The Bluetooth standards maze

October 2, 2007

This posting focuses on low-power wireless technologies that enable communication between devices that are located within a few feet of each other. This can apply to both voice communications as well as data communication.

This whole area is becoming quite complex with a whole raft of standards being worked on – ULB, UWB, Wibree, Zigbee etc. This may seem rather strange bearing in mind the wide-scale use of the key wireless technology in this space – Bluetooth.

We are all familiar with Bluetooth as it is now as ubiquitous in use as Wi-Fi but it has had a chequered history by any standard and this has negatively affected its take-up across many market sectors.

Bluetooth first saw the light of day as an ‘invention’ by Ericsson in Sweden back in 1994 and was intended as a wireless standard for use as a low-power inter-’gadget’ communication mechanism (Ericsson actually closed the Bluetooth division in 2004). This initially meant hands-free ear pieces for use with mobile phones. This is actually quite a demanding application as there is no room for drop outs as in an IP network as this would be a cause for severe dissatisfaction from users.

Incidentally, I always remember buying my first Sony Ericsson hands-free earpiece that I bought in 2000 as everyone kept giving me weird looks when I wore it in the street – nothing much has changed I think!

Standardisation of Bluetooth was taken over by the Bluetooth Special Interest Group (SIG) following its formation in 1998 by Sony Ericsson, IBM, Intel, Toshiba, and Nokia. Like many new technologies, it was launched with great industry fanfare as the up-and-coming new thing. This was pretty much at the same time as WAP (Covered in a previous post: WAP, GPRS, HSDPA on the move!) was being evangelised. Both of these initiatives initially failed to live up to consumer expectations following the extensive press and vendor coverage.

Bluetooth’s strength lies in its core feature set:

  • It operates in the ‘no licence’ industrial, scientific and medical (ISM) spectrum of 2.4 to 2.485 GHz (as does Wi-Fi of course)
  • It uses a spread spectrum, frequency hopping, full-duplex signal at a nominal rate of 1600 hops/sec
  • Power can be altered from 100mW (Class 1) down to 1mW (Class 3), thus effectively reducing the distance of transmission from 10 metres to 1 metre
  • It uses adaptive frequency hopping (AFH) capability with the transmission hopping between 79 frequencies at 1 MHz intervals to help reduce co-cannel interference from other users of the ISM band. This is key to giving Bluetooth a high degree of interference immunity
  • Bluetooth pairing occurs when two Bluetooth devices agree to communicate with each other and establish a connection. This works because each Bluetooth device has a unique name given it by the user or as set as the default

Several issues beset early Bluetooth deployments:

  • A large lack of compatibility between devices meant that Bluetooth devices from different vendors failed to work with each other. This caused quite a few problems both in the hands-free mobile world and the personal computer peripheral world and led to several quick updates.
  • In the PC world, user interfaces were poor forcing ordinary users to become experts in finding their way around arcane set-up menus.
  • There were also a considerable number of issues arising in the area of security. There was much discussion about Bluejacking where an individual could send unsolicited messages to nearby phones that were ‘discoverable’. However, people that turned off discoverability needed an extra step to receive legitimate data transfers thus complicated ‘legitimate’ use.

Early versions of the standard were fraught with problems and the 1Mbit/s v1.0 release was rapidly updated to v1.1 which overcame many of the early problems. This was followed up by v1.2 in 2003 which helped reduce co-channel interference from non-Bluetooth wireless technologies such as Wi-Fi.

In 2004, V2.0 + Enhanced Data Rate (EDR) was announced that offered higher data rates – up to 3Mbit/s – and reduced power consumption.

To bring us up to date, V2.1 + Enhanced Data Rate (EDR) was released in August 2007 which offered a number of enhancements the major of which seems to be an improved and easier-to-use mechanism for pairing devices.

The next version of Bluetooth is v3.0 which will be based on ultra-wideband (UWB) wireless technology. This is called high speed Bluetooth while there is another proposed variant, announced in June 2007, called Ultra Low Power Bluetooth (ULB).

During this spread of updates, most of the early days problems that plagued Bluetooth have been addressed but it cannot be assumed that Bluetooth’s market share is unassailable as there are a number of alternatives on the table as it is viewed that Bluetooth does not meet all the market’s needs – especially the automotive market.

Low-power wireless

Ultra Low-power Bluetooth (ULB)

Before talking about ULB, we need to look at one of its antecedents, Wibree.

This must be one of the shortest lived ‘standards’ of all time! Wibree was announced in October 2006 by Nokia though they did indicate that they would be willing to merge its activities with other standards activities if that made sense.

“Nokia today introduced Wibree technology as an open industry initiative extending local connectivity to small devices… consuming only a fraction of the power compared to other such radio technologies, enabling smaller and less costly implementations and being easy to integrate with Bluetooth solutions.”

Nokia felt that there was no agreed open standard for ultra-low power communications so it decided that it was going to develop one. One of the features that consumes power in Bluetooth is its frequency hopping capability so Wibree would not use it. Wibree is also more tuned to data applications as it used variable packet lengths unlike the fixed packet length of Bluetooth. This looks similar to the major argument that took place when ATM (The demise of ATM) was first mooted. The voice community wanted short packets while the data community wanted long or variable packets – the industry ended up with a compromise that suited neither application.

More on Wibree can be found at wibree.com . According to this site:

“Wibree and Bluetooth technology are complementary technologies. Bluetooth technology is well-suited for streaming and data-intensive applications such as file transfer and Wibree is designed for applications where ultra low power consumption, small size and low cost are the critical requirements … such as watches and sports sensors”.

On June 12th 2007 Wibree merged with the Bluetooth SIG and the webcast of the event can be seen here. This will result in Wibree becoming part of the Bluetooth specification as an ultra low-power extension of Bluetooth known as ULB.

ULB is intended to complement the existing Bluetooth standard by incorporating Wibree’s original target of reducing the power consumption of devices using it – it aims to consume only a fraction of the power current Bluetooth devices consume. ULB will be designed to operate in a standalone mode or in a dual-mode as a bolt-on to Bluetooth. ULB will reuse existing Bluetooth antennas and needs just a small bit of addition logic when operating in dual-mode with standard Bluetooth so it should not add too much to costs.

When announced, the Bluetooth SIG said that NLB was aimed at wireless enabling small personal devices such as sports sensors (heart rate monitors), healthcare monitors (blood pressure monitors), watches (remote control of phones or MP3 players) and automotive devices (tyre pressure monitors).

Zigbee

The Zigbee standard is managed by the Zigbee Alliance and was developed by the IEEE as standard 802.15.4 It was ratified in 2004.

According to the Alliance site:

“ZigBee was created to address the market need for a cost-effective, standards-based wireless networking solution that supports low data-rates, low-power consumption, security, and reliability.

ZigBee is the only standards-based technology that addresses the unique needs of most remote monitoring and control and sensory network applications.”

This puts the Bluetooth ULB standard in competition with Zigbee as it aims to be cheaper and simpler to implement than Bluetooth itself. In a similar way to the ULB team announcements, Zigbee uses about 10% of the software and power required to run a Bluetooth node..

A good overview can be found here – ZigBee Alliance Tutorial – which talks about all the same applications as outlined in the joint Wibree / Bluetooth NLB announcement above. Zigbee’s characteristics are:

  • Low power compared to Bluetooth
  • High resilience as iill operate in a much noisier environment that Bluetooth or Wi-Fi
  • Full mesh working between nodes
  • 250kbit/s data rate
  • Up to 65,536 nodes.

The alliance says this makes Zigbee ideal for both home automation and industrial applications.

It’s interesting to see that one of Zigbee’s standard competitors has posted an article entitled New Tests Cast Doubts on ZigBee . All’s fair in love and war I guess!

So there we have it. It looks like Bluetooth ULB is being defined to compete with Zigbee.


High-speed wireless

High Speed Bluetooth 3.0

There doesn’t seem to be too much information to be found on the proposed Bluetooth version 3.0. However on the WiMedia Alliance site I found the statement by Michael Foley, Executive Director, Bluetooth SIG. WiMedia is the organisation that lies behind Ultra Wide-band (UWB) wireless standards.

“Having considered the UWB technology options, the decision ultimately came down to what our members want, which is to leverage their current investments in both UWB and Bluetooth technologies and meet the high-speed demands of their customers. By working closely with the WiMedia Alliance to create the next version of Bluetooth technology, we will enable our members to do just that.”

According to a May 2007 presentation entitled High-Speed Bluetooth on the Wimedia site, the Bluetooth SIG will reference the WiMedia Alliance [UWB] specification and the solution will be branded with Bluetooth trademarks. The solution will be backwards compatible with the current 2.0 Bluetooth standard.

It also talks about a combined Bluetooth/UWB stack:

  • With high data rate mode devices containing two radios initially
  • Over time, the radios will become more tightly integrated sharing components

The specification will be completed in Q4 2007 and first silicon prototyping complete in Q3 2008. I have to say that this approach does not look to be either elegant or low cost to me. However, time will tell.

That completes the Bluetooth camp of wireless technologies. Let’s look at some others.


Ultra-wide Bandwidth (UWB)

As the Bluetooth SIG has adopted UWB as the base of Bluetooth 3.0 what actually is UWB. A good UWB overview presentation can be found here. Essentially, UWB is a wireless protocol that can deliver a high bandwidth over short distances.

It’s characteristics are:

  • UWB uses spread spectrum techniques over a very wide bandwidth in the 3.1 to 10GHz spectrum in the US and 6.0 to 8.5GHz in Europe
  • It uses very low power so that it ‘co-exist’ with other services that use the same spectrum
  • It aims to deliver 480Mbit/s at distances of several metres

The following diagram from the presentation describes it well:

In theory, there should never be an instance where UWB interferes with an existing licensed service. In some ways, this has similarities to BPL (The curse of BPL), though it should not be so profound in its effects. To avoid interference it uses Detect and Avoid (DAA) technology which I guess is self defining in its description without going into too much detail here.

One company that is making UWB chips is Artimi based in Cambridge, UK.
Wireless USB (WUSB)

In the same way that the Bluetooth SIG has adopted UWB, the USB Implementers Forum has adopted WiMedia’s UWB specification as the basis of Wireless USB. According to Jeff Ravencraft, President and Chairman, USB-IF and Technology Strategist, Intel:

“Certified Wireless USB from the USB-IF, built on WiMedia’s UWB platform, is designed to usher in today’s more than 2 billion wired USB devices into the area of wireless connectivity while providing a robust wireless solution for future implementations. The WiMedia Radio Platform meets our objective of using industry standards to ensure coexistence with other WiMedia UWB connectivity protocols.”

A presentation on Wireless USB can be downloaded here

Wireless USB will deliver around the same bandwidth as Bluetooth 3.0 – 480Mbit/s at 3 metres because it is based on the same technology and will be built into Microsoft Vista.™.

One is bound to ask, what the difference is between Wireless USB and Bluetooth as they are going to be based on the same standard. Well one answer is that Wireless USB products are being shipped today as seen in the Belkin Wireless USB Adapter as shown on the right.

A real benefit of both standards adopting UWB will be that both standards will use the same underlying radio. Manufacturers can choose whatever which ever standard they want and there is no need to change hardware designs. This can only help both standard’s adoption.

However, because of the wide spectrum required to run UWB – multiple GHz – different spectrum ranges in each region are being allocated. This is a very big problem as it means that radios in each country or region will need to be different to accommodate the disparate regulatory requirements.

In the same way that Bluetooth ULB will compete with Zigbee (an available technology), Bluetooth 3.0 will compete with Wireless USB (also an available technology).

Round up

So there you have it – the relationships between Bluetooth 2.0, Bluetooth 3.0, Wibree, Bluetooth ULB, Zigbee, High speed Bluetooth, UWB and Wireless USB. So things are clear now right?

So what about Wi-Fi’s big brother WIMAX? And don’t let us forget about HSPDA (WAP, GPRS, HSDPA on the move!), the 3G answer to broadband services? At least these can be put in a category of wide area wireless services to separate them from near distance wireless technologies. I have to say I find all these standards very confusing and makes any decision that relies on a bet about which technology will win out in the long run exceedingly risky. At least Bluetooth 3.0 and Wireless USB use the same radio!

At an industry conference I attended this morning, a speaker talked about an “arms war” between telcos and technology vendors. If you add standards bodies to this mix, I really do wonder where we consumers are placed in their priorities. Can you see PC manufacturers building all these standards onto their machines?

I could also write about WIMAX, Near Field Communications, Z-wave and RF-ID but I think that is better left for another day!

6 Comments | All, Internet, Mobile, Networks, Wireless | Permalink
Posted by Chris Gare

EBay paid too much for Skype

October 2, 2007

I don’t normally post news, but I couldn’t resist posting this as it so close to my heart. Ever since the deal was done everyone has been asking whether it was worth what they paid.

The  article was in the London Evening Standard today.

ONLINE auctioneer eBay today admitted it had paid too much for internet telephone service Skype in 2005.

EBay, which forked out $2.6 billion (fl.3 billion), will now take a $1.4 billion charge on the company as it fails to convert users into revenue.

Skype’s chief executive Nikias Zennström, one of eBay’s founders, will step down, but the company denies he is walking the plank.

EBay will pay some investors $530 million to settle future obligations under the disastrous Skype deal.

In a desperate bid to get the deal over the line in 2005, eBay promised an extra $L7 billion to Skype investors if the unit met certain targets including number of users.

Now it is offering those shareholders $530 million as “an early, one-time payout”. The parent company will write down $900 million in the value of Skype.

Since eBay took over, Skype’s membership accounts have risen past 220 million, but it earned just $90 million during the second quarter of 2007, far below projections.

I wonder if this will cool some of the outrageous values being put on some of the social network services?

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Posted by Chris Gare

Do you know your ENUM?

September 24, 2007

Isn’t it funny how a new concept is often universally derided as nonsensical? There are many examples of this but none more so than Voice over IP (VoIP) (I mean Internet Protocol not Intellectual Property).

But just look at how universal VoIP has become over the last fifteen years despite all the early knocking and mumblings that it would, could, not ever work. When I first started talking about VoIP in the mid 1990s, after a visit to Vocaltec in Israel, I was even banned from a particular country as my views were considered seditious. Looking at the markets of 2007, I guess they may have been right! However, trying to hold back the inevitable is never a good reaction to a possibly disruptive technology though this is still occurring on a wide scale in today’s telecommunications world. [Picture credit: Enum.at]

Earlier this year I wrote about the challenges of what I called islands of isolation in a posting entitled Islands of communication or isolation?. I consider this to be one of the main challenges any new communications technology or service needs to face up to if it is going to achieve world-wide penetration. Sometimes just an accepted standard can tip a new technology into global acclaim. A good example of this is Wi-Fi or ADSL. Because of the nature of these technologies, equipment based on these standards can be used even by a single individual so a market can be grown from even a small installed base when it is reinforced by a multiplicity of vendors jumping on the bandwagon when they think the market is big enough.

However, many communication technologies or services require something more before they can become truly ubiquitous and VoIP is just one of those services. Of course many of these additional needs can be successfully bypassed by ‘putting up the proverbial finger’ to the existing approach by developing completely stand-alone services based on proprietary technologies as so successfully demonstrated by Skype in the VoIP world. The reason Skype become so successful at such an early stage was that the service was run independently of the existing circuit-switched Public Switched Telephone Network (PSTN). This was quite a deliberate and wholly successful strategy. What was the issue that Skype was trying to circumvent (putting their views of their perceived monopolistic characteristics of the telco industry to one side)? Telephone numbers.

Numbering was the one important feature that made the traditional telephone industry so successful. Unfortunately, it is also the lack of this one feature that has held back the rollout of VoIP services more than any other. The issue is that every user of a traditional telephone had their own unique telephone number (backed up by agreed standards drafted by the ITU). As long as you knew an individual’s number you could call them where ever they were located. In the case of VoIP, you may not be able to find out their address if they use a different VoIP operator to yourself leading to multiple islands of VoIP users who are unable to directly communicate with each other.

If the user chooses to use a VoIP-based telephone service they still expect to be able talk to anyone no matter what service provider they have chosen to use, whether that be another user of the VoIP service or a colleague not using VoIP but an ordinary telephone.

One of the key issues cluttering the path to achieving this is that VoIP runs on an IP network that uses a completely different way of identifying users than traditional PSTN or mobile networks. IP networks use an IP addresses as dictated by the IPv4 standard ( IPv6 to the rescue – eh? ) while public telephone networks use the E.164 standard as maintained by the ITU in Geneva. So if a VoIP user wants to make a call to an individual’s desk or mobile phone or vice versa a cross-network directory look up is needed before a physical connection can be made.

This is where the concept of Telephone Number Mapping (ENUM) comes into its own as one of the key elements required to achieve the vision of converged VoIP and PSTN services. The key goal of ENUM is to enable calls to be made between the two worlds of VoIP and PSTN as easy as between PSTN users. This must be achieved if VoIP services are are to become truly ubiquitous.

In reality no individual really cares whether a call is being completed on a VoIP network or not as long as the quality is adequate. They certainly do care about cost of a call and this turned out to be one of the main drivers causing the rise of VoIP services as they are used to bypass the tradition financial settlement regimes that exist in the PSTN world (Revector, detecting the dark side of VoIP).

How does ENUM work?

There are three aspects that need to be considered:

  1. How is an individual is identified on the IP network or Internet (an IP network can be a closed IP network used by a carrier where a guaranteed quality of service is implemented unlike the Internet).
  2. How the individual is identified on the PSTN network segment from an addressing or telephone number basis.
  3. How these two segments inter-work.

The IP network segment: We are all familiar with the concept of a URL or Uniform Resource Locator that is used to identify a web site. For example, the URL of this blog is http://technologyinside.com . In fact a URL is a subset of a Uniform Resource Identifier (URI) along with a Uniform Resource Name (URN). A URL refers to the domain e.g. a company name, while the URI operates at a finer granularity and can identify an individual within that company such as with an email address. For VoIP calls, as an individual is the recipient of a call rather than the company, URIs are used as the address. The same concept is used with SIP services as explained in sip, Sip, SIP – Gulp! The IETF standard that talks about E.164 and DNS mapping is RFC 2916.

URIs can be used to specify the destination device of a real-time session e.g.

  1. IM: sip: xxx@yyy.com (Windows Messenger uses SIP)
  2. Phone: sip: 1234 1234 1234@yyy.com; user=phone
  3. FAX: sip: 1234 1234 1235@yyy.com; user=fax

On the PSTN segment: A user is identified by their E.164 telephone number used by both fixed and mobile / cell phones. I guess there is no need to explain the format of these as they are an example of an ITU standard that is truly global!

Mapping of the IP and PSTN worlds:

There are two types of VoIP call. Those that are carried end-to-end on an IP network or other calls that start on a VoIP network but end on a PSTN network or vice versa. For the second type, call. mapping is required.

Mapping between the two worlds is in essence managed by an on-line directory that can be accessed by either party – the VoIP operator wishing to complete a call on a traditional telephone or a PSTN operator wishing complete a call on a VoIP network. These directories are maintained ENUM registrars. Individual user records therefore contain both the E.164 number AND the VoIP identifier for an individual.

The Registrar’s function to manage both the database and the security issues surrounding the maintenance of a public database i.e. only the individual or company (in the case of private dial plans) that are concerned with the record are able to change its contents.

The translation procedure: When a call between a VoIP user and a PSTN user is initiated, four steps are involved. Of course, the user must be ENUM-enabled by having an ENUM record with an ENUM registrar.

  1. The VoIP user’s software, or their company’s PBX i.e. their User Agent translates the E.164 number into ENUM format as described in RFC 3761.To convert an E.164 number to an ENUM the follows steps are required:
    1. +44 1050 6416 (The E.164 telephone number)
    2. 44105056416 (Removal of all characters except numbers)
    3. 61465050144 (Reversal of the number order)
    4. 6.1.4.6.5.0.5.1.3.4 (Insertion of dots between the numbers)
    5. 6.1.4.6.5.0.5.1.3.4.e164.arpa (Adding the global ENUM domain)
  2. A request is sent to the Domain Number Service (DNS) to look up the ENUM domain requested.
  3. A query in a format specified by RFC 3403 is sent to the ENUM registrar’s domain which either returns the PSTN number or the URI number of the caller – whichever is requested.
  4. The call is now initiated and completed.

For this process to work universally then every user that uses both VoIP and PSTN services need to have an ENUM record. That is a problem today as it is just not the case.

ENUM Registrars

In a number of countries top-level public ENUM registrars have been set up driven by the ITU. For example this is the ENUM registrar in Austria – http://www.enum.at They then hold the DNS pointers to other ENUM registrars in Austria. Another example is Ireland’s ENUM registry.

However, in the USA, ENUM services are in the hands of private registrars.

If you sign up for a VoIP service that provides you with an E.164 telephone number, your VoIP provider will act as a registrar and hence your details will be automatically registered for look-up through a DNS call. If you do not use one of these services, it is possible to register yourself with an independent registrar.

Local Number Portability (LNP)

During the early days of VoIP services, many ENUM registrars were operated by 3rd party clearing houses acting on a federated basis who were quick to jump on an unaddressed need. Of course, these registrars charge for look-up services. Other third party companies offer provide “trusted and neutral” number database services such as Neustar, e164 and Nominum in the USA who not only offer ENUM services but also Local Number Portability services. To quote Neustar:

“LNP is the ability of a phone service customer in North America to retain their local phone number and access to advanced calling features when they switch their local phone service to another local service provider. LNP helps ensure successful local telephone competition, since without LNP, subscribers might be unwilling to switch service providers.”

However, as we start to see more and more VoIP service providers and more and more traditional voice carriers offering VoIP service to their customers we will see more carriers offering ENUM numbering capabilities. Moreover, They could also use ENUM technology to help reduce costs of the need to support Local Number Portability by managing translation / mapping databases themselves rather than paying a 3rd party for the capability. To quote an article in Telephony Online:

“Not all service providers are rushing to do their own ENUM implementations, said Lynda Starr, a senior analyst with Frost & Sullivan who specializes in IP communications. “Some say it’s not worth doing yet because VoIP traffic is still small.” Eventually, however, Starr estimates that service providers could save about 20% of the cost of a call by implementing ENUM – even more if they exchange traffic with one another as peers.“

An ITU committee is being planned by the ITU to look at service-provider hosted ENUM databases but the view is that it will be slow to be implemented as is usually the case with ITU standards.

Round up

If every PSTN network had an ENUM-compliant gateway and database, then truly converged voice services could be created and user’s preferences concerning on which device they would like to take calls could be accommodated. Today, as far as I am aware, even the neutral 3rd party ENUM registrars do not currently share their records with other parties, further exacerbating the numbering islands issue. This means you need to know which Registrar to go to before a call can be set up.

It is early days yet but we will undoubtedly start to see more and more carriers implementing ENUM capabilities rather than some of the proprietary number translation solutions that started with the concept of Intelligent Networks in the 1980s. In the mean time the industry will carry on in a sub-optimal way hoping beyond hope that something will happen to sort it all out soon. The real issue is that ENUM registries are the keystone capability needed to make VoIP services globally ubiquitous but they can hardly be considered a major opportunity to make money on a standalone basis. Rather they are an embedded capability in VoIP or PSTN service providers or neutral Internet exchanges so there is little incentive to pour vast amounts of money into the capability which will lead to continuing snail-like growth.

As is the case with standards, even though most would agree that using E.164 numbering is the way forward, there is another proposal called SRV or service record that proposes to use email addresses as the denomination rather than telephone numbers. The logic of this is that it would be driven by by IT directors riding on the back of disappearing PBXs and who are swapping over to Asterisk open-software systems. That is a story for another time however.

Addendum #1: sip, Sip, SIP – Gulp!

3 Comments | All, Internet, Networks, Software | Permalink
Posted by Chris Gare

How to Be a Disruptor

September 11, 2007

An excellent article from Sandhill.com on running a software business along disruptive lines. Written by the CEO of MySQL, it looks like it needs a lot of traditional common sense!

These are the key issues  he talks about:

Follow No Model
Get Rich Slow
Make Adoption Easy
Run a Distributed Workforce
Foster a Culture of Experimentation
Develop Openly
Leverage the Ecosystem
Make Everyone Listen to Customers
Run Sales as a Science
Fraternize with the Enemy

Take a read: How to Be a Disruptor

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Posted by Chris Gare

WAP, GPRS, HSDPA on the move!

September 4, 2007

Over the last few months I have written many posts about Internet technologies but they have been pretty much focussed on terrestrial rather than wireless networks (other than dabbling in Wi-Fi with my overview of The Cloud. – The Cloud hotspotting the planet). This exercise was rather interesting as I needed to go back to the beginning and look at how the technologies evolved starting with The demise of ATM.

Back in 1994 a colleague of mine, Gavin Thomas, wrote about Mobile Data protocols and it’s interesting to glance back to see how ‘crude’ mobile data services were at the time. Of course, you would expect that to be the case as GSM Digital Cellular Radio was a pretty new concept at the time as well. In that 1993 post I ended with the statement that “GSM has a bright future”. Maybe it should have read ” the future is Orange”! No one foresaw in those days the up and coming explosive growth of GSM and mobile phone usage. Certainly n one predicted the surge in use of SMS.

Acronym hell has extended itself to mobile services over the last few years and the market has become littered with three, four and even five letter acronyms. In particular, wireless Internet started with a three letter acronym back in the late 1990s – WAP (Wireless Access Protocol), progressing through a four letter acronym, GPRS (General Packet Radio Service) and Enhanced Data GSM Environment (EDGE) and is now moving to a five letter broadband 3G acronym – HSDPA (High-Speed Downlink Packet Access). Phew!

The history of mobile data services has been littered with undelivered hype over the years that still lives on today. However, that hype led to the development of services that really do work unlike some of the early initiatives like WAP.

Ah, WAP, now that was interesting. I would probably put this at the top of my list of over-hyped protocols of all time. At least when ATM was hyped this only took place within the telecommunications community whereas WAP was hyped to the world’s consumers which created much more visibility of ‘egg on the face’ for mobile operators and manufacturers.

So what was WAP?

In the late 1990s the world was agog with the Internet which was accessed using personal computers via LANs or dial-up modems. There was clearly an opportunity (whether it was right or wrong) to bring the ‘Internet’ to the mobile or cell phone. I have put quotation marks around the Internet as the mobile industry has never seen the Internet in the same light as PC users – more on this later.

The WAP initiative was aimed at achieving this goal and at least it can be credited with a concept that lives on to this day - Mobile Internet. Data facilities on mobile phones were really quite crude at the time. Displays were monochrome with a very limited resolution. Moreover, the data rates that were achievable at the time over the air were really very low so this necessitated WAP content standards to take this into account.

There were several aspects that needed standardising under the WAP banner:

  • Transmission protocols. WAP defined how packets were handled on a 2G wireless network and consisted of wireless versions TCP and UDP as seen on the Internet and also used WTP (Wireless transaction protocol) to control communications between the mobile phone and the base station. WTP itself contained an error correction capability to better help cope with unreliable wire bearer.
  • Mobile HTML: It was immediately recognised that due to the limited screen size and the low data rates achievable on a mobile phone a very simplified version of HTML was required for use with mobile web sites. This led to the development of WML (Wireless Markup Language). This was a a VERY cut down version of HTML with very little capability and any graphic used being tiny as well. Towards the end of the 90s WAP 2.0 was defined which improved things somewhat and was based on a cut down of XHTML.

WAP clearly did not live up to its promise of a mobile version of the Internet with it’s crude and constrained user interface, high latency, the need to struggle with arcane menu structures (has anything changed here in ten years?) and to access services using exceedingly slow data rates experienced on the mobile networks of the day.

However, this did not stop mobile service operators from over hyping WAP services with endless hoarding and TV adverts extolling Internet access from mobiles. At one time it looked as if mobile operator advertising departments never talked to their engineering departments and were living in a world of their own that bore little relation to reality.

It all had to crash and it did along with the ‘Internet bubble’ in 2001. Many mobile operators sold their WAP service as an ‘open’ service similar to the Internet. In reality, they were closed garden services that forced users to visit their company portal as their first port of call making it well nigh impossible for small application developers to get their services in front of users. One could ask how much this has changed by 2007?

I should not forget to also mention that the cost of using WAP services was very high based as it was on bits transmitted. This led to shockingly high bills and low usage and provided one of the great motivators behind the ‘unforeseen’ growth of SMS services.

I believe that much of this still lives on in the conscious and unconscious memory of consumers and held back major usage of mobile data services for many years.

Along comes the ‘always-on’ GPRS service

After licking the WAP wounds for several years, it was clearly recognised that something better was required if data services were take off for mobile operators. One of the big issues for WAP were the poor data transmission speeds achieved so GPRS (General Packet Radio Service) was born.

GPRS is an IPv4-based packet switched based protocol where data users share the same data channel in a cell. Increased data rates in GPRS derives from the knitting together of multiple TDMA time slots where each individual GSM time slot can manage between 9.6 to 21.4 Kbps. Linking together slots can deliver greater than 40kbit/s ( up to 80kbit/s) depending on the configuration implemented.

GPRS users are connected all the time and have access to the maximum upstream bandwidth available if no other users in their cell are recieving data at the same time.

The improved data rate (that is in the range of an old dial-up modem) and improved reliability experienced when using GPRS has definitely led to a wider use of data services on the internet. Incidentally, a shared packet service should mean lowered cost but as users are still billed on a kilobits transmitted basis, GPRS bills are still shockingly high if the service is used a lot.

GPRS services are so reliable that there is wide spread availability of GPRS routers as shown in the picture above (Linksys) which are often used for LAN back up capabilities.

GPRS was definitely a step in the right direction.

Gaining an EDGE

EDGE (Enhanced Data rates for GSM Evolution) is an upgrade to GPRS that has gained some popularity in the USA and Europe and is known as a 2.5G service (although it is derives from 3G standards).

EDGE can be deployed by any carrier who offers GPRS services and represents an upgrade to GPRS by requiring a swap-out to an EDGE compatible transceiver and base station subsystem.

By using an 8PSK (8 phase shift keying) modulation scheme on each time slot it’s possible to increase data rates within a single time slot to 48kbit/s. Thus, in theory, it would be be possible, by combining all 8 times slots, to deliver an aggregate 384kbit/s data service. In practice this would not be possible as there would be no spare bandwidth available for voice services!

All in all EDGE achieves what it set out to achieve – higher data rates without an upgrade to full 3G capability and has been widely deployed.

The promise of the HSDA family

Following on from WAP, GPRS and EDGE have been the dominant protocols used for mobile data access for a number of years now. Achieved data rates are still slow by ADSL standards and this has put off many users after they have played with them for a bit.

With the tens of billions of $ spent on 3G licences at the end of the last century one would have imagined that we all would have access to megabit data rates on our mobile or cell phones by now, but that has just not been the case. 3G has been slow to be deployed and presented many operational issues that needed be resolved.

The Universal Mobile Telecommunications System (UMTS) known as 3GSM uses W-CDMA spread spectrum technology as its air interface and delivers its data services under the standards known as HSDPA (High-Speed Downlink Packet Access) and HSUPA (High-Speed Uplink Packet Access) known collectively as HSDA (High-Speed Data Access).

Unlike the TDMA technology used in GSM, W-CDMA is a spread spectrum technology where all users transmit ‘on the top’ of each other over a wide spectrum, in this case 5MHz radio channels. The equipment identifies individual users in the aggregate stream of data through the use of unique user codes] that can be detected. (I explained how spread spectrum radio works in 1992 in Spread Spectrum Radio). The use of this air interface adopted makes a 3G service incompatible with GSM.

In theory, W-CDMA is able to support data rates up to 14mbit/s but in reality offered rates are in the 384Kbit/s to 3.6Mbit/s and is delivered using a dedicated down link channel called the HS-DSCH, (High-Speed Downlink Shared Channel) which allows higher bit rate transmission than ordinary channels. Control functions are carried on sister channels. The HS-DSCH channel is shared between all users in a cell so in practice it would not be possible to deliver the ceiling data rate to any more than a single subscriber which makes me wonder how the industry is going to support lots of mobile TV users on a single cell? More on this issue in a future post.

Standardisation of HSDPA is carried out by the 3rd Generation Partnership Project (3GPP).

Inevitably, because of the ultra slow roll out of UMTS 3G networks, HSDPA will take a long time to get to your front door although this is happening is quite a few countries. Here in the UK, the 3 network is currently launching (August 2007) its HSDPA data service which will be followed by a HSUPA capability at a later date. Initially it will only offer HSDPA data cards for PCs.

Interestingly, The Register reports that 3 will offer 2.8Mbit/s and the the tariff will start at £10 Sterling a month for the Broadband Lite service providing 1Gbytes of data rising to £25 for 7Gbytes with the Broadband Max service.

You can pre-order a broadband modem now as shown on the right.

Incidentally, Vodafone’s UK HSDPA service can be found here and their 7.2Mbit/s service here.

The future is LTE

Another project within 3GPP is the Long Term Evolution (LTE) activity as a part of Release 8. The core focus of the LTE team is, as you would expect, on increasing available bandwidths but there are a number of other concerns they are working on.

  • Reduction of latency: Latency is not an issue for streamed services but is a prime concern for interactive services. There is no point post-WAP launching advanced interactive services if users have to wait around like in the early days of the Internet. Users have been there before.
  • Cost reduction: This is pretty self evident but the activity is focussed on reducing operator’s deployment costs not reducing consumer charge rates!
  • QoS capability: The ubiquitous need for policy and QoS capability and I’ve explored in depth on fixed networks.

The System Architecture Evolution (SAE) is another project that is running in parallel with but behind the LTE. It comes as little surprise that the SAE is looking at creating a flat all-IP network core which will (supposedly) be the key mechanism by which operators will reduce their operating costs. This still debatable to my mind.

Details of this new architecture can be found under the auspices of the Telecoms & Internet Services & Protocols for Advanced Neworks or TISPAN (a six letter acronym!) which is a joint activity between ETSI and 3GPP. To quote from the web site:

“Building upon the work already done by 3GPP in creating the SIP-based IMS (IP Multimedia Subsystem), TISPAN and 3GPP are now working together to define a harmonized IMS-centric core for both wireless and wireline networks.

This harmonized ALL IP network has the potential to provide a completely new telecom business model for both fixed and mobile network operators. Access independent IMS will be a key enabler for fixed/mobile convergence, reducing network installation and maintenance costs, and allowing new services to be rapidly developed and deployed to satisfy new market demands.“

Based as it is on IMS (which I wrote about in IP Multimedia Subsystem or bust!) this could turn out to be a project and a half. Saying that the “devil is in the detail” would seem to be a bit of an understatement when considering TISPAN.

A recent informative PowerPoint presentation about the benefits of NGN, convergence and TISPAN an be found here.

Roundup

We seem to have come a long way since the early days of WAP with HSDA now starting to deliver the speed of fixed line ADSL to the mobile world. Transfer rates are indeed important but high latency can be every bit as frustrating when using interactive services so it is important to focus on its reduction. The challenge with 3G is its limited coverage and this could cause slowness of uptake – as long as flat rate access charges are the norm and NOT per megabit charging as we have seen in the past. And boy, I bet the inter-operator roaming charges will be high!

However, bandwidth and service accessibility is not the only issue that needs addressing for the mobile Internet market to sky rocket. The platform itself is still a fundamental challenge, limited screen size and arcane menus to name but two. The challenge of writing of applications that are able to run on the majority of phones is definitely one the other major issues (I touched on this in Mobile apps: Java just doesn’t cut the mustard?).

I reviewed a book earlier this year entitled Mobile Web 2.0! that talks extensively about the walled-garden and protectionist attitudes still exhibited by many of the mobile operators. This has to change and there are definite signs that this is beginning to happen with fully open Internet access now being offered by the more enlightened operators.

Maybe, just maybe, if it all comes together over the next decade then the prediction in the above book “The mobile phone network is the computer. Of course, when we say ‘phone network’ we do not mean the ‘Mobile operator network. Rather we mean an open, Web driven application…” could just come about.

3 Comments | All, Internet, Mobile, Networks, Wireless | Permalink
Posted by Chris Gare

The curse of BPL

August 16, 2007

I am hesitant to put pen to paper to write about Broadband over Power Lines or BPL and Power Line Communications or PLC (maybe this should be Broadband over mains in the UK!) as I have no doubt that I am biased in my views and have been for a long time. This does not derive from in-depth experience of the technology but because I have been a radio amateur or ‘ham’ since my teenage years.

In the amateur radio world BPL is seen as a ogre that could have a major impact on their ability to continue their hobby due to interference from BPL trials or deployments. More on this later.

Today, the principle technology used to deliver broadband Internet access into homes is Asynchronous Digital Subscriber Line (ADSL) technology delivered by local telephone companies or ISPs collocating equipment in their switching centres. As ADSL is delivered over the ubiquitous copper cables previously used to deliver only traditional telephony services, it’s rollout has experienced tremendous growth over the last decade throughout the world.

However, ADSL does have some inherent commercial and technical limitations. For example, The further away you are from your local telephone exchange or central office the lower the bandwidth that can be delivered. This means that ADSL works best in high population areas such as towns and their suburbs. Even in the UK, there are still country areas where ADSL is not available because BT believes it is uneconomic or technically challenging to provide the service. For many years BT ran trials using wireless (that we would probably call WIMAX these days) to test the economics of providing Internet service to remote locations or caravan parks.

As ADSL can only be offered by telecommunications companies, whether they be old telephony providers or newer ISPs, this led to other utility providers wanting to get into the act. Water companies installed fibre optic cables when they dug trenches and canal and railway operating companies allowed telecommunications companies to run cables along their facilities.

We should also not forget our very own Energis (now Cable and Wireless) who started by providing wholesale backbone services by running cables along pylons. At one time nearly every electricity company had a telecommunications division.

This neatly brings back to Broadband over Power Line technology. The logic that drove the development of BPL is quite straightforward to understand. Every home is connected to an electricity distribution network so why should that not be used to deliver a broadband Internet service? This would mean that electricity companies could participate in the Internet revolution and create additional revenues to fill their coffers! Moreover, maybe BPL could be used to deliver broadband access to remote locations where ADSL cannot reach.

There is one thing about BPL that is clearly different from all the other technologies I have written about and this may seem a little strange. There are no IETF or IEEE technical standard for BPL although there are standards activities afoot. This makes deploying a BPL service a rather hit or miss affair.

Deployment is also challenging due to the fact there is tremendous variation in the electricity distribution networks throughout the world making standardisation a tad difficult. For example, in the UK hundreds if not thousands of homes are connected to a local substation where the high transmission voltages are converted to the normal 240 volt house supply. Hence it should be possible to ‘inject’ the broadband service in front of the transformer and deliver service to many houses at the same time which helps improve service economics.

In the USA the situation is quite different because of the distances involved. It is always more efficient to carry electricity at the highest voltage possible over long distances to reduce losses, so in the USA it is common practice to have the transformation to 110 volts done at the last possibly opportunity by placing an individual transformer on a pole outside of each home. This can wreck BPL service economics. However, this has not stopped many services trials taking place.

BPL technology

A BPL service can offer similar bandwidth capabilities to ADSL in that it supports an 256kbit/s up stream and up to 2.7M/bit/s down stream,. It achieves this by encoding data utilising the medium and shortwave spectrum of 1.6 to 30MHz or higher. In-house modems connect back to the head-end located at the substation where fibre or radio can be used to connect back to a central office as used in wide-area Wi-Fi services ( see The Cloud hotspotting the planet). The modulated radio frequency carrier is injected into the local electricity distribution network using an isolation capacitor and transmitter can have a power of 100s of watts.

BPL modems use several methods of modulation depending on the service bandwidth required:

  • GMSK (Gaussian minimum-shift keying) for bandwidths less than 1Mbit/s
  • CDMA (Code division multiple access) as used in mobile 3G services for greater than 1Mbit/s, and
  • OFDM (Orthogonal frequency-division multiplexing) for bandwidths up to 45Mbit/s

Most modern BPL deployments use ODFM as higher bandwidths are required if the service operators are to compete with their local telephone companies ADSL services.

There are several organisations involved in standardisation efforts:

Consumer Electronics Powerline Communication Alliance (CEPCA): A PowerPoint introduction to the activities of the CEPCA can be found here.

Their mission and purpose is the:

  • Development of specifications enabling the coexistence
    • Between in-home PLC Systems
    • Between Access PLC Systems and in-home PLC Systems
  • Promotion of high speed PLC technologies in order to achieve world-wide adoption thereof.

Power Line Communications Forum (plcforum): A similar body to CEPCA with many equipment suppliers as members.

HomePlug Powerline Alliance (HPPA): This group focuses on home networking using home electricity wiring as the distribution network – as they say, “power outlets are almost everywhere someone might want to use a networked device at home.”

IEEE P1901: According to their scope description the P1901 project will “develop a standard for high speed (>100 Mbps at the physical layer) communication devices via alternating current electric power lines, so called Broadband over Power Line (BPL) devices. The standard will use transmission frequencies below 100 MHz.”

Powernet: The main project objective of Powernet is to develop and validate a ‘plug and play’ Cognitive Broadband over Power Lines (CBPL) communications equipment. Power net is a European Commission project.

Side effects

With other postings about communications technologies I guess I would go on to say that although there is much work to be done, BPL is a complimentary technology to ADSL and it has its place in the Internet marketplace. My commercial reservations are quite strong however in that it is difficult to see how BPL can effectively compete with the now ubiquitous ADSL utilised by every local telephone company on the planet. Maybe there are niche markets where BPL could work and these would be geographical areas where ADSL cannot reach – yet.

However, as I indicated in my opening paragraph there are other concerns about BPL that are not encountered with any of the other ways of providing Internet service to homes whether they be delivered over wires such as ADSL or wireless such as Wi-Fi or WIMAX.

BPL has a dark side which I believe to be unacceptable and could prevent other legitimate users of the shortwave radio frequency spectrum to pursue their interests and hobbies without interference.

Interference is the issue which can be better understood by looking at the following video of a BPL service trial currently taking place in Australia.

BPL interference is causing problems in other countries as well, even the USA, where the Amateur Radio Relay League (ARRL) the body that represents all US radio amateurs has been forced into legal action in May 2007: ARRL Files Federal Appeals Court Brief in Petition for Review of BPL Rules

Also in May, the US Federal Communication Committee (FCC) has called for a BPL manufacturer to show that it complies with its experimental licence due to interference complaints – FCC Demands Ambient Demonstrate Compliance with BPL License Conditions

To quote the ARRL: “The Commission’s obsessive compulsion to avoid any bad news about BPL has clearly driven its multi-year inaction,” the League continued. “Had this been any other experimental authorization dealing with any technology other than BPL, the experimental authorization would have been terminated long ago.”

Many amateurs see BPL as the biggest threat to their hobby that they have ever been seen.

So why should there be this level of interference from BPL?

It might be good to start answering this question by looking at ADSL as this does not have any major interference issues despite its deployment in many millions of homes. ADSL is delivered into peoples homes via the copper telephone line. This cable is not just a single copper cable as it might have been in the early 19th century but rather it is a twisted pair.

A twisted pair cable is like a rather crude coaxial cable. It is balanced in that the signal flows forward through one wire and returns through the other. This means that the bidirectional signals cancel each other out and the cable does not radiate the signal it is carrying to the outside world. Twisted pair cable are not as lossless as coaxial cables so there is a little loss but it is quite small for the length of cable usually used to connect a home to a telephone pole.

In general ADSL has been immune from creating interference because of the use of twisted pair cables. Imagine the consumer furore that would occur if there was was interference from ADSL to FM or TV services it does work.

It’s interesting to remember that cable companies also use broad band RF encoding but as services are delivered using high quality coaxial cables or fibre there is generally no interference (The tale of DOCSIS and cable operators).

On the other hand, electricity power lines that brings electrical power into houses are not shielded and are not twisted pair. They are standard three or four core cables that we are all familiar with when we connect our kettles to plugs although they are of a heavier gauge.

BPL transmissions are spread over the shortwave spectrum with a head-end power of possibly 100s of watts and the lossy distribution cables effectively act as an antenna or aerial so the wideband BPL signal radiates quite effectively over a wide area causing the not inconsiderable interference as seen in the video above.

Surely, the regulatory bodies such as OFCOM or the FCC would not allow a service that significantly interfered with other spectrum users to go ahead – would they? That is not so easy to answer today as it would have been a decade ago when anti-interference regulations were very strong. Nowadays, in this commercial world we live in, there is far more flexibility given if there is a potential commercial benefit. For example, even in the UK the old guard band (allocated unused spectrum between services to provide isolation) have been sold off for use in picocell GSM services as discussed in GSM pico-cell’s moment of fame .

The level of interference from a service such as BPL would not – could not – have been tolerated a few years ago when everyone used the shortwave bands for entertainment. But in this modern ‘digital age’ shortwave seems an anachronism and who really cares if it not usable…

At least two groups of individuals do and they are radio amateurs and short wave listeners. BPL vendors and service providers and have attempted to suppress their criticisms of BPL by what can only be described as a sticking plaster solution. This solution is to put filters on the BPL transmitter so that notches are inserted in the broadband spectrum to coincide with the amateur bands.

However the general consensus by amateurs who have been involved in notching trials is that they do indeed reduce interference but not by a sufficient amount for workable co-existence.

Another concern is that BPL is not just used for the provision of Internet access services but it is also possible to buy modems to provide in-house LAN capabilities in competition to Wi-Fi. This could be a another worrying source of interference to shortwave services. Bearing mind there is no filtering in a mains or power socket, the use of a BPL modem in one house will radiate in all homes connected to the same substation.

Roundup

I really am unable to see any real benefit in this technology when compared to cable operator DOCSYS or telephone ADSL delivered Internet services whose access infrastructure is designed for purpose. Just slapping a broadband transmitter on a local electricity distribution network is crude and is definitely NOT fit for purpose – even if filter notches are applied.

If the electricity industry redesigned their supply cables to be coaxial or twisted pair, which in practice is not really technically or commercially achievable, then the concept may work.

I doubt that BPL is viable in the long term and my view is that it’s use will fade with time. In the mean time if I am asked for a financial contribution to fight BPL, I reckon I would dig deep into my pockets.

One example of one of the up and coming trials is TasTel in Hobart, Australia, a partnership between Aurora Energy and AAPT who say they have a unique service. To quoute their web site:

“Because BPL is brought to you by TasTel and eAurora, we can give you something nobody else can offer: fast Internet access and cheap broadband phone calls through a single service, on one bill which is sent to you electronically.“

Where have I heard this before – time move away from Hobart?

1 Comment | Internet, Living in the 21stc, Networks, Observations | Permalink
Posted by Chris Gare

Business plans are overrated

July 29, 2007

There more than element of obvious insight in Paul Kedrosky‘s recent post:

“Business plans are overrated. … Why?

… Because VCs are professional nit-pickers. Give them something to find fault with, and they’ll do it with abandon. I generally tell people to come to pitch meetings with less information rather than more. Sure, you’ll get pressed for more, but finesse it.

Presenting a full and detailed plan is, nine times out of ten, a path to a ‘No’ — or at least more time-consuming than having said less.”

– Paul Kedrosky, in the wake of the VC financing of Twitter, which has no business plan, no business model and no profits.

Leave a Comment » | Observations, Start-ups | Permalink
Posted by Chris Gare

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