E-band Wireless Comms: UK Announces New Approach

On Dec. 16 2013, Ofcom—the UK telecom regulator—announced a new approach for the use of E-band wireless communications in the United Kingdom. This new approach results from an earlier Ofcom consultation exercise in which Aviat Networks participated.

To summarize, the new approach, which is available for licensing after Dec. 17, 2013, splits the band into two segments. Ofcom will coordinate the lower segment of 2GHz, while the upper segment of 2.5GHz will remain self-coordinated as per the prior policy.

The segment Ofcom coordinates will follow the usual regulatory processes for all the other fixed link bands it oversees. Moreover, Ofcom has already updated all the relevant documents and forms to accommodate E-band. While we (i.e., Aviat Networks, other telecom vendors) would have preferred the larger portion of spectrum to have been granted to the Ofcom-coordinated process, we welcome this new arrangement because it provides an option for greater security and peace of mind to operators in terms of protection from interference than was envisaged for the previous all self-coordinated spectrum regime.

For a more detailed look at the new E-band arrangement, Figure 1 shows the Ofcom-coordinated section sitting in the lower half of both the 71-76GHz and 81-86GHz bands thus allowing for the deployment of FDD systems in line with ECC/REC(05)07.

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Figure 1: Segmented Plan for Mixed Management Approach (click on figures to enlarge)

In terms of channelization within the Ofcom-coordinated block, the regulator announced that it would permit 8 x 250MHz channels, 4 x 500MHz channels, 1 x 750MHz channel and 1 x 1000MHz channel as per ECC/REC(05)07. Ofcom also stated that 62.5MHz and 125MHz channels will be implemented as soon as the relevant technical standards, etc., from ETSI are published. Figure 2 shows the Ofcom channel plan:

Figure-2-Ofcom-Permitted-E-band-Channelizations-Aviat-Networks-blog-on-Ofcom-E-band-policies-18Dec13

Figure 2: Ofcom Permitted E-band Channelizations

Regarding equipment requirements, Ofcom stated that it will allow equipment that meets the appropriate sections of EN 302 217-2-2 and EN 302 217-4-2. This includes the antenna classes (e.g., classes 2-4) that will allow the deployment of solutions with flat panel antennas. Aviat Networks welcomes this approach and hopes that other regulators—notably the FCC in terms of antenna requirements—currently considering opening up and/or revising their rules for E-band adopt similar approaches.

The license fees for the self-coordinated segment remains at £50 per link per annum, whereas in the Ofcom-coordinated segment the fees are bandwidth based as reflected in Figure 3:

Figure 3-Ofcom-Bandwidth-based-Fees-Aviat-Networks-blog-on-Ofcom-E-band-policies-18Dec13

Figure 3: Ofcom Bandwidth-based Fees

Notwithstanding the current fees consultation process that Ofcom is undertaking, these “interim fees” will remain in place for five years, after which time the results of the fees review may mean that they will be amended.

Also because of responses received during the consultation process, within the self-coordinated block, Ofcom will now require the following additional information for the self-coordination database: antenna polarization (horizontal, vertical or dual), ETSI Spectrum Efficiency Class and whether the link is TDD or FDD.

Ian Marshall
Regulatory Manager
Aviat Networks

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Should National Telecom Regulators Impose Buildout Requirements on Operators?

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Photo credit: fingle / Foter / CC BY-NC-SA

In the mobile operator space in many countries, the national regulators are imposing so-called “buildout requirements” as a license condition on many wireless providers. In some countries, these requirements are restricted to licenses awarded by the auction process (e.g., cellular access spectrum) or block allocations while in others these conditions are attached to the majority of licenses.

Where buildout requirements are employed, a license typically has a clause that requires the licensee to build out a network/link or specified portion of a network within a certain period of time, with penalties imposed for failure to do so.

The rationale behind imposing these requirements is to ensure that after spectrum is assigned it is put to its intended use without delay. By doing this, or so the theory goes, bidders are discouraged from acquiring spectrum with the sole intent of blocking competitors’ activities without themselves offering service. Of course, the ultimate goal is the protection of spectrum—a finite and precious resource. There is no reason buildout requirements cannot be attached to any license grant, assuming that the detail of the requirements recognizes any constraints of the application for which the spectrum is sought.

Nevertheless, Aviat Networks is strongly against auctions and block allocations, but where these are a necessity then buildout requirements must be part of any award, with strong enforcement rules. The problem is that with strong enforcement operators and regulators can be at loggerheads and get tied up in court with lawsuits and countersuits for years. For example, in the U.S. you have the case of Fibertower. The FCC claims that Fibertower deliberately underbuilt its network and so moved to revoke its spectrum licenses. With the regulator moving against the operator, it came under insurmountable financial pressure and filed for bankruptcy. But even now, the operator’s creditors are fighting the FCC in order to recoup frequencies valued at more than US$100 million. So it is questionable whether this actually works in practice.

Microwave is the point
Focusing on point-to-point microwave, let’s examine the approach taken in two different countries. In the United States, for traditional link-by-link allocation, the FCC imposes an 18-month deadline by which time the link in question needs to be in service. However, in the United Kingdom, Ofcom imposes no such deadline. For certain applications, certain routes and sites are critical and can quickly become “full.” If these key locations are being filled by license applications that are not being translated into operational services, then this spectrum is effectively wasted as no one else can use it, nor is there any service being offered. Spectrum wasted in this manner reduces overall spectrum efficiency, and all spectrum authorities are motivated to ensure that spectrum is used in the most efficient way possible.

Of course having these rules is fine, but what happens when the rules are breached? In some cases, an operator will apply for an extension prior to the expiration of the original deadline; this may or may not be granted. However, the real test is what happens when the deadline passes. Ideally, what should happen is that the license(s) in question would be revoked and the associated spectrum made available for reallocation. Furthermore, if the spectrum in question was originally made available by block allocation or auction, then again, ideally, this spectrum should be returned to the pool of spectrum available for link-by-link licensing.

Additionally in shared bands, i.e., spectrum shared by the Fixed Service (FS) and the Fixed Satellite Service (FSS) should be governed by the same requirements in this instance. Therefore, unused/defunct FSS allocations/licenses should also be revoked with the spectrum being made available for reuse. In the case of FSS locations, this can have a significant effect owing to the geographic full-arc protection area that is usually associated with earth stations.

Counterpoint
The alternative viewpoint is that the current buildout requirements are counterproductive, in their aim to foster efficient use of spectrum. One reason cited for this view is that it takes time for an equipment supply ecosystem to develop, which will serve the spectrum users. However, when we examine this claim more carefully, it seems that this is often used where the spectrum has been awarded to a single user either by block allocation or by auction. We have written before about how auctions and block allocations are unsuitable for point-to-point microwave, and the claim above is a direct result of this process, which negatively impacts the number of operators. In turn, that reduces the ranks of equipment vendors, leading to thinner competition and, therefore, decreased incentive for innovation. This situation is made worse if the operator in question chooses a band plan that is nonstandard in terms of either existing U.S. or international arrangements.

Signal termination
In the final analysis, it does not serve any stakeholders’ goals to have valuable spectrum allocated but unutilized. Thus, having buildout requirements would appear to be a good idea. But along with that, an effective mechanism for reclaiming and making available to others spectrum that runs afoul of these rules is paramount to making the process work for the Greater Good. In Aviat’s view, buildout requirements are a valuable tool in ensuring spectrum efficiency and as such, their use should be seriously considered in all countries.

Ian Marshall
Regulatory Manager
Aviat Networks

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TDD or FDD Wireless: That is the Question!

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TDD, or Time Division Duplex, where a single radio channel is used to send and receive data, has been a common technique employed in unlicensed microwave transmission bands, such as 2.4 and 5.8GHz. The advantage of TDD is a simplified and lower cost design, often based upon 802.11 standards. In contrast, FDD, or Frequency Division Duplex, where data is transmitted in one frequency channel and received in another (separated by anywhere from less than 100 to more than 1,000 MHz) has been the staple of licensed frequency bands between 2 and 38 GHz worldwide.

Now, a number of the CEPT recommendations for the new point to point bands over 40GHz contain provisions for TDD operation. TDD is accommodated either as an alternative band plan or a mixed TDD/FDD band plan, in addition to the more common FDD band plan. However, CEPT recommendations are only just that—recommendations. How these bands will be implemented in each country will be determined by the individual national regulatory authority.

Recently, we asked a number of European national regulators about if and how they would introduce TDD operation in these new bands. The general response was that they were not opposed to the introduction of TDD in principle, and that such operation would have to be worked into existing or revised band plans. One complication raised was that spectrum would have to be reserved for guard bands between TDD and FDD segments within the same band. Regulators usually try to avoid having to waste valuable spectrum in this way. Also, once a band plan is established and the spectrum allocated to users, efforts to introduce TDD operation at a later date is extremely difficult.

Some regulators have already issued new national band plans at 42GHz and above, and to date none of these allow for TDD operation. Furthermore, for countries that have allocated new bands through spectrum auction, there we see the usual FDD style symmetric band approach.

Despite the appeal of TDD operation from a cost perspective, early indications are that although provision for TDD operation is being made in these higher bands, practical complications and concerns over maximizing the use of new bands may prevent its widespread introduction.

What are your thoughts on using TDD more in national band plans? Leave a comment, if you’d please.

Ian Marshall
Regulatory Manager, Aviat Networks

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