digital enhanced cordless telecommunication(dect), the technology originated as a european initiative is now rapidly conqueringthe telecommunications world. the benefits offered by this high quality accesstechnology are recognized by more and more users, regulators, standardizationbodies, network operators, and equipment manufacturers. dect has provenmultiple applicability as a network access in residential, business and publicenvironments showing easy mobility, speech quality comparable to wirelinetelephony, a high level of security through advanced digital technology andencryption, allowing for high subscriber densities, flexible bandwidthallocation, multiple service support, cost competitiveness, flexible deploymentand simple installation.
thedigital enhanced cordless telecommunications (dect) standard provides a generalradio access technology for wireless telecommunications, operating in thepreferred 1880 to 1900 mhz band using gfsk (bt =0.5) modulation.
decthas been designed to provide access to any type of telecommunication networkthus supporting numerous different applications and services. the range of dectapplications includes residential. pstn and isdn access, wireless pabx, gsmaccess, wireless local loop, cordless terminal mobility ctm, local area networkaccess supporting voice telephony, fax, modem, e-mail, internet, x.25，and many other services in a costefficient manner.
adect system comprises a dect fixed part (fp), utilizing one or more basestations (rfps), and one or more dect portable parts (pps). there is no limitto the size of the infrastructure as far as the number of base stations andcordless terminals is concerned. infrastructures using the dect technology cansupport traffic densities up to 10000 erlang/km2.
inprinciple the dect base standard (of which all parts are shown in table 1) onlycovers the “air interface” between a dect fixed part (fp) and a dect portablepart (pp), it provides a toolbox with protocols and messages from whichselections can be made (profiles) to access any specific type of network. inaddition to cordless, dect makes available the network specific services andfeatures (including mobility) to the user through the dect common air interfacetransparently.
it’smulti carrier, time division multiple access, time division duplex(mc/tdma/tdd) radio access method and continuous dynamic channel selection andallocation capability enable high capacity, pico-cellular systems, beingutilized even in busy or hostile radio environments. these methods enable dectto offer excellent quality of service without the need for frequency planning.dect makes efficient use of the assigned radio spectrum, even when multipleoperators and applications share the same frequency spectrum.
standardizedprofiles have been defined for e.g. generic access (gap; which is mandatory asa minimum requirement for all dect voice telephony equipment as from october1997), radio in the local loop applications (rap), isdn and gsm interworking(gip).standard profiles encourage dect equipment manufacturers to implementinterworking with the network in a harmonized way. this creates interoperabilitybetween dect equipment from different manufacturers and directs competitiontowards differentiation on non-technological features, providing consumers, andnetwork operators with the luxury to choose from a variety of standardproducts. standardization of interworking also allows for mass production ofsystem components, which in its turn provides significant cost benefitsenabling highly attractive price/performance ratios for dect equipment.
thenorth american personal wireless telecommunications standards pwt and pwt/e(tia) are based on dect. pwt and pwt/e provide the same services as dect; theyuse the same framing structure mac, dlc, nwk layer and identities but analternative modulation scheme and frequency allocation. the pwt operates in theus unlicensed band 1910 to 1920mhz. pwt/e is an extension into the licensedbands 1850 – 1910 mhz and 1930 - 1990mhz.