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10/5/2009
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M2M stands for machine-to-machine and implies two machines communicating with each other. Whilst at one level this could embrace a computer connected to a server it is generally taken to imply no human intervention. Thus a computer monitoring a remote sensor for, say, the management of a building environment would be M2M.
One of the network designer's watchwords. There is no point in introducing any element or feature into a communications network if it cannot be managed, i.e. brought into service, taken out of service, monitored for performance, updated etc.
TBA
An underground cable jointing chamber sufficiently large for a person to enter to perform cable jointing (splicing). They can vary from a snug fit for one to quite large structures, particularly very close to a telephone exchange (exchange manhole) in cities. The descent via steps is very often accessed via a small access chimney which then expands into the main chamber. Because of the danger of pollution and noxious fumes, gas testing prior to entry and other safety issues such as keeping someone above ground and roadworks guarding are paramount. See also vault.
Marketing for telecommunications
Marketing is about the way an organisation (or individual) matches its capabilities to the wants of its customers. The matching takes place formally or informally but a mis-match leads to failure. In the simplest market place the marketer and customer meet face to face. In more complex market places this is no longer true, so in practice all medium to large companies have a formal activity to overcome the problem. This formal activity is therefore concerned with the analysis, planning and control of the process of matching capabilities with customer wants. The matching process is often summarised in the four 'p's - product, price, promotion and place. They interact in what is called the marketing mix and the people who grapple with optimising the interactions form the marketing function. Marketing and selling are often confused: selling is a part of marketing concerned with persuading the customer to acquire the product or service. If the marketing is ineffective the sales force finds itself trying to sell what the company wants its customers to want.
The marketing mix varies for consumer and industrial markets and between products and services. Telecommunications is a very complex area with many segments of customer wants, of products and of services. The competitor for any particular service or product is not always another telecommunications company: for transporting large volumes of data, for example, it can range from broadcasters to couriers. The main lesson for network designers is that the technical design must be focused on a customer want at an acceptable price to the customer, and cost to the provider, rather than on what the technology can do.
Explaining what the technology can do to the marketing function so that they can interpret that into customer wants is a part of the designers role. The debate as to whether telecommunications is technology led or customer led is probably not one that will be resolved since they are interactive and the technologies are driven by non-telecommunication factors (such as IT and military R&D). Putting aside products and related activities such as systems integration and consultancy services the designer is well advised to remember that a network makes money by carrying traffic. An underutilised network does not pay for itself, an over-utilised network does not meet grade and quality of service expectations. When a network is extended or enhanced the traffic to fill it must not be far behind.
Book reference: Marketing High Technology Services. Colin Sowter. Pub: McGraw-Hill Book Company Europe, 2000. ISBN 0-566-08429-5.
See units and symbols.
One of the basic forms of networks.
A radio network where a number of nodes form a network without a designated base station and determine their own routing paths between nodes. A form of ad-hoc network but one where the nodes are generally not mobile and are stable over a long period. One use is for residential service with each node serving an individual residence and where each may route signals on to others depending on locations and atmospheric conditions. A similar application for emergency use has been deployed using the ad-hoc capabilities of Wireless LANs (IEEE 802.xx).
Two mesochronous digital signals are isochronous, asynchronous digital signals whose respective timing signals but no control on the phase relationship. (Bregni) See also anisochronous, asynchronous, heterochronous, isochronous, plesiochronous, and synchronous.
Short Messaging Service (SMS), Enhanced Message Service (EMS) and Multimedia Message Service (MMS) are standards for person-to-person (P2P) messaging over mobile networks. They have been developed and maintained under recognised cross-industry forums. With regard to their functionality, a clear line of evolution can be seen through the three standards:
• SMS enables mobile phone users to send short, plain-text messages to other mobile phone users
• EMS enables mobile phone users to send longer text messages, plus simple graphics and sounds, to other mobile phone users
• MMS enables mobile phone users to send formatted text messages of any length, plus graphics, photos, audio and video content, to other mobile phone users and to e-mail users.
EMS and MMS are standards being developed by the 3G Partnership Project (3GPP). They were originally proposed as two separate stages of evolution from SMS, with users being migrated first from SMS to EMS, and then from EMS to MMS. However many users migrate straight from SMS to MMS without passing through the intermediate EMS stage.
The principal features of the three standards are summarised below.
| SMS | EMS | MMS |
| Plain text, black only | Plain text, unlimited length, simple graphics and sound | Freeform text, colour, graphics, photos, audio and video |
| 160 characters max | Upper limit on message size | Unlimited message size |
| Uses the signalling channel | Uses the
signalling channel |
Uses IP based standards and Internet content standards |
| Messages can be sent to mobile phone numbers | Messages can be sent to mobile phone numbers | Messages can be sent to mobile phone numbers and e-mail addresses |
| Supported by nearly all GSM phones in current use, as well as other phones | Very low handset penetration | Zero handset penetration |
Source of table: Nokia and Ericsson.
Metropolitan area network (MAN)
A general description for a network serving a city. It arose from the use of local area networks (LANs) which were initially used for enterprise (company) networks but now also used in the home. Where traffic on a LAN has to communicate beyond the LAN it is connected to the outside world which is usually described as a WAN but where the connection stays within a metrpolitan (city) area it is sometimes referred to as a MAN. This is more meaningful in a North American context where cities can be hundreds of miles away from the next city.
Mobile Station Application Execution Protocol Environment, or MeXe, is a wireless protocol designed for use in modern smart mobile handsets. The aim is to have a standardised execution environment for applications, particularly for Intelligent Network and CAMEL (customised application for mobile network enhanced logic) services. MeXe buids a Java Virtual Machine in the handset and requires significant processing power as well as a strict security framework.
A friendly and rather imprecise term for radio frequencies above about 1 Ghz. The higher ranges are also known as millimetric waves as well as by their more formal classifications, such as super high frequencies (SHF) etc (see frequency spectrum). Whilst widely known for cooking using high-powers concentrated in a few tens of cubic centimetres they are also widely used for communications over long distances.
Microwaves can be transmitted by radio or over short distances using special transmission lines called waveguides.
The most commonly used forms of microwave radio are in satellites for communications and broadcasting and in point-to-point terrestrial microwave systems. The former requires a large dish antenna for the ground station to permit 2-way transmission for multiple channels due to the corresponding small antenna at the satellite, the wide bandwidth of the signals, the high transmission-path loss due to distance and the need for accuracy in the overall signal due to its multiple component signals. Satellite broadcasting uses much smaller receiving antennas as it is unidirectional and the video signals can be more tolerant of high path losses. Point-to-point terrestrial systems vary from small dishes mounted on poles and buildings for short-links (a few km) to large multi-channel systems between cities where repeaters are required every 30 - 40 km and the dishes are mounted on large masts or towers.
In the computer industry, middleware is a general term for any programming that serves to glue together, mediate between, or enhance two separate and usually already existing programs. Middleware is therefore just software. Any piece of software, including any application, immediately becomes middleware as soon as it becomes used by any other piece of software or application. Middleware therefore appears in many places - terminals, applications, networks - and because of that it can mean different things to different people depending on context (hence sometimes called muddleware).
Middleware is at different levels:
- High level architecture
- Detailed architecture/design
- Building blocks (database/directory services, call-control, operating systems)
- Specification
- Product/code (e.g. Orbix)Classifications of Internet middleware include:
- Distributed computing environment (DCE)
- Object request brokers (ORBs)
- Remote procedure call (RPC)
- Distributed transaction processing middleware
- Database connectivity middleware
- Message oriented middleware
Many advances in telecommunications have started off in the military arena. There are a number of reasons for this. They include: the need for mobility, the need for network redundancy when key parts of a network might be seriously degraded or destroyed and the vast amounts of R&D expenditure devoted to the area. A few examples of innovations that have migrated to civilian use include: the Internet, communications satellites, including the Global Positioning Satellite; ever decreasing sizes of wireless devices; spread-spectrum techniques. The computer itself has its origins in the decoding of intercepted HF radio signals from the German High Command in World War 2. What is happening in military communications therefore matters to us in that it helps us see some future aspects of civilian telecommunications, albeit through a fog.
A measure of the traffic carried by a network. One call for one minute is one call minute. It is more often used as a financial measure rather than a design criteria for teletraffic, where the call second, calling hour and Erlang are more meaningful.
A loose term. Widely used by lay-people to mean their mobile phone/mobile handset (more technically called a mobile station). It is more generally meant to mean telecommunications on the move with implied nomadicity. As the cellular industry was the first to meet mobile telecommunications needs, it is frequently taken to mean mobile networks as a synonym for cellular networks. Also see mobility.
In telecommunications mobility is associated with people, as personal mobility, and with a terminal as terminal mobility. It does not always equate to cellular networking although that is the common association. For instance, personal mobility can be met by the use of a calling card. Terminal mobility can imply that a terminal can be moved from one fixed network access link to another and still be recognised and provide access to all the user's services. For instance a laptop PC may be able to switch between a cellular service and a WLAN depending on availability, service need, service contract(s) and tariff.
There can be many reasons for building a model of a system to observe and predict its behaviour. In general a model provides abstraction, focus, simplicity and clarity to help decision making and development. In the network area a model may be required because the size of the real network may simply be too large for measurements to be taken on it, or taking measurements may affect the performance of the network, or the network may not yet be built but some knowledge of its behaviour is still needed. In the business and financial area it may be desirable to carry out a set of "what if?" scenarios by changing variables to determine how viable certain courses of action would be.
Modelling tools vary widely. The spreadsheet is one well established method which can handle great complexity in the hands of skilled users. There are also many specialised tools. For example, the development of telecommunications service specifications can involve formal methods such as the service and description language (SDL) for which commercial computer programmes are available.
A contraction of modulator/demodulator. In the early days of computers when all networks were analogue there was a desire for the computers to communicate digitally. This was achieved by taking the digital signal and modulating an analogue signal then passing it over an analogue line, frequently a dial-up connection, and recovering the digital signal at the other end by demodulation. Widespread use of such modems started in the 1960's with bit rates as low as 300 bit/s. They were usually separate boxes at each end. The concept even led to low cost optical modems where a 2Mbit/s signal was converted to analogue optical over low-cost multi-mode fibres.
Direct digital links, especially for high-speed private circuits and consumer broadband links, have led to a decline in modem use. However, modems are still in regular use in the early part of the 21st century, notably built-in to computers for accessing the Internet at 56kbit/s over dial-up connections over access networks that are still analogue (mostly copper pairs) even where the rest of the network is now largely digital.
If an electromagnetic wave is to carry information it must be varied in some way and in a way that the information can be recovered later. The process of varying the wave is called modulation and the process of recovering the information is called demodulation or detection. There are three main ways of modulating a sinusoid or continuous wave: amplitude modulation (AM), frequency modulation (FM) and phase modulation (PM). FM and PM are closely associated.
Many variants exist especially for pulses or non-continuous waves, including shift keying for all three forms (ask, fsk and psk respectively), pulse amplitude modulation (PAM), pulse code modulation (PCM) and complex forms of digital modulation making simultaneous use of more than one of the basic parameters and intended to increase the bit rate compared to the symbol (or Baud) rate.
In general the three main modulation types can be two-level representing the two binary states or multi-level. In quaternary systems (four level) each level represents two information bits, 8 way, 3 bits , 16 way 4 bits and so on.
Gordon Moore made his famous observation that the number of transistors on an integrated circuit would double every couple of years in 1965. He was then with Fairchild Semiconductors which subsequently became a foundation of Intel and the observation was made just four years after the first planar integrated circuit was discovered. The press called it "Moore's Law" and the name has stuck. Intel expects that it will continue at least through to the end of the first decade of the new Millennium.
Some observers have noted that a projection of Moore's law would take clock speeds in 2018 to over 53Gbit/s and at some point achieving such high speeds will take the problems to be overcome to the atomic level at which point alternative means to traditional silicon fabrication may be required.
A very small device that contains a sensor, some computing power for processing and wireless connectivity for communicating. It is one of the outcomes of the smart dust programme of DARPA and makes use of nanotechnologies such as MEMS. Military applications include the dropping of sensors on to a battlefield to monitor enemy deployments. The motes then communicate with each other and relay partially processed information back to a base station. Civilian applications could include heating, ventilation and air-conditioning (HVAC) monitoring of buildings. Whilst press coverage has them only one or two millimetres cube, at present they are somewhat larger. The origin of the name is not clear but Buddhist dust-motes (param-anuh) is one possibility although the use of mote as a small particle is used in other areas (e.g. a small piece of seed left as an imperfection in cotton).
Multimedia (sometimes hyphenated)
A general term used to describe services that combine various aural and visual characteristics. It can embrace speech, music, text, fixed and moving images, video etc.
Multimedia Message Service (MMS)
SMS (see messaging) is very limited in terms of the 160 character text-only content that can be carried. MMS extends the richness of messaging by adding pictures, captions, sounds and moving images, particularly for mobile use. See Mobile multi-media services, BTTJ, Vol 21, No3.
There are several multiple access technologies used for transmitting information:
Carrier sense multiple access (CSMA) see Ethernet and
• Frequency Division Multiple Access (FDMA)
• Time Division Multiple Access (TDMA)
• Code Division Multiple Access (CDMA)
Taking these in turn:
• Frequency Division Multiple Access (FDMA)FDMA divides the bandwidth into separate channels and each signal is put on to a different frequency, so there is one channel per user. Each channel has a uniform section of bandwidth.
FDMA is mainly used for analogue transmission, whilst it can carry digital information it is not considered to be an efficient method for digital transmission. 1G mobile used FDMA.
• Time Division Multiple Access (TDMA)
TDMA assigns a certain portion of time (timeslots) on a designated frequency to each channel.
• Code Division Multiple Access (CDMA)
CDMA digitises data and spreads it out over the entire available bandwidth using a unique spreading code. Each channel has a unique code associated to it, so channels can share the same frequency. Between 8 and 10 separate calls can be carried in the same channel space. This can be a more efficient user of the bandwidth in some circumstances. CDMA is a form of spread spectrum.
Multi-protocol label switching (MPLS)
MPLS (Multi Protocol Label Switching) is now accepted as the best way to provide different classes of service over an IP network. In simple terms, it does this by converting a routing network into a switched network for a particular communication.
See also Multi-protocol label switching as the basis for a converged core network, BTTJ, Vol 22, No 2 and Traffiic engineering, BTTJ, Vol 18, No 3.
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