7/17/2019 Comparison Papers

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Paper 1: Uses adequate pair of DC test signals for detection of Tx non-idealities

• Envelope detector used is a Class- B Biased NM! D"na#ic $angeCo#pressor

•  T%e polarit" of t%e po&er levels on using t&o test signals for eac% esti#ation

of i#'alance para#eter is used as a (uctuation of po&er level test &%ic% is

detected '" a co#parator instead of a #ulti-'it )DC

• DC o*set co#pensation   +, .ain #is#atc% co#pensation   +, P%ase

Mis#atc% Co#pensation

DC o*set Co#pensation:

•  T%e polarit" of  P1− P

2  is detected '" an envelope detector and is used as a

test for /nding opti#u# C  I  using binary search algorithm. T%e

#agnitudes of eac% output are t%en co#pared using sa#ple-and-%old 'ased

co#parator0

• !i#ilar process is repeated for pat%

• No require#ent for t%e detector to 'e linear as onl" polarit" is used as a

condition0 T%e non-linear propert" auto#aticall" co#presses t%e d"na#ic

range of t%e signal essentiall" ta2ing t%e place of varia'le gain circuit0

 

Paper 3: No training sequence

• )daptive 4M! co#pensation independent of t%e statistic of t%e trans#itted

data

• !eparate treat#ent of t%e t%ree existing errors:

5i6 uadrature Error ' α ' 

 T%e envelope of o'  (t )  is squared to o'tain  EQ

2 (t )  

Mean is o'tained after #ultiplication &it% signu# function i0e &enor#ali7e t%e co#plex signal0

5ii6 $esidual Carrier ' χ  x '   and ' χ  y ' 

)fter o'taining  Ec

2 (t ) 8 &e #ultipl" '" sign( x (t ))  and sign( y (t ))  

to o'tain residual errors Ɛ x  and Ɛ y  respectivel" as

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5iii6 .ain +#'alance Error ' δ ' 

+#proved Tec%nique:

  )n adaptive setting of t%e reference squared envelope level usingsi#ple 4M!

!olution converges in a'out 3999 iterations for eac% error

  Non-linearities in the ED will be taken into account

Paper : ) co#plete o;ine tec%nique for co#pensation

• 4M! )lgorit%# is used for co#pensation

• )daptation of .ain and P%ase +#'alance

)daptation is co#plete &%en all < p%ases give t%e sa#e output ve  fro#

t%e ED0Error !ignals are di*erence 'et&een test signal outputs in pairs:

Paper <:

•

Co#pensates 'ot% frequenc" and non-frequenc" dependent co#pensationpara#eters

• Uses recursive algorit%#s to esti#ate t%e i#pair#ents fro# t%e

instantaneous po&er if t%e trans#itted signal

• Esti#ation and co#pensation are perfor#ed in t%e regular operation #ode

• Convergence )nal"sis is covered

• =urt%er convergence )nal"sis "et to 'e understood