A STUDY OF JOINT EQUALIZATION AND TIMING RECOVERY SCHEMES

Abstract

The telecommunication udminti4thati.on a/ mo'St count es cure engaged i.n digi.tazing thein tnansmon and switching as a hey 'step towwtda e'stuht 'shing an £ntegnated digitat netwon't [1J. The pne'sent netwokk can't's o a mix o cabte (ji.hei. optic and coaxiat cabte), aattetite and Zine-o/-'i.ght (mic owave) tadio 'sy'stem's. Due to the ewLge eeaee i.nt'.odueti.on off, digitae switching in the ewt y 1970', the m2enowave di,gi.ta2 radio has been gaining i.mpontanee as a tnanami,a's on medium ion. digitae communication [13. The maj oh advantage o mi,c,%owave digitae n.adi.o oven opti.ca2 /i.hen i,6 its tower i.natalation cost and it's prima) y advantage ove't satteeite tnanomiaoion i ss i.to much smaeee/L ptopagati.on decay. The intkoducti.on o di.gi.tat radio 'sy'stem's can he 'succeaa~ut onty i.~ they meet exi.ating tnanami'sa.ion pen~anmanee 'standcucda and the 'spectra( eci.enei.e's ate compati.hte with those of theivt analog counten- pcuct's. Thus, there is need fa't the ecient utit zatLon o the uvai.Pabte 'spect4um. T hi.'s has ted to the de'i.gn o digitat radio o y'stem's empto yi,ng highly spect/Lat eUicient modutation technique's [2]. The .i.nat genen,ation digitae radio 6y stem, .intnaduced 6cmcety oven a decade ago, used tow-tevee modulation's such u's a 2- and 4-tevet phase 'shit keying (PSK). Shontt y a~teic, 'sy'stem's were 2ntkodueed u'i.ng 8-PSK [3] and 9 eevet quadrature pcvLt at nehpon'se 6ignaing (9-QPRS) [4]. Thi.6 was ottowed by 'syatevn's wing high tevet quadrature ampt.itude modutati.on (QAM). Speccatty 16-QAM [5] now enjoys widespread u'se and 64-QAM [6] i.'s becoming common place. Moteoven., the lea'tihtitity o 256-QAM [7] and even 1024-QAM as candidate's far, modutation tune being acti.vet y inveati.- guted ...