The Dynamic Spectrum Alliance, a group backing more flexible, affordable, access to spectrum, just concluded its Global Summitin Accra. The group includes Internet Heavyweights such as Facebook, Google and Microsoft, who are keen to explore ways of extending broadband Internet to the 3 billion+ who currently lack the education, healthcare and economic benefits it can bring. Bridging this digital divide was a central theme of the Summit, building on discussion stimulated by the CEO of Facebook and others at the Mobile World Congress (MWC), back in March 2014. Whilst the challenge at MWC was to operators to make mobile broadband more affordable, the challenge at the DSA Summit was to regulators (and industry) to enable low cost coverage solutions (especially using TV white spaces) which in turn would allow connectivity costs to be lowered to the point of affordability even in rural areas. The figure of $2/month emerged as the target level, which would allow rural communities to bootstrap their economic development.

Former Ofcom Spectrum Chief Prof H Nwana, is the new Chief Executive of the DSA, who guided the event programme and discussion towards its successful conclusion. The programme was sufficiently engaging to keep a good attendance right through to the end, in spite of the somewhat higher frequencies (UV) available in abundance to those reclining on the nearby Labadi Beach.

An African poverb was introduced 'If you want to go further, then travel together'. This seemed an appropriate encouragement for regulators and industry who want to make DSA a reality in their country. Delegates heard about numerous and diverse partnerships around the world, which have delivered real benefits.

News from technology vendors on their plans for silicon, and hence more compact and affordable devices, was encouraging for regulators and operators who would like to see DSA-based networks able to operate commercially - standealone or with part subsidy. The fact that TV white spaces (TVWS) is now a commercial reality in the US and imminently in the UK, has encouraged vendors to invest in their product development - both in radios and database services.

The event in Accra was co-hosted by the Ghanaian regulator (NCA) and there were regulators as well as academic and industry representatives from a number of other African countries - as well as from Europea, America and Asia. The host regulator seemed proud to announce the latest TV white spaces pilot, in Ghana, backed by Microsoft, Facebook and SpectraWireless (an African company with a strong interest in extending Internet connectivity across this continent). Delegates at the summit enjoyed Wi-Fi service (called Djungle), whose backhaul used white space links which have just been installed.

Costs of backhaul are still a big issue for rural areas, but Don Means from Gigabit Libraries presented groundbreaking work by his organisation on using TVWS technology to distribute connectivity around public buildings such as libraries.This is helping libraries to reinvent themselves at the heart of local communities.

Representatives from the ITU and GSMA emphasised the need for interference protection to underpin mobile broadband investments and seemed not quite so keen on expanding licence exempt access.

Related to this topic was a discussion of whether DSA frameworks should offer white space channel reservations (sometimes referred to as a protected mode or safe harbour), to provide certainty to those (small or large operators) wishing to deploy wide area networks using this technology. Effectively, the US and UK (draft) regulatory frameworks already offer a protected mode, for professional PMSE applications (wireless microphones etc.).

There was a debate about whether exclusivity was the best way of 'guaranteeing' spectrum access, given the success of licence exempt Wi-Fi and increasing sophisticated use of MIMO etc to create separate channels and avoid the waste of capacity that can accompany exclusivity.

Many supported the use of DSA to enable an increase in licence-exempt allocation, especially below 1 GHz - with the clear importance of this spectrum region for filling gaps in broadband coverage - large and small. Against a backdrop of reductions in UHF capacity allocated to broadcasting, there were strong arguments for creating a licence exempt reserve - effectively a minimum capacity that would be available everywhere for Super Wi-Fi (using the new IEEE 802.11af standard, which binds TV white spaces into the future of Wi-Fi.

Larkhill was delighted to meet with representatives from African regulators, ISPs and academics. It seems clear to us that Africa's role in shaping spectrum policy is continuing its ascendancy. Although DSA may have seemed a somewhat dry and complex technical subject, this Summit has assisted the raising of awareness of its great potential to help bring Internet to the 70% of Africans who live outside urban centres - without displacing existing wireless services , including TV broadcasting.

It was encouraging to see a wide range of TVWS pilots/trials underway in different African countries. Microsoft and Google have helped local players to get the networks up and running in a number of cases. The Centre for White Space Communications (University of Strathclyde) has brought its unique rural connection expertise to bear in helping with many of these roll-outs, under the Project Mawingu (Cloud) umbrella.

The various pilots use diverse configurations, but the common factors include long link lengths, some non-line of sight requirements and generally abundant white space channels. It is easy to see why the TV white spaces technology is attracting so much attention in Africa.

At the end of July 2014, the Glasgow 2014 Commonwealth Games will bring many of the interested African countries to a city which itself is playing host to a significant TV white space deployment (as part of Ofcom's UK TVWS pilot) and is the home of the Centre for White Space Communications. It should be a great opportunity to continue the discussions.

Watch these spaces....

Further reading:

African Telecom and IT

Telecom TV

Over the two days, delegates were

The World WiFi and Small Cell Summit , 28th-29th October 2014 in Barcelona, attracted industry representatives from across the globe, focussing on technology advances that will enable operators to service the growing demands for mobile connectivity.

There were two strands to the proceedings – Wi-Fi and Small Cells. Originally there had also been plans for a Cloud Radio Access Network (CRAN) strand, but it had been contracted and interwoven with the other strands.

Given that many of the target audience were service providers, it was not surprising that there was much in common between the Wi-Fi and Small Cell strands. The emphasis on needing to ‘densify’ coverage was shared – with Wi-Fi as the ideal for maximising capacity, given the high degree of spectrum use. Coverage in buildings was also an issue, where again Wi-Fi has much to offer. There is an increasing interest in managing Wi-Fi and integrating it into service platforms, alongside licensed network technologies. Other themes included:

• Centralisation of base station functionality – whether for small cells or macro cells, using either fibre or high capacity wireless front haul technologies to link antennas to a central hub. The central hub could be cloud-based ultimately with functionality being provided scalably via software. This offers operating cost savings, yields more efficient coverage and is more flexible to adapt to rapidly evolving market requirements

• Aggregration of bands to increase throughtput - even across traditional licenced /licence-exempt boundaries. Thus Wi-Fi cellular hybrids start to appear in the picture, with integration in the service platform rather than in end-user client devices.

Larkhill’s contribution to the event was a presentation on the opportunity of using dynamic spectrum access technology to use spectrum more efficiently, with TV white spaces providing a global opportunity to create a really powerful extension to Wi-Fi. We also highlighted the need to address resiliency, ad-hoc flexibility and coverage – as well as the growing capacity requirements for mobile access networks. You can see a summary of our presentation here.

With TV white spaces having been given the green light to become a real commercial proposition in the UK this year - with many other countries at different stages of their regulatory journey, the technology may soon start to be incorporated in a range of consumer as well as professional devices.

Our founder, Andrew Stirling, was quoted in a recent article in Videonet by digital broadcasting columnist Barry Flynn, discussing the prospects for TV white spaces coming to a TV set near you. After all the UHF bands which are home to TV white spaces are already well catered for in terrestrial TV receivers and antenna systems.

Ofcom has just announced that it is proceeding with the opening of licence exempt access to the TV white spaces.This is a landmark decision, opening the door to a new era in more flexible access to spectrum. It complements the forms of spectrum access, largely licensed, by exploiting new dynamic spectrum access (DSA) technology

DSA allows unused spectrum capacity to be identified e.g. through a national database of available channels in each area. This means that devices which need to form a link can do so without disrupting established services and applications. In the case of TV white spaces, the established uses include Digital Terrestrial Television (the primary spectrum user) and wireless microphones (and related equipment, referred to as 'Programme Making and Special Events' (PMSE) devices)

DSA enables spectrum to be used more efficiently, by allowing opportunistic access to unused pockets of capacity - e.g. in rural areas. Users or communities can purchase their own equipment to take advantage of this spectrum - e.g. to fill holes in broadband coverage, complementing service availability from national operators, for example.

After working with industry over a number of years and learning from the FCC experience, Ofcom developed a frameowrk for using the TV white spaces. It has been conducting a Pilot of this framework since 2013, in which a number of projects from across the UK have been taking part. Scotland has seen a number of interesting deployments - starting with the first UK TVWS trial network , back in 2011, then with the University of Strathclyde's city centre campus deployment (Glasgow) and more recently the pilot network aimed at bringing Wi-Fi to Orkney ferries. Ofcom's release lists these together with an appealing zoo animal watch application provided by Google and a flood detection network in Oxford - with LoveHz and Nominet cooperating.

Members of Regulatory Affairs group of the Dynamic Spectrum Alliance (DSA) have been putting their heads together to review regulatory practice across the world, on access to the TV white spaces and have assembled a Model set of rules. Most of the development work on regulations has been undertaken by the FCC and Ofcom (UK), working with industry.

The intention is to help administrations which have not yet investigated introduction of TV white spaces technology to get up the learning curve faster. The documents provided on the DSA website include:

1. The Model Rules backgrounder introduces the significance of access to the TV white spaces and the key components of the sharing mechanism designed to protect existing users of the band, namely terrestrial TV viewers and wireless microphone users

2. Suggested Technical Rules and Regulations for the Use of Television White Spaces

3. Frequently Asked Questions 

The model rules are based around the use of geolocation databases, with white space devices reporting their positioning in order to determine what spectrum is available to use. They include the concept of master and client devices, where the master device acts an intermediary between client devices and databases. Clients need only consult their local master device in order to determine which channels are safe to use.