IMTA Conference November 1999
SMR, Which Technology Will Win by Brian Seedle T.S.M.G
Abstract
Technology is moving faster than the man in the street can comprehend. Although the contemporary writers correctly predicted space travel, satellites and other technical wonders in the 1950’s, the cellular handset was never foreseen. Some technologies such as VHS, iDEN, have become household names, but there have been many casualties on the way that have been forgotten.
This paper analyses SMR from the user’s perspective, and then describes a mature open standard analogue radio network that is now established in over eighty five countries of the world.
Introduction
The last twenty years have seen an incredible explosion in personal communications systems. Today, our products are complex to design yet appear simple to the user. They take many years to develop from the first concepts to marketable products. Often, by the time a new technology has reached the marketplace, the market assumed in the original business plan has dramatically changed. Competition sometimes arises from unexpected area’s that were not foreseen in the original business strategy. This may result in a complete turnaround in the ability of that enterprise to make any profits. There are many businesses involved in the supply chain, from the manufacturer, the network operator, the service provider, the dealer and the end user (now the regulator also wants a piece of the action). If any one of these entities cannot prosper, the whole will not survive. This was the fate of the first U.K digital cellular network - Telepoint, despite an investment of more than $120 million. Telepoint attempted to develop its low cost low tier network at a time when cellular prices were falling. The new system took years to develop. By the time the Telepoint had reached the marketplace, the existing cellular handsets had reduced prices through economy of scale and Telepoint could not compete. Within 12 months, Telepoint was dead.
We are all drowning in technology, yet starved of understanding
The expansion of cellular industry continues to exceed all predictions and terminal units are truly in mass production, driving down prices. As soon as any writer attempts to measure the number of GSM(PCN) handsets in the world the number is out of date (but at 30th October 1999 – 2.30p.m the number exceeds 200 million). In today’s ‘developed world’ radio communications markets, other technologies including SMR are measured against cellular products. Unless a competing technology can offer a clear marketing feature, or price advantage to the user, that technology will struggle to succeed.
It is not always the better technology who wins. Many other factors define if a particular solution will succeed. A example can be drawn from the VHS/Betamax video standards. Betamax was the technically superior system but was a proprietary Sony standard. VHS was licensed to many manufactures. The customer was presented with choice and competition, VHS prices dropped, and sunk Betamax without trace.
The only issues visible to the end-users are reliability, speech quality, price, battery life, style. (and later coverage)
In evaluating the needs of users, the industry must heed that mobile communications is not the primary business of SMR users. Rather it is just another tool to help them efficiently and effectively run their company. Equipment must be easy to use at affordable prices. Users do not care about the technology. The only issues visible to users are reliability, speech quality, size, price and battery life. (coverage becomes important after the sale).
The regulator is now mandating that SMR systems are spectrum efficient. This naturally leads down the path of some kind of trunking for our modern networks. The trunking concept is not new: it was first developed in the 1970’s to improve the use of this finite resource. When channels are scarce and traffic is high, operators need to maximise the use of the spectrum while maintaining the grade of service. The modern radio trunk technology addresses the spectrum issue and at the same time provides a platform for a wide range of facilities for users. (Spectrum efficiency is of advantage only to the regulator and the network operator who needs spectrum to offer services to the end user). Modern trunked networks accommodate an extensive menu of speech and data call types, which can be connected over a wider geographical coverage area than most conventional SMR mobile radio systems.
Evolution of new technologies
Beware ‘experts’ predicting the future!
In Europe, the radio industry can call upon an army of consultants to prepare
reports and make presentations on the future of the industry. The record of
their success in Europe is however not good –
Quotes from Telecommunications analyst’s papers taken from previous
European conferences.
(1992) The global market for GSM will reach 15 million by the year 2000
WRONG – There are now 200 million phones sold (Oct 1999).
(1989) The UK market for MPT1327 will reach 350,000 by 1992
WRONG – The correct number was ~ 35,000
(1989) Data is expected to form 30% of the activity on PMR and PAMR networks
by 1992
STILL waiting
(1999) Today most wireless services revolve around the provision of voice
based services. This will change as data services increase.
MAYBE!
These are only a small sample of the facts and figures on which million dollar deals have been placed. Our industry is so complex that it is a very brave person who would make any predictions today.
Which Technology Wins! – It is not just the technology that wins but a combination of technology, right time, right place, product, price, marketing ….the list goes on and on. As an example - the present financial dilemma around the satellite-based networks demonstrates that even the big boys sometimes get it wrong. If the business plan truly has failed, its catalogue of errors, so visible with the benefit of hindsight holds lessons for us all. Throwing money at the problem is no solution.
The dominant contributor to the rapid expansion of the cellular networks in the U.K was to give the terminals free. Today the dealers pay you to take handsets away. Of course we know that the capital cost is built into the monthly tariff. We are now seeing exactly the same phenomena in digital television. The operators in the UK tried for many months to sell the set-top decoders without making any market penetration whatsoever. As soon as the decoders were free, digital TV has seen an exponential expansion.
SMR Versus Cellular
SMR pre-dates cellular. While cellular was in its infancy, SMR systems were adapted and developed to offer some cellular features in order to compete and maintain the SMR customer base. More recently in Europe, handset manufacturers have styled SMR products to be indistinguishable from cellphones. This may be a mistake because users will have an expectation that the SMR and cellular product are the same - indoor coverage, 100 hours standby…………… coverage is not noticed until after the sale.
A completely opposite tactic is to emphasise the features SMR has to offer that can never be rivalled by cellular. These include –
Calls to groups of users
Very fast call set-up
Dispatcher operation
Emergency pre-emption
A more complete list is detailed in Appendix I
In Europe the population density favours cellular. The number of SMR users
has therefore only grown by a relatively small figure in the last ten years.
The number of SMR users per head of population is only a quarter of the SMR
penetration in North America
Migrating Users From Their Existing Radio Systems
Tactic #1
Persuade the users that the new features, speech quality, coverage, battery
life are irresistible - EVERYONE WANTS ONE
In order to attract users to change quickly, the advantages must be overwhelming. As an analogy consider the migration from vinyl records to CD’s. There was a clear advantage in CD’s of superior music quality and smaller size, but players were initially expensive and required mass production to achieve economy of scale. (The music program makers also took the opportunity of raising the price, an issue that has never been redressed). However this migration took over 15 years.
In the UK the cellular operators wanted to move their analogue TACS users to GSM(PCN). They tried free swaps, and other incentives, but the users reply was just - ‘if it ain’t broke, why change it’. The users could not see any difference between his existing phone and the digital one (except in many cases the digital phone gave worse coverage).
Tactic #2
Switch of the existing channels – NO CHOICE
The cellular operators will have this problem at some time in the future when they attempt to de-commission the TACS Networks. (The UK government has announced that their terrestrial analogue television will be switched off within ten years – a very bold statement)
Migrating users from traditional SMR to digital trunking
Although conventional SMR has not seen the extraordinary growth of GSM and iDEN, it has maintained its users. The failure of public trunked networks and cellular to remove traditional SMR from the scene indicates that its combination of low costs, good local control and operational simplicity is still in demand.
MPT 1327 Trunking Standards
MPT trunking is now an established and mature technology around the world. Manufacturers in this market recovered their development costs at a time when competition was not so severe. The cost of MPT infrastructure and terminals can now meet the most stringent financial targets. The capital cost for complete MPT base station site (controllers, R.F base stations, R.F combining, antennas) currently stands at less than $100 per user. Portable terminals can be bought for less than $400. Small private organisations needing radio communications and only a small chequebook find MPT very attractive. Until digital SMR technology finds the economy of scale to reduce prices, MPT will continue to find new markets. Of course if any new technology is highly complex, potential manufacturers may not be prepared to fund the enormous development costs. If this restricts the number of global players, competition may be stifled, and prices remain high. This ‘chicken and egg’ situation where low prices require mass markets, but mass markets require low prices must be broken by reaching a critical mass.
MPT1327 boasts a choice of 20 infrastructure manufacturers and at least 18 terminal manufacturers around the world. Customers have choice, aggressive competition keep prices low and quality high.
In areas of the world where the fixed telecommunications structure is very limited or non-existent, MPT1327 systems have been a great success. Examples include oil pipelines, rail routes and road transport routes. Many of the roadside emergency telephones in remote areas in the Far East are in fact modified MPT terminals.
Data developments in MPT1327
There is a wide difference in the take-up of data around the world. In some countries such as South Africa, the data transactions account for 60% of the control channel loading. This is a mix of dispatcher forwarding of jobs and GPS data for vehicle tracking
Taken as a whole, the type of data user that was expected, has not materialised. What is most popular is the forwarding of small data items from units that collect information remotely. The most widely used application is GPS vehicle location. It is possible to procure the MPT radio, GPS receiver and antenna for less than $500.
What has not significantly materialised is the transmission of long strings of data. Maybe this situation will change through new recent interest in EMAIL and the Internet.
The MPT1327 standard only prescribes how the data messages are formatted at the air interface. There was not corresponding access interface protocol. In 1994 however an access interface document was produced called MAP27. This enabled data applications to interface with compliant radio terminals independent of radio manufacturer.
Migrating Users to MPT1327
There are still hundreds of thousands of users in Europe who use conventional SMR dispatcher radio systems and Community Base Stations. There is a benefit if existing channel resources can be shared during the transition from conventional to trunking. At least one MPT manufacturer has a facility whereby a traffic channel can be shared with a CBS or conventional channel. The system can be programmed to statistically favour either the trunking or conventional use of the channel. As users migrate the odds can be adjusted away from conventional use. The UK regulator now has a policy to migrate CBS users to trunking. Incentives from the regulator include many kinds channel swaps and bartering.
Providing Bridges to MPT1327
It is very desirable if an MPT network can bridge to other systems. Bridges and interfaces are known for the following –
Smartnet Trunking
DID Exchanges
Internet EMAIL server
X25
Conclusion
In evaluating the future for MPT1327, the public and private networks must be considered separately. The operation of any public Network is fundamentally different to a private system. In a public network, priority or emergency access is difficult or impossible since relevant users will demand performance that statistically cannot be guaranteed. In addition there is always an impact on other users who may be the victim of pre-emption. One of the first generation U.K networks failed to restrict emergency access and soon paid the price. Users soon learned that if a call was queued during busy periods, an emergency call got though. It was not long before the initial step of a normal call was bypassed, so the whole pre-emptive mechanism was doomed. The operation of first generation trunked networks have certainly provided the know-how and experience that will have a direct bearing on the topology and management of the latest generation of SMR networks.
Manufacturers have often been criticised that the styling of traditional and trunked PMR terminals have always been different (and substandard) to that of cellular. This has however differentiated the products. If the manufacturers adopt ‘cellular’ like styling on public networks, there is a danger that the users will expect the terminal to behave like cellular both in terms of operation and coverage.
In recent years, markets for regional systems have been maintained, and, although MPT1327 was never designed for the emergency services, some very successful networks have been built.
MPT1327 equipment has developed wide and varied applications through its rich menu of facilities. It is unlikely that any new large public networks will be installed in Western Europe, but private systems with a coverage area of a small number of sites are still in the manufacturer’s order books, replacing old conventional SMR systems.
Outside Western Europe the market continues to be stable. Cellular still cannot meet constraints where fast call set-up and prioritising of calls is mandatory.
In many areas of the world, the local environment restricts choice. Requirements are often –
Lowest cost per user
Restricted or non-existent fixed links to connect the sites
Limited engineering staff/expertise
Varied use including emergency and ‘cellular like’ services
Wide choice of manufacturers equipment
Technology step is modest from conventional systems
Today, only MPT1327 can meet these criteria. Unless digital trunking reaches the critical mass where the cost of the equipment will substantially fall, MPT1327 will continue to be an important and useful technology for many years.
APPENDIX I
MPT1327 Standards
The MPT1327 specifications actually comprise four documents – MPT1327 defines the message and modulation format: MPT1343 is an access interface document for terminals: MPT1347 is an access interface for base stations: MPT1352 is a test document for terminals.
The MPT specifications were not designed as an international standard. They were developed for the U.K market to make efficient use of a block of spectrum released from the closure of VHF television transmissions. The British Ministry of Posts and Telecommunications (now the U.K Radio Agency) sponsored the drafting of the MPT Standards through the formation of the MPT1327 Drafting Group. This group was represented by manufacturers, and other professional bodies representing particular interests, including transport, fuel and power, and later, Network Operators. Because MPT1327 is an open standard, equipment from different manufacturers can operate seamlessly – both terminals and infrastructure.
The Standard was first published in 1988, although a compliant system was
in place on the British Telecom tower as early as 1986, operating under the
name ‘Baselink’. At this time other systems using a very similar
protocol were installed on British Rail. These early networks imparted confidence
that the MPT protocol would work.
The MPT Standards were revised in 1991 and saw a moderate expansion in 1996
where some features were added. It is a tribute to the original drafting group
however that a radio terminal conforming to the 1988 Standard would remain
compliant today.
Electronic copies of the Standards are available on the Internet from several sources including www.open.gov.uk/radiocom/rahome.
The fact that this was a truly open standard was a catalyst for its rapid growth. A variety of manufacturers’ equipment became available for both network infrastructure and terminals. This competition stimulated quality, functionality and most importantly, price. As early as 1990, MPT systems had been commissioned as far as Australia and Siberia. By 1993, regional and national systems were in place in Europe, including Germany, France, Netherlands, Italy and Spain. In the global arena, regional networks were installed in most continents. Today, over 84 countries are known to have installed MPT systems. At least 16 independent manufacturers offer MPT infrastructure and 18 companies manufacture MPT terminals.
Progress of MPT 1327
When the MPT Standards were first published, manufacturers were under pressure to roll out their networks. The first generation MPT networks offered simple half duplex speech calls, single site or wide area: single site group calls: limited PSTN/PABX: and status messaging. Further development followed and by 1992 most networks and terminals offered a wide range of features including –
Call Types
Individual Speech Calls to
Mobile subscribers
Line connected services – PABX/PSTN
Call priorities, normal high, emergency
Group Calls
Single Site
Wide Area Multi-site
Call Diversion
Call Transfer
Include Call
Voice Mail
Full Duplex Calls
Pre-emptive emergency calls
Late Entry Groups
SST’’s and MST’s
Channel Segregation
A number of variants of MPT have been employed in Europe. These differences are small and may be accommodated by configuration of equipment during installation.
Number Schemes and variants to MPT1327/43
• MPT1343 (Mandatory in UK BandIII frequency band)
•
ANN
•
TRAXYS (Holland)
•
REGIONET43 (Germany)
•
PA2424 (France)
•
CPS, CPSX, CPSXG (China)
In areas of the world where cellular is well-established and good telecom’ links are in place, it is now far more difficult to attract new trunking business. Recently, there has been a move by manufacturers to provide features that will differentiate trunking from cellular. Manufacturers have redirected their marketing, and now tend to target security and emergency services, docks and harbours, transport, and long distance remote routes. The features where MPT trunking can have a strong advantage over cellular are –
Instantaneous call set-up
The fastest call set-up speed for MPT is actually just over 200mS for groups
and just over 400mS for single prefix speech calls.
Prioritising of calls
Priority and Pre-emptive emergency access is essential in security and emergency
environments.
Sharing of channel resource with other systems
A traffic channel can be shared with a conventional channel. (for example such
a channel may already be in use for a community base station). The system can
be programmed to statistically favour either the trunking or conventional use
of the channel. As users migrate, the odds can be adjusted to or from conventional
use.
Site backup power
For Emergency services, 48-hour backup is often essential
Pooled Channels
Pool Channels have identical frequencies on two or more sites where the coverage
pattern overlaps. The network may be configured to either a) only use the channel
at one of the sites at any one time or b) always attempt to use the common
channel frequency for calls between the sites. Messages generated when the
PTT is pressed by the user switches off the remote site transmitter.
Groups and wide area groups
Wide area groups encompass a specified number of sites. Wide area groups allocate
a traffic channel on more than one site. (This not spectrum efficient). The
Network keeps a map in its database of the sites to be allocated.
Open Channel Working
This is barred in the UK BandIII Networks. The feature is specified in Regionet43
in Germany. In some areas of the world it is essential. This is s terminal
feature.
Dispatcher operation
Line connected dispatchers were designed into the first generation MPT networks.
By far the most popular today is radio-connected dispatcher.
Virtual User Groups
Virtual user groups are groups of terminals that have exclusive use of a number
of traffic channels. Independent Network Operators may share a single control
channel.
Local PSTN
A PSTN interface at a site (or group of sites) is a very important feature
in countries where fixed telecommunications is sparse or unreliable. The Network
uses some criteria such as number of dialled digits to determine if the call
will be routed to the local connection or the central call router.
Selectable Individual Groups
The user can enter a group identity into the terminal to define a new group
to which that terminal will belong.
Dynamic Regrouping
The Network has the ability to transmit a new group definition to a radio terminal
Remote Stun/Unstun
The Network has the ability to disable a radio terminal remotely.
APPENDIX II
TSMG Trunking Standards Maintenance Group – this group maintains the MPT1327
Standards.
When all traffic channels are in use, a priority call is queued ahead of normal calls, and a pre-emptive emergency call clears a normal call to free a channel.
If a radio is switched on when a group is already active on a traffic channel, the control channel will send messages so that the radio joins the group.
SST’s Single Segment Transaction. Allows the transfer of up to 184 bit of information using the control channel only.
MST’s Multiple Segment Transactions. Concatenates SST’s together to transfer up to 184 bytes of information using the control channel. Must be used with care since MST’s have a great impact on control channel loading.
Channel segregation makes a different number of traffic channels available depending on the identity of the calling or called party. This is another way of controlling the priority calls in the system.
Manufacturer of MPT1327 Infrastructure
ADI Alcatel Aselsan Etelm
Forward Fylde GEC/Marconi Key
Midland/Intek Motorola Nokia R & S
Rohill Simoco OTE Tait
Vigor Zetron
Manufacturer of MPT1327 Terminals
ADI Alcatel Atelsan Bosch
Electronica-Dizain Icom Kaviciom
Kenwood Key Kyodo Maxon
Midland Motorola Nokia OTE
Rohill Simoco Tait Talco
Speaker - Brian Seedle
EMAIL - bseedle@aol.com
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