella of dynamic spectrum sharing. The private commons model introduced by FCC in 2004 allows spectrum licensees to provide secondary access to spectrum on an opportunistic basis while retaining ownership. Since wireless communication systems are typically overprovisioned in order to deliver service-level guarantees to (primary) users under short-term load variations, this model bears significant potential by facilitating utilization of temporal and spatial surplus of capacity through serving secondary users at possibly different service levels. A potential barrier to adoption of the private commons model is the uncertainty about secondary price–demand relationship which is difficult to predict in an emerging market: A selected price for secondary access may be profitable for some values of secondary demand but not for others, leading to a profound uncertainty about ultimate benefit of spectrum sharing. This paper aims to eliminate such an uncertainty by devising concrete guidelines and methods for profitability. The paper establishes that the price of secondary spectrum access can be chosen to guarantee profitability for any value of secondary demand: It is shown that for both the coordinated and uncoordinated commons regimes a profitable price should exceed a threshold value, which can be calculated. Hence profitability of private commons is insensitive to the demand function. This observation has two complementary interpretations: From a business perspective it provides a constructive approach to profitability; and from a regulatory perspective it provides reassurance that private commons is a healthy model. The paper also leverages the insensitivity property and outlines a technique to further enhance revenue via iterative spectrum offerings.     

Financial and operational decisions in the electricity sector: Contract portfolio optimization with the conditional value-at-risk criterion

The restructuring of electricity markets around the world have caused increased volatility and uncertainty of the price power. As a result, providers of power now face increased uncertainty and risk in the operational and financial decisions related to procurement. Providers must seek optimal ways to deliver the required volume of power to retailers and end users while managing risk. We consider a mixed-integer programming model for a power providing agent that jointly considers the problem of selecting custom electricity contracts and finding the optimal procurement strategy of meeting contract obligations under spot price uncertainty. A two-stage stochastic integer programming (SIP) model with a conditional value-at-risk (CVaR) constraint to incorporate risk aversion is developed. Computational results are presented that demonstrates the CVaR approach and the results are compared with a corresponding expected cost minimization approach. The SIP model with CVaR will allow acceptance of contracts at lower prices compared to an approach based on a corresponding risk-neutral model as a hedge against uncertainty and mis-specified arbitrage.     

DESIGNING A MARKET STRUCTURE WHEN FIRMS COMPETE FOR THE RIGHT TO SERVE THE MARKET*

In many industries, a regulator designs an auction to select ex‐ante the firms that compete ex‐post on the product market. This paper considers the optimal market structure when firms incur sunk costs before entering the market and when the government is not able to regulate firms in the market. We prove that a free entry equilibrium results in an excessive entry when the entry costs are private information. Then, we consider an auction mechanism selecting the firms allowed to serve the market and show that the optimal number of licences results in the socially optimal market structure. When all the potential candidates are actual bidders, the optimal number of firms in the market increases with the number of candidates and decreases with the social cost of public funds. When the market size is small, as the net profit in the market decreases with the number of selected firms, entry is endogenous. As increasing competition in the market reduces competition for the market, the optimal structure is more concentrated than in the previous case.     

A dynamic policy license for flexible spectrum management

Electromagnetic spectrum for wireless communications is fully allocated by regulatory authorities, but this does not mean that it is fully utilized. Demand for greater capacity and new services requires new regulatory and technical models for spectrum sharing. This paper develops a regulatory model denoted the dynamic policy license. The dynamic policy license combines the assurances to licensees that come from holding a fixed license while maintaining regulatory flexibility. A dynamic policy license is similar to a traditional spectrum license that specifies a bandwidth, power, center frequency, location, and other parameters. However, one or more of these parameters is subject to change by the regulator over time. The allowed changes are restricted by the license to provide assurances and predictability to the licensee. The opportunities and challenges that this presents to both regulators and licensees is described. For instance, the dynamic policy license can be a regulatory tool for more aggressive spectrum sharing.     

基于双通道接收的干扰对消性能分析

为了探究在工程实现中卫星通信地球站使用干扰对消抵抗来自空中平台或周边干扰的可行性,对不同接收环境下的干扰对消性能进行了分析。首先,在假定2个通道中干扰差异被准确估计并补偿的情况下,推导出理论性能的近似计算公式;然后,采用最小均方(least mean square, LMS)自适应滤波器对2个通道干扰的差异进行补偿,完成干扰对消;最后,通过仿真实验对使用LMS自适应滤波器的干扰对消进行验证。结果表明：干扰对消的理论性能在卫星信号与干扰入射夹角大于15°时信噪比恶化可以接近0 dB,而夹角小于15°时信噪比恶化程度明显提高;除了入射夹角的影响外,采用LMS自适应滤波器的干扰对消性能还受算法参数、干扰大小等其他因素的影响,对于固定频点的干扰,在入射夹角大于4°且主通道干信比小于30 dB时,干扰对消后信噪比恶化小于0.6 dB,而且这一结果基本不受采样率的影响。所提出的理论性能近似计算公式可以为干扰对消算法的性能评价提供参考,采用LMS自适应滤波器的干扰对消在算法参数设置合理的情况下可以接近理论性能。     

Wi-Fi as a Commercial Service: New Technology and Policy Implications

While Wi-Fi has enjoyed explosive growth and deployment for use in residential homes, the rollout of commercial Wi-Fi service has been more limited. Part of the holdback on large-scale commercial deployment has been the strategic concern that the commons model to spectrum management lacks the incentives for service providers to invest due to the limited ability to manage interference in the unlicensed band. Today, however, this situation appears to have changed. To explain the new confidence by service providers in commercial Wi-Fi, the activities of the Wi-Fi Alliance and IEEE 802.11 standards body are analyzed to show how these groups essentially replicate many, but not all, of the functions traditionally employed by an effective band manager that is optimizing efficiency on a licensed spectrum block more typically associated with the deployment of commercial services. Consequently, with the Wi-Fi ecosystem functioning as an effective spectrum manager, it is concluded that the service provider investment in Public Wi-Fi networks is rational and the risk posed by saturation or overuse has been reduced to an acceptable level. The strategic implications of this finding on the Wi-Fi platform are the examined. How the requirements from service providers are already significantly influencing the evolution of the Wi-Fi standard is discussed, and an attempt is made to address the risks and liabilities associated with the unlicensed spectrum management model. Thus, service providers increasingly need functionality in Wi-Fi technology to manage interference, and monitor and improve network performance. The current ideas under discussion are elaborated for the next version of Wi-Fi to support both commercial Wi-Fi requirements, which address the interference concerns, but only up to a point, as the unlicensed model intrinsically leaves some risk to participants of spectrum saturation through overuse.     

慎重看待大用户直供电问题

论述了在电力市场初期我国缺少实施大用户直供电所必须具备的若干条件,分析了当前开展大用户直供电存在的问题及可能造成的影响,指出开展直供是改革的趋势但不可急于求成.     

The unfinished history of usage rights for spectrum

The key task in the next stage of spectrum management is to adapt regulation to the prospect of widespread sharing, on a much more sophisticated basis than sharing is used today. There is a role for the regulator to take steps to expand the area of choice within which public and private sector users can operate. This is best done in general by enhancing the flexibility of usage rights, which itself is best achieved by enhancing the freedom to trade them in the dimensions of time, space, level of interference and priority of access, by subdividing, re-aggregating, etc. However, there are considerable transactions cost impediments to trading where unlicensed users are involved. This creates a role for the regulator pro-actively to investigate different allocations, to make provisions for the most promising to occur and to incorporate both in refarming exercises and in primary assignments based on auctions configurations of usage rights, which might favour promising avenues of shared spectrum use.