Challenges in the future 'Network of Networks'

Came across this paper from Dec. 2000 recently. Its interesting to see that even back then researchers were thinking about multiple networks that a user can have access to via handovers. Researchers nowadays think about how to access as many networks as possible simultaneously. I call is Multi-stream aggregation (MSA), some others call it Multi-RAT Carrier Aggregation (MCA) and so on.

If we look at the different access technologies, each has its own evolution in the coming years. Some of these are:

• Fixed/Terrestrial broadband: (A)DSL, Cable, Fiber
• Mobile Broadband: 3G, 4G and soon 5G
• Wireless Broadband: WiFi
• Laser communications
• LiFi or LED based communications
• High frequency sound based communications 

Then there could be a combination of multiple technologies working simultaneously. For example:

• Broadband Access via Integrated Terrestrial & Satellite Systems (BATS)
• LTE-U / LTE-LAA

And the handover has to be seamless between different access technologies. For example:

• Seamless handovers between cellular and WiFi and vice versa.

There has been an interest in moving on to higher frequencies. These bands can be used for access as well as backhaul. The same applies for most of the access technologies listed above which can work as a backhaul to enable other access technologies.

While planned networks would be commonplace, other topologies like mesh network will gain ground too. Device to device and direct communications will help create ad-hoc networks.

While the current networks are mostly stationary, mobile networks will also become common. Opportunity Driven Multiple Access (ODMA) or Multihop Cellular Networks (MCN) would help devices use other devices to reach their destination. Non-standardised proprietary solutions (for example Firechat) will become common too. Security, Privacy and Trust will play an important role here.

Satellite networks, the truly global connectivity providers will play an important role too. While backhauling the small cells on planes, trains and ships will be an important part of satellite networks, they may be used for access too. Oneweb plans to launch 900 micro satellites to provide high speed global connectivity. While communications at such high frequencies mean that small form factor devices like mobile cant receive the signals easily, connected cars could use the satellite connectivity very well.

Samsung has an idea to provide connectivity through 4,600 satellites to be able to transmit 200GB monthly to 5 Billion people worldwide. While this is very ambitious, its not the only innovative and challenging idea. I am sure we all now about the Google loon. Facebook on the other hand wants to use a solar powered drone (UAV) to offer free internet access services to users who cannot get online.

As I mentioned, security and privacy will be a big challenge for devices being able to connect to multiple access networks and other devices. An often overlooked challenge is the timing and sync between different networks. In an ideal world all these networks would be phase and time synchronised to each other so as not to cause interference but in reality this will be a challenging task, especially with ad-hoc and moing networks.



I will be giving a keynote at the ITSF 2015 in November at Edinburgh. This is a different type of conference that looks at Time and Synchronisation aspects in Telecoms. While I will be providing a generic overview on where the technologies are moving (continuing from my presentation in Phase ready conference), I am looking forward to hearing about these challenges and their solutions in this conference.

Andy Sutton (Principal Network Architect) and Martin Kingston (Principal Designer) with EE have shared some of their thought on this topic which is as follows and available to download here.

Broadband Access via Integrated Terrestrial & Satellite Systems

Last week I attended an event in the University of Surrey that was about providing high speed connectivity to un-served and under-served areas in future. While there is no arguing that satellites are a great option for unserved areas, the underserved areas can really benefit by such initiatives.

The way this is being proposed is to have a specialised Intelligent User Gateway (IUG) that can connect to ADSL, Mobile and Satellite. The assumption is that in areas of poor conectivity, ADSL can provide 2Mbps and the mobile could do something similar, upto 8Mbps. The satellites can easily do 20Mbps.

Evolution path of Satellite Broadband: 2005: 2 - 3Mbps 2010: 10 - 20 Mbps 2015: 30 - 30 Mbps 2020: roughly 100 Mbps

— Zahid Ghadialy (@zahidtg) June 11, 2015

While the satellite broadband has the advantage of high speeds, they often suffer from high latencies. ADSL on the other hand has very small latency but may not be good enough for streaming kind of applications. Mobile generally falls in between for latency and speed. Using Multipath TCP and some intelligent routing algorithms, decisions can be taken to optimise for latency and speeds.

I did see some impressive demo's in the lab and it did what is says on the tin. The real challenge would be the business models. While ADSL can offer unlimited internet, both Mobile and Satellite broadband will have caps. I was told that limits could be imposed so that once the Mobile/Satellite data allowance is over, only ADSL would be used. Maybe a more complex algorithm could be implemented in future that can include cost and priority of the application/service being used.

An example would be that sometimes I want to watch some long videos over Youtube but I am happy to start buffering an hour in advance. Its not critical that I have to watch that now. I would be more than happy to save my Mobile/Satellite broadband data allowance for some other day when I need to watch things more urgently. If the end of month is coming and I have a lot of data allowance left then maybe I dont mind using the quota otherwise I will anyway lose the allowance. Its always challenging to put this intelligence in the routing decision algorithms though.

Anyway, the combined presentations are embedded below and you can download them from the BATS project page here:

BATS Dissemination Day at University of Surrey - June 2015 from Zahid Ghadialy

Smart Homes of the Future and Technologies

Saw the above picture recently on Twitter. While its great to see how connected our future homes and even cities would be, it would be interesting to see what technologies are used for connecting these devices.

Cambridge Wireless had a smart homes event last month, there were some interesting presentations that I have detailed below.

The first of these technologies discussed is LoRa. As can be seen, its billed as ultimate long range (10 mile) and low power (10 year battery lifetime) technology. It uses spread-spectrum making it robust to channel noise. Here is the presentation:

The next technology is Zigbee 3.0. According to Zigbee Alliance:

The new standard unifies ZigBee standards found in tens of millions of devices delivering benefits to consumers today. The ZigBee 3.0 standard enables communication and interoperability among devices for home automation, connected lighting, energy efficiency and other markets so more diverse, fully interoperable solutions can be delivered by product developers and service providers. All device types, commands, and functionality defined in current ZigBee PRO-based standards are available to developers in the new standard.

ZigBee 3.0 defines the widest range of device types including home automation, lighting, energy management, smart appliance, security, sensors, and health care monitoring products. It supports both easy-to-use DIY installations as well as professionally installed systems. Based on IEEE 802.15.4, which operates at 2.4 GHz (a frequency available for use around the world), ZigBee 3.0 uses ZigBee PRO networking to enable reliable communication in the smallest, lowest-power devices. Current ZigBee Certified products based on ZigBee Home Automation and ZigBee Light Link are interoperable with ZigBee 3.0. A complete list of standards that have been merged to create ZigBee 3.0 can be seen on the website at www.ZigBee.org.

“The ZigBee Alliance has always believed that true interoperability comes from standardization at all levels of the network, especially the application level which most closely touches the user,” said Tobin J. M. Richardson, President and CEO of the ZigBee Alliance. “Lessons learned by Alliance members when taking products to market around the world have allowed us to unify our application standards into a single standard. ZigBee 3.0 will allow product developers to take advantage of ZigBee’s unique features such as mesh networking and Green Power to deliver highly reliable, secure, low-power, low-cost solutions to any market.”

ZigBee (3.0): Global Standard for IoT from Zahid Ghadialy

Finally, we have Bluetooth Smart mesh.

CSRmesh enables Bluetooth® low energy devices not only to receive and act upon messages, but also to repeat those messages to surrounding devices thus extending the range of Bluetooth Smart and turning it into a mesh network for the Internet of Things.

Bluetooth Smart Mesh for the Smart Home from Zahid Ghadialy

While the CW event was not able to discuss all possible technologies (and believe me there are loads of them), there are other popular contenders. Cellular IoT (CIoT) is one if them. I have blogged about the LTE Cat-0 here and 5G here.

A new IEEE Wi-Fi standard 802.11ah using the 900MHz band has been in works and will solve the need of connectivity for a large number of things over long distances. A typical 802.11ah access point could associate more than 8,000 devices within a range of 1 km, making it ideal for areas with a high concentration of things. The Wi-Fi Alliance is committed to getting this standard ratified soon. With this, Wi-Fi has the potential to become a ubiquitous standard for IoT. See also this article by Frank Rayal on this topic.

Finally, there is SIGFOX. According to their website:

SIGFOX uses a UNB (Ultra Narrow Band) based radio technology to connect devices to its global network. The use of UNB is key to providing a scalable, high-capacity network, with very low energy consumption, while maintaining a simple and easy to rollout star-based cell infrastructure.

The network operates in the globally available ISM bands (license-free frequency bands) and co-exists in these frequencies with other radio technologies, but without any risk of collisions or capacity problems. SIGFOX currently uses the most popular European ISM band on 868MHz (as defined by ETSI and CEPT) as well as the 902MHz in the USA (as defined by the FCC), depending on specific regional regulations.

Communication on SIGFOX is secured in many ways, including anti-replay, message scrambling, sequencing, etc. The most important aspect of transmission security is however that only the device vendors understand the actual data exchanged between the device and the IT systems. SIGFOX only acts as a transport channel, pushing the data towards the customer's IT system.

An important advantage provided by the use of the narrow band technology is the flexibility it offers in terms of antenna design. On the network infrastructure end it allows the use of small and simple antennas, but more importantly, it allows devices to use inexpensive and easily customizable antennas.

Sigfox is also working on project Mustang, a three-year effort to build a hybrid satellite/terrestrial IoT (internet of things) network. According to Rethink Research:

The all-French group also contains aerospace firm Airbus, research institute CEA-Leti and engineering business Sysmeca. The idea is to use Sigfox as the terrestrial data link, with satellite backhaul and connections to planes and boats provided by a low-earth orbit (LEO) satellite constellation.
...
The satellite link could be added to either the end devices or the base station, so that if a device was unable to connect to the terrestrial Sigfox network, it could fall back to the satellite.

While the power requirements for this would be prohibitive for ultra-low power, battery-operated devices, for those with a wired power supply and critical availability requirements (such as smart meters, alarms, oil tankers and rigs) the redundancy would be an asset. These devices may transmit small amounts of data but when they do need to communicate, the signal must be assured.

The Sigfox base station could be fitted with a satellite uplink as a primary uplink as well as a redundancy measure in some scenarios where terrestrial network reach cannot be achieved. With a three-year lifecycle, Mustang’s participants are looking to create a seamless global network, and note that the planned dual-mode terrestrial/satellite terminal will enable switching between the two channels in response to resource availability.

The group says that the development of this terminal modem chipset is a priority, with later optimization of the communication protocols being the next step before an application demonstration using an airplane.

The project adds that the full potential of the IoT can only be achieved by offering affordable mobile communications at a global scale and reach. Key to this is adapting existing networks, according to the group, which explains why Sigfox has been chosen – given that the company stresses the affordability of its system.

Well, there are a lots of options available. We just have to wait and see which ones work in what scenarios.

Report on Spectrum Usage and Demand in the UK

Last week at work, we released a report titled "UK Spectrum Usage & Demand". The only time most people hear about spectrum is when there are some auctions going on. Often a small chunk of spectrum gets sold off for billion(s) of dollars/pounds and these surely make a headline. As I recently found out, 50% of spectrum in UK is shared and 25% is license exempt.

Anyway, this first edition of the report focuses on Public Mobile, Utilities, Business Radio and Space/Satellites. Space is becoming an important area of focus here as it is a significant contributor to the UK economy.

Anyway, the report is embedded below and is available to download from here:

Air-Ground-Air communications in Mission Critical scenarios

In-flight communications have always fascinated me. While earlier the only possibility was to use Satellites, a hot topic for in the last few years has been Air-Ground-Air communications.

Some of you may remember that couple of years back Ericsson showed an example of using LTE in extreme conditions. The video below shows that LTE can work in these scenarios.



Now there are various acronyms being used for these type of communications but the one most commonly used is Direct-Air-to-Ground Communications (DA2GC), Air-to-Ground (A2G) and Ground-to-Air (G2A).

While for short distance communications, LTE or any cellular technology (see my post on Flying Small Cells) may be a good option, a complete solution including communication over sea would require satellite connectivity as well. As I have mentioned in a blog post before, 75Mbps connectivity would soon be possible with satellites.

For those interested in working of the Air-Ground-Air communications, would find the presentation below useful. A much detailed ECC CEPT report from last year is available here.

Direct Air-to-Ground Communication – Broadband for Planes from Zahid Ghadialy

The next challenge is to explore whether LTE can be used for Mission Critical Air Ground Air communications. 3GPP TSG RAN recently conducted study on the feasibility and the conclusions are as follows:

There is a common understanding from companies interested in the topic that:

1. Air-to-Ground communications can be provided using the LTE standards (rel-8 and beyond depending on the targeted scenarios).
2. 3GPP UE RF requirements might need to be adapted
3. It may be possible to enhance the performance of the communications with some standards changes, but these are in most cases expected to be non-fundamental optimizations
4. Engineering and implementation adaptations are required depending on the deployment scenario. In particular, the ECC report [1] comments that from implementation point of view synchronization algorithms are to be modified compared to terrestrial mobile radio usage in order to cope with high Doppler frequency shift of the targeted scenario. In addition, some network management adaptations might be needed. From engineering perspective the Ground base station antenna adjustment has to be matched to cover indicated aircraft heights above ground up to 12 km by antenna up-tilt. It is also expected that the inter-site distances would be dominated by the altitudes to be supported [5].
5. A2G technology using legacy LTE has been studied and successfully trialed covering different kinds of services: Surfing, downloading, e-mail transmission, use of Skype video, audio applications and Video conferencing. Related results can be found in several documents from ECC and from companies [1], [2], [3]. The trials in [1] and [2] assumed in general a dedicated spectrum, and the fact that the communications in the aircraft cabin are using WIFI or GSMOBA standards, while LTE is used for the Broadband Direct-Air-to-Ground connection between the Aircraft station and the Ground base station.
6. It is understood that it is possible to operate A2G communications over spectrum that is shared with ground communications. However, due to interference it is expected that the ground communications would suffer from capacity losses depending on the deployment scenario. Therefore, it is recommended to operate A2G communication over a dedicated spectrum.
7. It can be noted that ETSI studies concluded that Spectrum above 6 GHz is not appropriate for such applications [4].
8. LTE already provides solutions to allow seamless mobility in between cells. Cells can be intended for terrestrial UEs and cells intended for A2G UEs which might operate in different frequencies.
9. Cell range in LTE is limited by the maximum timing advance (around 100km). Larger ranges could be made possible by means of implementation adaptations. 

In-flight broadband connectivity service with speeds up to 75Mbps

Came across the following Inmarsat press release:

The new network represents two world-beating achievements for Inmarsat and its partners. It will be the world’s first truly hybrid aviation network, consisting of an S-band satellite (Europasat), constructed by Thales Alenia Space, and a Europe-wide S-band ground network. Over the integrated network, based on state-of-the-art LTE technology and access to sufficient spectrum resources, Inmarsat will be offering airlines the world’s fastest in-flight broadband connectivity service with speeds up to 75Mbps, far in excess of the limited capabilities of North American ATG systems.

Alcatel-Lucent and Inmarsat will work together to develop the ground infrastructure component of the new Europe-wide network. Alcatel-Lucent has proven expertise in the development of 4G LTE-based air-to-ground technology and was the world’s first company to field trial this technology in 2011. The initial contract awarded to Alcatel-Lucent will see the global telecommunications equipment company adapting their existing 4G LTE technology to support the S-band spectrum.

Recently Christophe WILHELM, Senior VP Strategy & Innovation, Thales Alenia Space gave a presentation in the Digiworld Summit 2014.

His presentation is above and the video is as follows. Please forward to 1:36:00 to watch his part

Iridium NEXT: Next Generation Satellite Network

Iridium Everywhere

View more presentations from Zahid Ghadialy.

Presented by Dan Mercer, VP & General Manager, EMEA & Russia on November 9th , 2010 at Digital Communications Knowledge Transfer Network And Cambridge Wireless Future Wide Area Wireless SIG – ‘Networks and the New Economy’

To download see: http://www.cambridgewireless.co.uk

Iridium making good progress

It was interesting to see Iridium phones being displayed by Cambridge Consultants in the Cambridge Wireless International Conference. Iridium has gone through some rough times and I remember reading how Satellite communications will change the world but it never came to pass.

Its good to read that the OpenPort terminals are proving effective and can help save lots of money to shipping companies.

Interesting video from Youtube on OpenPort below:

GPS to become commonplace and far more accurate

First it was Nokia that started giving away the Satnav software for free. Now Google is offering free Satnav software for Android phones in UK. Its already been available in US for quite some time and the response is generally positive.

According to comScore, the use cellphones for Satellite Navigation is becoming more common in Europe. According to them, in February, 21.1 million consumers in five large European markets -- Britain, France, Germany, Spain and Italy -- used their cellphones for navigation, 68 percent more than a year ago. This compares to 20.4 million personal navigation devices sold in those markets in 2008 and 2009 in total, according to research firm GfK.

I talked about Satellite based Internet before but today we will focus on satellite based GPS systems.

The GPS system, which was developed way back in 1989 for and by the military has been used by general public since the year 2000. Its has become very common in the last few years.

The GPS we know and love is part of a larger family of systems called Global Navigational Satellite Systems or GNSS. The following are the members of the GNSS; GPS is the USA system, GLONASS is the Russian system, Galileo is the European system and Compass is the Chinese system

The following is from the IET Magazine:

Satellite navigation systems take their location cues from 30 GPS satellites that circle the Earth twice a day transmitting status, date and time, and orbital information. Soon there will be around 100 satellites to lock on to as GPS is joined by global constellations from Europe (Galileo), Russia (GLONASS), and China (Compass).

GPS wasn't built to help us find our way to the shops - it was a Cold War project funded by the US Department of Defense to ensure that nuclear submarines could surface and target their missiles accurately. There are strategic rumblings about the new satellite constellations too, but the current consensus is that civilians have most to gain from more accurate and reliable location and tracking applications. That's if receiver designers can get the power consumption under control.

Russia's GLONASS system used to be famous for its satellites failing faster than they were launched, but since last month it has had 24 functioning satellites in orbit. Meanwhile, Europe's much-delayed Galileo system will have 14 satellites operating by 2014, according to the European Commission, with the full 30 available by 2017. The US GPS system is being modernised to become GPS III by 2013, with additional navigation signals for both civilian and military use. Information about China's Compass system is sketchier - it was going to be a regional system but is now understood to be global.

'All this activity is great news because whatever the application, there will potentially be multiple constellations to get a position fix from, which will help with signal integrity in safety-critical environments such as maritime, aviation or rail, and accuracy for mobile phone users in urban areas,' says Andrew Sage, director of Helios, a consultancy specialising in satellite navigation.

A GPS receiver should be able to 'see' at least four GPS satellites anytime, anywhere on the globe and establish three position coordinates (latitude, longitude, and altitude). But in city streets hemmed in by tall buildings, a receiver is unlikely to be able detect more than two satellites and the signals will often have bounced off structures.

'For the average pedestrian, the position fix can be a long way out and very unpredictable,' says Sage. 'Most users don't see that today because GPS receivers match us to maps and smooth the errors out. But if you are walking around a city and not on a road in a car, multi-path reflections are a problem.'

The more satellites visible from within these 'urban canyons', the easier it is to carry out consistency checks on the received signals. 'Even when you can't isolate the multipath-contaminated signals, the more signals you have, the more your errors average out,' says Dr Paul Groves, lecturer in global navigation satellite systems (GNSS), navigation and location technology at UCL.

Better GNSS integrity would enable new applications, such as road-user charging, enforcing bail conditions and pay-as-you-drive insurance. 'Clearly, if position information might be used as legal evidence, it has to be reliable,' says Groves.

The delayed arrival of Galileo and the resurrection of GLONASS have complicated matters for receiver makers. Galileo was designed to offer the simplest possible upgrade path from GPS to a dual-constellation system. Agreements were made to put the carrier frequencies of the main open services in the same part of the spectrum as GPS, at around 1575MHz, so receivers could share the same radio, analogue components and antenna. Both systems also send their signals using a spread-spectrum code-division multiple-access (CDMA) approach. GLONASS uses a frequency-division multiple-access coding technique (FDMA) and a main open-service carrier frequency of 1602.2MHz.

The complete IET Magazine article can be read here.

There is another interesting article titled 'GPS, GLONASS, Galileo, Compass: What GNSS Race? What Competition' here. Interesting analysis.

SatNav need an integrated solution

Satellite navigation has evolved significantly in the past decade and the technology is now used in almost every walk of the life. Every body uses the satellite navigation to reach to certain destination.

But imagine that you have a navigation tool or gadget which acts as your own personal travel guide. It has satellite navigation, so when you get into your car it can direct you to where you want to go. It can choose the most carbon-efficient route and make sure you avoid crowded town centres, traffic jams and road works. It can let you know where the next petrol station is, and whether there is an Italian restaurant near your hotel. Before you arrive you will know which of the town car parks have spaces left. And when you've finally parked the car, take your guide with you and it will direct you, on foot, to your final destination.

For anyone who has found themselves stuck in a traffic jam, or has been unable to find a car park in a busy town centre, or has got lost on foot, it sounds too good to be true. Yet the technology to make it happen is already here. So why aren't we all carrying such a device in our pockets?

The question which then arises is that why the universal travel widget isn't at hand. One of the reasons for that is that several different worlds have to collide and co-operate. First of all there is a massive competition together with a huge confusion regarding the platforms in which such device can be built on. To start with we have got proprietary platforms like TomTom and Garmin, and then we've got the at least five major mobile phone operating systems.

The obvious competition between these different platforms has instigated some suspicion but apart from this the mobile companies also have yet to ¬recognize the potential of phones as navigation devices.

You can argue that many mobile phones are already GPS-enabled but in my opinion this doesn't necessary make them effective at navigation. For instance try using your blackberry as a navigation device and you’ll find that battery has quickly drained out. The mobile phone world is slowly coming to terms with the needs of navigation on mobiles, such as better ¬battery life and bigger screens. Infact GPS alone doesn't offer the precision needed to navigate pedestrians, and so to be useful needs to be combined with another positioning service such as Wi-Fi. This has been done with the iPhone, for example.

The accuracy and granularity of data used in satellite navigation systems is very critical and has to be improving all the time. The real problem lies in integration where the data needed to provide a coherent information service to a navigation device is held by different organisations in a number of different places. While there are companies that are providing some location-based information such as information about ATMs, speed cameras, train times or tourist sites but there is no company in my knowledge that offers everything.

Combining all the information and hence provided through a single device at a one point of time that information isn't going to be easy. The challenges which lies in this are not solely technical for example there's a data aggregation problem to bring it altogether, including highway changes, updates from local authorities and then there's a physical problem in gathering all that up.
Even if the above issues are solved there is still a major part of the problem which is revenue. How one would make money out of integrated Satnav device? There's a difference between what can be done technically and a viable ¬product that can be sold. How do you turn that into something that fits in a business model?"

Organisations that have valuable data rarely want to give it away for free, licences to reuse companies or government’s mapping data commercially are expensive. Similarly, there is no incentive for the Highways Agency or local authorities, for example, to share information about traffic conditions. Even the government website Transport Direct, which provides free up-to-date transport information, has restrictions on the integration of its content with other services.

So now you may realize that how trying to highlight the potential of the problem. It’s a mammoth task to bring all the above information together into one place as everyone wants their pound of flesh because everyone has developed their own data infrastructure and it's just very difficult to get them to agree.

I certainly hold the opinion that inspite of all these hiccups the demand for an all-in-one travel service almost certainly exists. People simply really want a so called integration or integrated device which can work across different ¬locations i.e. home, work, on the move etc.

It’s evident from the above facts that the emergence of a ¬genuinely integrated solution will depend on a government initiative to force public sector organisations such as Highways Agencies, Transport for London and local authorities to collaborate, or on a private sector organisation taking a ¬commanding lead in terms of developing location technologies.
Google is one such company which is creeping up with a whole series of ¬initiatives that are steadily putting the pieces in place. Best example for this is Google Maps which are now readily available on all mobile platforms and is integrated with traffic data from the Highways Agency. Not only this, the Google Maps application interface (API) allows third parties to build their own applications as well.

Google, no doubt is leading with an example in terms of it’s initiatives towards serving the customers in best possible way. Google certainly knows what the customers want which I believe a mini innovation in these current economic climate.

Location has always been such an absolutely fundamental framework for our lives, and we inevitably must embrace tools that allow us to manage that. I envisage a society in 20 years' time revolutionised by the ability to know all the location based information.

Satellite based Mobile Internet of the future

Background: The current US military satellite communications network represents decades-old technology. To meet the heightened demands of national security in the coming years, newer and more powerful systems are being developed.

Advances in information technology are fundamentally changing the way military conflicts are resolved. The ability to transmit detailed information quickly and reliably to and from all parts of the globe will help streamline military command and control and ensure information superiority, enabling faster deployment of highly mobile forces capable of adapting quickly to changing conditions in the field. Satellite communications play a pivotal role in providing the interoperable, robust, "network-centric" communications needed for future operations.

Military satellite communications (or milsatcom) systems are typically categorized as wideband, protected, or narrowband. Wideband systems emphasize high capacity. Protected systems stress antijam features, covertness, and nuclear survivability. Narrowband systems emphasize support to users who need voice or low-data-rate communications and who also may be mobile or otherwise disadvantaged (because of limited terminal capability, antenna size, environment, etc.).

For wideband communication needs, the Wideband Gapfiller Satellite program and the Advanced Wideband System will augment and eventually replace the Defense Satellite Communications System (DSCS). These satellites will transmit several gigabits of data per second—up to ten times the data flow of the satellites being replaced. Protected communications will be addressed by a global extremely high frequency (EHF) system, composed of the Advanced Extremely High Frequency System and Advanced Polar System. These systems are expected to provide about ten times the capacity of current protected satellites (the Milstar satellites). Narrowband needs are supported by the UFO (Ultrahigh-frequency Follow-On) constellation, which will be replaced by a component of the Advanced Narrowband System

Lockheed Martin Space Systems, Hughes Space and Communications and TRW have formed a National Team to build the Department of Defense's (DOD) next generation of highly secure communication satellites known as the Advanced Extremely High Frequency (AEHF) system.

The Advanced EHF programme provides the follow-on capability to the Milstar satellite programme. It provides the basis for the next generation military communications satellite system, for survivable, jam-resistant, worldwide, secure, communications for the strategic and tactical warfighter. The system replenishes the Milstar constellation in the EHF band.

Each of these Advanced EHF satellites employs more than 50 communications channels via multiple, simultaneous downlinks. Launch of the first AEHF satellite is planned for April 2008 with the second AEHF satellite scheduled for launch in April 2009.

The fully operational Advanced EHF constellation will consist of four crosslinked satellites, providing coverage of the Earth from 65° north latitude to 65° south. These satellites will provide more data throughput capability and coverage flexibility to regional and global military operations than ever before. The fifth satellite built could be used as a spare or launched to provide additional capability to the envisioned constellation.

Current Status: After being plagued with project overruns and a scaling back of the final system, the US military's next generation satellite communications network is another step closer to reality, with completion of the payload module for the third and final Advanced Extremely High Frequency (EHF) satellite.

Although the EHF band is a relatively lightly used part of the electromagnetic spectrum (30-300 GHz), it is for good reason. Atmospheric attenuation is the biggest problem faced in this band, especially around 60 GHz, however the frequencies are viable for short distance terrestrial based communication links, such as microwave Internet and telecommunication links (which already operate in this band). Millimetre wave radar, probably best known as the radar that can see through your clothes but not your skin, also operates in this band.

Designed to avoid problematic frequencies that are more susceptible to attenuation, but accepting increased overall atmospheric attenuation, are an increasing number of military and civil satellite systems that are using this band for uplink and downlink, as well as inter-satellite communication. Inter-satellite communication is really where EHF equipment shines (no atmosphere, small antennas, high data rates).

Civilian systems are currently around the Ku band (Intelsat), providing data rates of up to 2-4 Mbps (14 GHz uplink, 12 GHz downlink) however these rates have still to trickle into everyday user's hands for remote and mobile Internet access. It is more common that an aggregator will access this link/rate and use that to then portion out local Internet access. Systems such as this are in use for remote Australian territories like Cocos and Christmas Islands, and formed the backbone of Boeing's stillborn Connexion in-flight Internet access. High ongoing access costs (basically a share of the overall cost of the satellite) and limited access slots help keep the technology away from everyday use at this time. Militaries and governments around the globe also lease access on these circuits when they need the added capability, with Intelsat and Inmarsat systems being used in the first Gulf War.

Advanced EHF is designed to provide 24 hour coverage from 65 North, to 65 South across the K and Ka sub bands, and when combined with the prototyped Extended Data Rate (XDR) terminals and systems, will offer up to 8.2 Mbps data rates for around 4,000 terminals in concurrent use per satellite footprint (whether that scales to 12,000 systems in concurrent use globally isn't clear from source material).

Within the tri-satellite constellation, inter-satellite EHF links will allow terminals on opposite sides of the globe to communicate in near real-time without the use of a terrestrial link. Combined with smaller, directional antennas and the various options for anti-jamming technology, it represents a significant military capability for the US.

Already plans are being drawn up for the Transformational Satellite Communications System (T-Sat) which will replace Advanced EHF starting sometime in 2013, however it is already facing funding troubles. This could be problematic, with Advanced EHF still struggling to reach capability and the final launch not scheduled until April 2010. Dropping the fourth satellite of the Advanced EHF constellation has been planned to give the USAF time to implement T-Sat more rapidly.

If GPS and remote imaging (think Google Earth) have proven anything, it is that technology initially developed for military purposes, and extremely expensive for initial civil use, will eventually reach the point where it forms part of our daily lives without us ever being conscious of the massive investment to get to that point.

Mobile TV via Satellite

A heading of news article yesterday read: "European mobile operators are looking for economic ways of launching broadcast mobile TV services directly to handsets". This made me wonder, if there is a strong case for Mobile TV via Satellite?

Couple of days back, 3 Italia reported that it had 719,000 people using its DVB-H service by August 22, which is about 9.4 percent of its 7.68 million customer base reports Dow Jones in Italian. The figure is a good sign—at the beginning of June it was 600,000 and back in March it was 250,000, or about 3.7 percent of the subscriber base. So this proves that some people are using Mobile TV if available.

The only popular satellite Mobile TV i am aware of being used practically (please correct me if you know more) is the S-DMB being used in Korea.

According to a report in Moconews, currently some 7 million people in S. Korea are watching mobile TV--that equates to one in every seven residents of the country--but none of the operators offering DMB services has yet to make any money. Each of the six terrestrial DMB operators has piled up an accumulated loss of between $22 million and $33 million. The only mobile TV operator that charges for its service is SK Telecom-owned TU Media, which offers its DMB service over a satellite-based system (S-DMB). It has 1.2 million paid subscribers, but TU says it needs at least 2.5 million to break even in operation. That’s before it can even start to recoup its $435 million investment in satellites and networks.

The European Space Agency (ESA) has joined the DVB-H party by funding development of technologies for broadcasting TV to mobiles via satellite. ESA has called its standard DVB-SH (Digital Video Broadcast - Satellite, Handheld) and envisages using satellites to send out video at 2GHz to 4GHz (S-Band). Terrestrial repeaters would be used to give indoor coverage. Eutelsat has commissioned a new satellite to be launched in 2009, with the intention of broadcasting DVB-SHb - though it's hedging its bets by claiming it's for multimedia distribution rather than any specific technology or application. Much of the technology needed by DVB-SH doesn't yet exist, so the ESA will be issuing invitations to tender (ITT) for companies that want to have a go at developing them. First up will be a mobile chipset capable of receiving and decoding DVB-SH version b signals. The ITT is due to be published in the next few months.

Finally i found a good report on BetaNews detailing the pros and cons of Satellite Mobile TV:

It's an ambitious idea, and it's not nearly a done deal. But yesterday, a proposal was introduced before the European Parliament for a timetable by which the EU would select a few choice service providers, for the precious and narrow spectrum it will be making available for the entire continent. It will require the consent and cooperation of all 27 member states - something the EU rarely gets even with less ambitious proposals.

Here's what it means: Last February, the EU established two small chunks of radio spectrum - 1980-2010 MHz and 2170-2200 MHz - as reserve space for future MSS broadcasting. Under normal EU law, member states would each have the right to select their own service providers for satellite TV and radio service for their respective countries. In fact, if the EU were to change its mind now and do nothing, that's what EU states would do next.

But there's two big problems: First of all, no single EU country is very big, geographically speaking, compared to the whole of Europe. A satellite signal covers a very broad portion of the Earth, so any service provider licensed for, say, France could probably have its signal picked up in southern Finland. Simply put, the laws of physics dictate a wide coverage area that technology cannot circumvent...unless every mobile TV receiver in Europe were custom-built for each member country. (If you're thinking like a manufacturer of DVD consoles, you might not be too opposed to trying that.)

Even if France's signal and England's and Bulgaria's and all the others could be picked up everywhere else - which, if you think about it, will be the case anyway - Bulgaria's service provider wouldn't want its signal overlapping England's. And that leads us to the second big problem: There's not enough MSS spectrum available in the 2 GHz band to go around.

So the European Union is stepping in, or at least attempting to. But in order for member states to allow it to do so, it has to formally present its case to those states for why it has the authority to do so. Imagine if, under a different style of US constitution, in order for the federal government to make its case for regulating the public airwaves, it had to get all 50 states' consent to giving up their own rights to do so individually.
Thus a large part of the EU proposal yesterday explains - as it must do under European law - why it's claiming the authority to propose a national selection process for MSS providers.

For its claim to qualify as valid, it has to meet two tests under the EU constitution. First, the claim must meet the Subsidiarity Principle: essentially, that the nature of the job at hand means it can be performed better by the EU than by all the 27 states acting independently. In other words, the EU has to prove it can do the job not because it's better at these sorts of things, but because the problem at hand makes a single body better suited to the task.

Here is where the EU has physics on its side: Satellite signals cover broad territory, and states' boundaries do not. "Selection and issuance of rights over the same spectrum to different satellite operators in different Member States would prevent satellites from covering their natural footprint," the EU proposal reads, "which by nature covers a large number of countries; it would risk fragmenting the satellite communications market and eliminate the natural advantage of satellites compared to other modes of communication. The mobile character of the services involved also means that citizens travelling in the EU should benefit from the availability of such services throughout the EU."

Second, the EU's case must meet the Proportionality Principle. This means it can't claim more authority than it needs to do the job...and once the job is done, it steps out of the way. In other words, it can't appoint a permanent commission like the FCC.

In making that part of the case, the EU goes on, "The proposal will create a mechanism for coordinating the selection and definition of certain conditions to be attached to rights of use of spectrum. It will not touch upon the right of Member States to grant the authorizations to use the spectrum or to attach specific conditions applying to the provision of services in areas which are not harmonized. Member States will be closely involved in elaborating the details of the selection procedure."

Here is where critics say the EU's case may fall apart. In order to win the authority to drive the MSS adoption process, the EU is limiting itself to driving the selection process for prospective service providers. Once that job is done, it's leaving it up to member states to apportion per-country licenses to those companies, for channels which the EU would already have selected as well.

On the one hand, it doesn't make sense. In order to sell its plan, the EU is leaving open the option for member states to deny licenses. But assuming a state does so, how could it block the reception of a signal from a service provider whose license was denied? That might take a technological solution...which brings up the whole "per-country" manufacturing option for MSS receivers again.

On the other hand, only such a hare-brained scheme might just work, because member states don't want to be perceived by their citizens as ceding any part of their authority to a federal institution. Giving them the right to say "no" could be a kind of ceremonial concession, not unlike the establishment of a constitutional monarchy where the monarch is essentially a face on a coin - which is a state of affairs not unfamiliar to member states.

"Since industry so far could not agree on a single standard for mobile TV, commercial launches of mobile TV are delayed," reads a statement from the EU's central authority in Brussels last month. "Europe's competitors, most notably from Asia, have made significant progress - partly due to state intervention - and Europe risks losing its competitive edge unless sufficient momentum is achieved. This is why there is a need to develop a 'blueprint' for mobile TV in Europe."