8/18/2019 4.LTE Overview 69
1/62
LTE Overview
Course Objectives:
·Understand the development of mobile communications, and Long
Term Evolution (LTE position and net!or" architecture#
·Understand the protocol architecture and basic technologies of E$
UT%&'#
·Understand "e LTE technologies#
8/18/2019 4.LTE Overview 69
2/62
Contents
1 Overview........................................................................................................................................................1
)#) *ac"ground##########################################################################################################################################)
)#)#) +obile Communications Evolution###########################################################################################)
)#)# Comparison &mong -C.+&, T.$/C.+&, and C.+&000##############################################
)#)#1 -C.+& Evolution##################################################################################################################
)#)#2 T.$/C.+& Evolution#############################################################################################################1
)#)#3 C.+&00 Evolution################################################################################################################2
)# LTE Overvie! and /tandards .evelopment########################################################################################3
2 LTE Indexes and Requirements...................................................................................................................5
#) 4re5uenc *and .ivision#####################################################################################################################6
# 7ea" .ata %ate#####################################################################################################################################8
#1 Control 7lane .ela#############################################################################################################################8
#2 User 7lane .ela##################################################################################################################################8
#3 User Throughput###################################################################################################################################9
#6 /pectrum Efficienc#############################################################################################################################9
#8 +obilit################################################################################################################################################9
#9 Coverage##############################################################################################################################################
# /pectrum 4le;ibilit#############################################################################################################################
#)0 Coe;istence and and O7E>##########################################################################################################)0
3 LTE Architecture.........................................................................................................................................11
1#) /stem &rchitecture############################################################################################################################))
1# %adio 7rotocol &rchitecture###############################################################################################################)3
8/18/2019 4.LTE Overview 69
3/62
1##) Control 7lane 7rotocol &rchitecture#######################################################################################)3
1## User 7lane 7rotocol &rchitecture############################################################################################)6
1#1 /)
8/18/2019 4.LTE Overview 69
4/62
3#1# 7.U /tructure#########################################################################################################################1
" RR#..............................................................................................................................................................3$
6#) %%C 4unctions###################################################################################################################################1
6# %%C /tate##########################################################################################################################################20
6#1 '&/ /tate and the %elationship -ith the %%C state#########################################################################2)
6#2 %%C 7rocedure##################################################################################################################################2
6#2#) /stem
8/18/2019 4.LTE Overview 69
5/62
8/18/2019 4.LTE Overview 69
6/62
LTE Overvie!
.evelopment and evolution of !ireless communication technologies
1.1.2 Comparison mong !C"M# T"$%C"M# and C"M2&&&
Comparison among -C.+&, T.$/C.+&, and C.+&000
/tandard -C.+& C.+&000 T.$/C.+&
8/18/2019 4.LTE Overview 69
7/62
Chapter 8 Core LTE Technologies
-C.+& technolog roadmap
1.1.( T"$%C"M Evolution
DTE !ireless net!or" e5uipment supports smooth evolution of recent T. evolution
soft!are#
T. evolution can be divided into t!o stages: standard stage of C.+& technologies and
that of O4.+& technologies#
The standard stage of C.+& technologies can smoothl evolve to @/7& !ith
spectrum efficienc close to that of LTE#
3
8/18/2019 4.LTE Overview 69
8/62
LTE Overvie!
Basic version
Short-term evolution version
Mid-term evolution version
Long-term evolution version (4G)
Phase I Phase II Phase III
C"M standard O)"M standard
'*++ ,-(/oice0"ata
re3uenc4 point
'*++ ,-506078%+08%+9
MBM%0Multi$Carrier
'*++ LTEO)"MM:MO
:MT$dv
T.$/C.+& evolution
1.1.5 C"M2&& Evolution
C.+& One is a collection of all
8/18/2019 4.LTE Overview 69
9/62
Chapter 8 Core LTE Technologies
1.2 LTE Overview and %tandards "evelopment
1=77 !or"ing groups started LTE standardi?ation in .ecember 002# LTE focuses on
the enhancement of UT%&' and UT%
The establishment of 1=77 standards can be divided into four stages including
re5uirements proposal, architecture establishment, detailed specifications, and testing
and verification#
1=77 !or"s in !or"group mode and %&')BB1B2B3 !or"groups are directl related to
LTE#
5
8/18/2019 4.LTE Overview 69
10/62
LTE Overvie!
Organi?ation and establishment stages of 1=77 standards
6
8/18/2019 4.LTE Overview 69
11/62
2 LTE :nde;es and -e3uirements
Knowledge points
/pectrum division
LTE sstem re5uirements
Others
7hsical channels and mapping relationship
4igure 6 sho!s the LTE inde;es and re5uirements prescribed b 1=77#
LTE inde;es and re5uirements
5
8/18/2019 4.LTE Overview 69
12/62
2.1 )re3uenc4 Band "ivision
Table lists the E$UT%& fre5uenc bands#
E$UT%& fre5uenc bands
E$UT%&
Operating
*and
Uplin" (UL operating band */ receive
UE transmit
.o!nlin" (.L operating band */
transmit UE receive
.uple;
+ode
4ULFlo! G 4ULFhigh 4.LFlo! G 4.LFhigh
) )0 +@? G )90 +@? ))0 +@? G )80 +@? 4..
)930 +@? G ))0 +@? )10 +@? G )0 +@? 4..
1 )8)0 +@? G )893 +@? )903 +@? G )990 +@? 4..
2 )8)0 +@? G )833 +@? ))0 +@? G )33 +@? 4..
3 92 +@? G 92 +@? 96 +@? G 92+@? 4..
6 910 +@? G 920 +@? 983 +@? G 993 +@? 4..
8 300 +@? G 380 +@? 60 +@? G 60 +@? 4..
9 990 +@? G )3 +@? 3 +@? G 60 +@? 4..
)82# +@? G )892# +@? )922# +@? G )98# +@? 4..
)0 )8)0 +@? G )880 +@? ))0 +@? G )80 +@? 4..
)) )28# +@? G )23# +@? )283# +@? G )300# +@? 4..
) 69 +@? G 8)6 +@? 89 +@? G 826 +@? 4..)1 888 +@? G 898 +@? 826 +@? G 836 +@? 4..
)2 899 +@? G 89 +@? 839 +@? G 869 +@? 4..
H
)8 802 +@? G 8)6 +@? 812 +@? G 826 +@? 4..
###
11 )00 +@? G )0 +@? )00 +@? G )0 +@? T..
12 0)0 +@? G 03 +@? 0)0 +@? G 03 +@? T..
13 )930 +@? G ))0 +@? )930 +@? G ))0 +@? T..
16 )10 +@? G )0 +@? )10 +@? G )0 +@? T..
18 ))0 +@? G )10 +@? ))0 +@? G )10 +@? T..
19 380 +@? G 60 +@? 380 +@? G 60 +@? T..
1 )990 +@? G )0 +@? )990 +@? G )0 +@? T..
20 100 +@? G 200 +@? 100 +@? G 200 +@? T..
2.2 +eak "ata -ate
The instantaneous do!nlin" pea" rate reaches )00 +bitBs (3 bitBsB@? at 0 +@?
6
8/18/2019 4.LTE Overview 69
13/62
Chapter 8 Core LTE Technologies
do!nlin" spectrum band (t!o transmit antennas on the net!or" side and t!o receive
antennas on the UE side#
The instantaneous uplin" pea" rate reaches 30 +bitBs (#3 bitBsB@? at 0 +@? uplin"
spectrum band (one receive antenna on the UE side#
-idebands, + interval#
&dditionall, if the control plane operates at 3 +@? spectrum band, each cell is e;pectedto support 00 activated users#
8/18/2019 4.LTE Overview 69
14/62
LTE Overvie!
)# The user throughput per +@? at the 3J Cumulative .istribution 4unction (C.4
must reach t!o to three times the throughput of %6 @/.7
# The average user throughput per +@? must reach three to four times the
throughput of %6 @/.7
%6 @/.7& uses one transmitter one receiver ()T)% !hile LTE uses t!o transmitterBt!o
receiver (T%#
Uplin":
)# The user throughput per +@? at the 3J C.4 must reach t!o to three times the
throughput of %6 @/U7
# The user throughput per +@? must reach t!o to three times the throughput of %6
@/U7
%6 @/U7& uses )T%, and so does LTE#
2.6 %pectrum Eicienc4
.o!nlin": On a net!or" !ith effective load, the target LTE spectrum efficienc(measured b the bit 5uantit per site, per @?, and per second is three to four times
more efficient than %6 @/U7 %6 @/.7& uses )T)% !hile LTE uses T%#
Uplin": On a net!or" !ith effective load, the target LTE spectrum efficienc (measured
b the bit 5uantit per site, per @?, and per second is t!o to three times more efficient
than %6 @/U7 %6 @/U7& uses )T%, and so does LTE#
2.7 Mobilit4
E$UT%&' can provide optimum net!or" performance for mobile users at the speed of
0–)3 "mBh, high performance services at the speed of )3–)0 "mBh, and cell net!or"
services at the speed of )0–130 "mBh (the speed even reaches 300 "mBh at specified
bands#
oice services and other realtime services provided in the %6 C/ domain are supported
b 7/ domain on the E$UT%&' and all these services can reach or e;ceed the 5ualit of
UT%&' services# The interrupt time caused b handovers !ithin the E$UT%& sstem
8
8/18/2019 4.LTE Overview 69
15/62
Chapter 8 Core LTE Technologies
must be shorter than or e5ual to the handover time of the =E%&' C/ domain#
Coverage
The E$UT%& sstem must fle;ibl support all coverage scenarios on the basis of reusing
the current UT%&' sites and fre5uencies to meet the preceding performance inde;es
such as the user throughput, spectrum efficienc, and mobilit#
The performance re5uirements of the E$UT%& sstem !ithin different coverage scope
are listed as follo!s:
)# Coverage radius !ithin 3 "m: The preceding performance inde;es such as the user
throughput, spectrum efficienc, and mobilit must be full satisfied#
# Coverage radius !ithin 10 "m: The throughput and spectrum efficienc areallo!ed to slightl drop but !ithin an acceptable range, and the mobilit inde;
must be full satisfied#
1# +a;imum coverage radius: )00 "m#
2.? %pectrum )le;ibilit4
On the one hand, the spectrum fle;ibilit allo!s deploment of E$UT%& at varied bands
including )#2 +@?, 1 +@?, 3 +@?, )0 +@?, )3 +@?, and 0 +@?# The E$UT%&
supports paired and unpaired spectrums#
On the other hand, the spectrum fle;ibilit allo!s consolidation of spectrum bands#
2.1& Coe;istence and :nteroperabilit4 wit= E;isting '*++ %4stems
8/18/2019 4.LTE Overview 69
16/62
LTE Overvie!
)# E$UT%&' and UT%&'B=E%&' multi$mode terminals support
UT%&'B=E%&' measurement and handover bet!een E$UT%&' sstems and
UT%&'B=E%&' sstems#
# The E$UT%&' sstem supports inter$sstem measurement#
1# The handover interrupt time bet!een %$UT%&' and UT%&' must be shorter
than 100 ms for realtime services#
2# The handover interrupt time bet!een E$UT%&' and UT%&' must be shorter
than 300 ms for non$realtime services#
3# The handover interrupt time bet!een E$UT%&' and =E%&' must be shorter
than 100 ms for realtime services#
6# The handover interrupt time bet!een E$UT%&' and =E%&' must be shorter
than 300 ms for non$realtime services#
8# 7aging information of onl one of the =E%&', UT%&, or E$UT%& sstems
needs to be monitored for multi$mode terminals in non$active state (similar to %6
8/18/2019 4.LTE Overview 69
17/62
' LTE rc=itecture
Knowledge points
%adio protocol structure
/) interface
> interface
'.1 %4stem rc=itecture
LTE adopts an O4.+$based air interface technolog !hich is different from those of
= and 1=# LTE adopts a flat net!or" architecture !ithin !hich E$UT%&' contains
onl e'ode*s instead of %'C, so as to optimi?e the traditional 1= net!or" architecture#
LTE supports functions of 7.C7B%LCB+&CBphsical laer protocols on the E$UT%&
user plane and functions of the %%C protocol on the control plane# 4igure 9 sho!s the E$
UT%&' sstem architecture#
E$UT%&' architecture
8/18/2019 4.LTE Overview 69
18/62
e'ode*s are connected over an ; interface and ever e'ode* is connected to the
Evolved 7ac"et Core (E7C net!or" over an /) interface# The user plane of /)
interfaces terminates on the /erving$=ate!a (/$=- and the control plane of /)
interfaces terminates on the +obile +anagement Entit (++E# The other end of the
control plane and user plane terminates on the e'ode*# 4unctions of all 'Es in the
preceding figure are listed as follo!s:
e'ode*
*esides the original e'ode* functions, e'ode* of LTE underta"es most of original
%'C functions such as phsical laer, +&C (including @&%A, %LC laer (including
&%A functions, 7.C7, %%C, scheduling, radio access control, access mobilit
management, and radio resource management among different cells#
LTE e'ode*s have the follo!ing functions:
− +anage radio resources: %adio bearer control, radio access control, connection
mobilit control, and dnamic resource assignment of uplin" and do!nlin"
(scheduling#
− Compress
8/18/2019 4.LTE Overview 69
19/62
Chapter 8 Core LTE Technologies
The function of the ++E is separated from that of the gate!a# The control planeBuser
plane separated structure facilitates net!or" deploment, single technolog evolution,
and fle;ible capacit e;pansion#
− '&/ signaling
− '&/ signaling securit
− &/ securit control
− +obile signaling among 1=77 radio net!or"s
− The reachabilit of an UE in the idle state (including the control and
implementation of paging signal re$transmission
− Trac"ing area list management
− 7$=- or /$=- selection
− ++E selection at the time of handover
− /=/' selection at handover to = or 1=77 net!or"
− %oaming
− &uthentication
− *earer management, including dedicated bearer establishment
− ET-/ signal transmission
/$=-
&s the anchor point at local e'ode* handover, /$=- implements the follo!ing
functions: data transfer bet!een the e'ode* and the public data gate!a, do!nlin"
pac"et buffer, and user$based billing#
− Local mobile anchor points at e'ode* handover
− +obile anchor points among 1=77 sstems#
3
8/18/2019 4.LTE Overview 69
20/62
LTE Overvie!
− .o!nlin" pac"et buffering and initiali?ation of net!or"$triggered service re5uest
procedure in the E$UT%&' idle mode
− La!ful interception
− 7ac"et routing and for!arding
− Transport$laer pac"et mar"ing (uplin"Bdo!nlin"
− &ccounting on user and AC< granularit for inter$operator charging#
− Uplin"Bdo!nlin" charging per UE, 7.', or AC<
7.' gate!a (7$=-
&s the designated anchor point of the data bearer, the 7ublic .ata 'et!or" =ate!a (7$
=- has the follo!ing functions: 7ac"et for!arding, pac"et resolving, la!ful
interception, service$based billing, Ao/ control, and interconnection !ith non$1=77
net!or"s#
− 7er$user pac"et filtering (for e;ample, utili?e deep pac"et inspection
− La!ful interception
− interface in the ne! LTE
architecture#
4igure 9 sho!s the functional split bet!een E$UT%&' and E7C# ello! bo;es depict
the logical nodes, !hite bo;es the functional entities of the control plane, and blue bo;es
the radio protocol laers#
4
8/18/2019 4.LTE Overview 69
21/62
Chapter 8 Core LTE Technologies
4unctional split bet!een E$UT%&' and E7C
'.2 -adio +rotocol rc=itecture
'.2.1 Control +lane +rotocol rc=itecture
4igure )0 sho!s the control plane protocol architecture#
Control plane protocol stac"
5
8/18/2019 4.LTE Overview 69
22/62
LTE Overvie!
The 7.C7 terminates at e'ode* and implements functions such as control plane
encrption and integrit protection#
The %LC and +&C terminate at e'ode* on the net!or" side and implement identical
functions of the user plane and control plane#
The %%C terminates at e'ode* and implements such functions as broadcast, paging,
%%C connection management, %* control, mobilit, and UE measurement reporting and
control#
The '&/ terminates at ++E and implements such functions as E7/ bearer
management, authentication, idle$mode E7/ Connection +anagement (EC+, idle$mode
EC+ paging, and securit control#
'.2.2
8/18/2019 4.LTE Overview 69
23/62
Chapter 8 Core LTE Technologies
'.'.1 %1 :nterace
The /) interface is defined as the interface bet!een the E$UT%&' and E7C# The /)interface contains t!o parts: the control plane /)$++E interface and user plane /)$U
interface# The /)$++E interface is defined as the interface bet!een the e'ode* and
++EM the /)$UE interface is defined as the interface bet!een the e'ode* and /$=-#
4igure ) and 4igure )1 respectivel sho! the protocol stac" architecture of the /)$
++E interface and /)$U interface#
/) interface control plane (e'ode*$++E
/) interface user plane (e'ode*–/$=-
7
8/18/2019 4.LTE Overview 69
24/62
LTE Overvie!
The /) interface has the follo!ing ac"no!ledged functions:
E$%&* service management
− Establishment, modification, and release
UE mobilit in the EC+$CO''ECTE. state
− @andover !ithin the LTE sstem
− @andover bet!een the LTE sstem and the 1=77 sstem
/) paging
'&/ signaling transmission
/) interface management
− Error indication
− %eset
'et!or" sharing
%oaming and area restriction
'&/ node selection
8/18/2019 4.LTE Overview 69
25/62
Chapter 8 Core LTE Technologies
%&' information management
The /) interface has the follo!ing ac"no!ledged signaling procedures:
E$%&* signaling procedure
− E$%&* establishment
− E$%&* modification
− ++E$initiated E$%&* release
− e'ode*$initiated E$%&* release
@andover signaling procedure
− @andover preparation
− %esource assignment
− @andover termination
− @andover cancellation
7aging
'&/ transmission procedure
− .irect uplin" transmission (initial UE message
− .irect uplin" transmission (uplin" '&/ transmission
− .irect do!nlin" transmission (do!nlin" '&/ transmission
Error indication procedure
− e'ode*$initiated error indication
− ++E$initiated error indication
9
8/18/2019 4.LTE Overview 69
26/62
LTE Overvie!
%eset
− e'ode*$initiated reset
− ++E$initiated reset
8/18/2019 4.LTE Overview 69
27/62
Chapter 8 Core LTE Technologies
$
U adopt the same user plane protocol to reduce protocol processing at e'ode* data
for!ard#
'.'.2 @2 :nterace
The > interface is defined as the interface bet!een e'ode*s# The > interface contains
t!o parts: the >$C7 and >$U, !here the >$C7 is the control plane interface bet!een
e'ode*s and the >$U is the user plane interface bet!een e'ode*s# 4igure )3 and
4igure )6 respectivel sho! the protocol stac" architecture of the >$C7 interface and
>$U interface#
8/18/2019 4.LTE Overview 69
28/62
LTE Overvie!
> interface control plane
> interface user plane
The >$C7 has the follo!ing functions:
UE mobilit in the EC+$CO''ECTE. state !ithin the LTE sstem
− Conte;t transfer from the source e'ode* to the target e'ode*
− User plane channel control bet!een the source e'ode* and the target e'ode*
− @andover cancellation
8/18/2019 4.LTE Overview 69
29/62
Chapter 8 Core LTE Technologies
Uplin" load management
=eneral > interface management and error processing
− Error indication
The >$C7 interface has the follo!ing ac"no!ledged signaling procedures:
@andover preparation
@andover cancellation
UE conte;t release
Error indication
Load management
The management of load among cells is implemented over the > interface#
4igure )8 sho!s that the LO&. interface LO&.
8/18/2019 4.LTE Overview 69
30/62
( +=4sical La4er
(.1 )rame %tructure
The LTE sstem supports the follo!ing t!o radio frame structures:
/tructure ): &pplicable to the 4.. mode#
/tructure : &pplicable to the T.. mode#
4igure )9 sho!s the frame structure )# Ever )0 ms radio frame is divided into ten sub$
frames of fi;ed length# Each sub$frame contains t!o time slots each of !hich is 0#3 ms
long#
4rame structure )
4or 4.., at ever )0 ms, ten sub$frames can be used for do!nlin" transmission and
another ten sub$frames can be used for uplin" transmission# The uplin" transmission and
do!nlin" transmission are separated on the fre5uenc domain#
(.2 +=4sical -esources
The minimum resource unit for uplin"Bdo!nlin" transmission in the LTE sstem is called
the %esource Element (%E#
&t the time of data transmission, the LTE sstem consolidates uplin" and do!nlin" time$
fre5uenc domain phsical resources into %esource *loc"s (%*s for scheduling and
allocation#
8/18/2019 4.LTE Overview 69
31/62
/everal %Es constitute an %*# There are ) consecutive sub$carriers on the fre5uenc
domain and seven consecutive O4.+ smbols (si; mar"s !ith the E;tended C7# That
is, the fre5uenc domain !idth is )90 "@? and the time length is 0#3 ms#
4igure ) and 4igure 0 respectivel sho! the phsical resource structures of do!nlin"
and uplin" slots#
7hsical resource structure of do!nlin" slot
8/18/2019 4.LTE Overview 69
32/62
Chapter 8 Core LTE Technologies
7hsical resource structure of uplin" slot
(.' +=4sical C=annels
The do!nlin" phsical channels contain the follo!ing channels:
1 7hsical *roadcast Channel (7*C@
− The coded *C@ transmission bloc" maps to four sub$frames !ithin an 20 ms
interval#
− The 20 ms timing is obtained b blind tests, namel, no specified signaling
3
8/18/2019 4.LTE Overview 69
33/62
LTE Overvie!
indicates the 20 ms timing#
− -ith e;cellent$enough channels, ever sub$frame that the 7*C@ located canseparatel decode signals#
2 7hsical Control 4ormat
8/18/2019 4.LTE Overview 69
34/62
Chapter 8 Core LTE Technologies
# 7hsical Uplin" /haring Channel (7U/C@
− Carr the UL$/C@ information#
$ 7hsical %andom &ccess Channel (7%&C@
− Carr the random access preamble#
(.( Transport C=annels
The do!nlin" transport channels contain the follo!ing channels:
1% *roadcast Channel (*C@
− 4i;ed predefined transport format
− *roadcast in the entire coverage area of the cell
11 .o!nlin" /haring Channel (.L$/C@
− /upport @&%A#
− period to the
5
8/18/2019 4.LTE Overview 69
35/62
LTE Overvie!
UE#
− *roadcast in the entire coverage area of the cell
− +ap to phsical resources !hich can be used dnamicall also for traffic or other
control channels#
13 +ulticast Channel (+C@
− *roadcast in the entire coverage area of the cell
− /upport +ulticastB*roadcast over /ingle 4re5uenc 'et!or" (+*/4' combingof +*+/ transmission on multiple cells#
− /upport semi$static resource allocation#
The uplin" transport channels contain the follo!ing channels:
14 Uplin" /haring Channel (UL$/C@
−
/upport beamforming#
−
8/18/2019 4.LTE Overview 69
36/62
Chapter 8 Core LTE Technologies
(.5 Mapping Between Transport C=annels and +=4sical C=annels
4igure ) and 4igure respectivel sho! the mapping relationships bet!een
do!nlin"Buplin" transport channels and do!nlin"Buplin" phsical channels#
+apping bet!een do!nlin" transport channels and do!nlin" phsical channels
+apping bet!een uplin" transport channels and uplin" phsical channels
(.6 +=4sical %ignals
7hsical signals correspond to several phsical laer %Es, but do not carr an
information that comes from higher laers#
The do!nlin" phsical signals include the reference signal and the snchroni?ation
signal#
%eference signal
The do!nlin" reference signals include the follo!ing three tpes of reference signals:
7
8/18/2019 4.LTE Overview 69
37/62
LTE Overvie!
− Cell$specific reference signals, associated !ith non$+*/4' transmission
− +*/4' reference signals, associated !ith +*/4' transmission
− UE$specific reference signals
/nchroni?ation signals
The snchroni?ation signals include the follo!ing t!o tpes of signals:
− 7rimar snchroni?ation signal
− /econdar snchroni?ation signal
4or 4.., the primar snchroni?ation signal maps to the last O4.+ smbol of the time
slot 0 and time slot )0# The secondar snchroni?ation signal maps to the second last
O4.+ smbol of the time slot 0 and time slot )0#
The uplin" phsical signals include the reference signals#
%eference signals
The uplin" reference signals include the follo!ing t!o tpes of signals:
− .emodulation reference signals, associated !ith 7U/C@ or 7UCC@ transmission
− /ounding reference signals, not associated !ith 7U/C@ or 7UCC@ transmission
The demodulation reference signals and the sounding reference signals use the same base
se5uence set#
(.7 +=4sical La4er Model
The follo!ing figures sho! the phsical laer models of various tpes of channels# 'ode
*s in all of the follo!ing figures are called e'ode*s or e'ode* in LTE#
8
8/18/2019 4.LTE Overview 69
38/62
8/18/2019 4.LTE Overview 69
39/62
8/18/2019 4.LTE Overview 69
40/62
Chapter 8 Core LTE Technologies
7hsical laer model for UL$/C@ transmission
(.> +=4sical La4er +rocedures
(.>.1 %4nc=roniation +rocedures
Cell search
Cell search is the procedure b !hich a UE ac5uires time and fre5uenc snchroni?ation
!ith a cell and detects that cells phsical laer cell
8/18/2019 4.LTE Overview 69
41/62
LTE Overvie!
Uplin" po!er control procedure controls the transmit po!er of different uplin" phsical
channels#
.o!nlin" po!er allocation
e'ode* determines the do!nlin" transmit energ per resource element#
(.>.' -andom ccess +rocedures
7rior to initiation of the non$snchroni?ed phsical random access procedure, phsical
laer shall receive the follo!ing information from the higher laers:
)# %andom access channel parameters (7%&C@ configuration, fre5uenc position,and preamble format#
# 7arameters for determining the root se5uences and their cclic shifts in the
preamble se5uence set for the cell (inde; to root se5uence table, cclic shift
('cs, and set tpe (normal or high$speed set#
4rom the phsical laer perspective, the phsical random access procedure encompasses
the transmission of random access preamble and random access response# The remaining
messages are scheduled for transmission b the higher laer on the shared data channel
and are not considered part of the L) random access procedure#
The follo!ing steps are re5uired for the phsical random access procedure:
)# 7hsical laer procedure is triggered upon re5uest of a preamble transmission b
higher laers#
# & preamble inde;, preamble transmission po!er
(7%E&+*LEFT%&'/+
8/18/2019 4.LTE Overview 69
42/62
Chapter 8 Core LTE Technologies
3# & single preamble transmission then occurs using the selected preamble se5uence
!ith transmission po!er 7%E&+*LEFT%&'/+
8/18/2019 4.LTE Overview 69
43/62
5 La4er 2
Laer consists of three sublaers 7.C7, %LC, and +&C# 4igure 9 and 4igure
respectivel sho! Laer do!nlin" and uplin" structures#
Laer do!nlin" structure
3
8/18/2019 4.LTE Overview 69
44/62
Laer uplin" structure
The connection points among sublaers are "no!n as the /ervice &ccess 7oints (/&7#
The service provided b 7.C7 is referred to as the radio bearer# The 7.C7 provides the
%obust @eader Compression (%O@C and securit protection# The /&7 bet!een
phsical laer and +&C laer provides transport channels and that bet!een +&C laer
and %LC laer provides logical channels#
The +&C laer provides multiple;ing and mapping of logical channels (radio bearer to
transport channels (transport bloc"#
Onl one transport bloc" is generated at each TT< () ms in the uplin" or do!nlin" in thecase of non$+
8/18/2019 4.LTE Overview 69
45/62
Chapter 8 Core LTE Technologies
· +apping bet!een logical channels and transport channels#
· +&C /ervice .ata Unit (/.U multiple;ingBdemultiple;ing#
· /cheduling information report#
· Error correction through @&%A
· Logical channel prioriti?ation of the same UE#
· UE prioriti?ation through dnamic scheduling#
· /election of transmission formats#
· 7adding#
5.1.2 Logical C=annels
+&C provides different tpes of data transmission services# The tpe of each logical
channel is defined based on the tpe of transmitted data#
Logical channels are categori?ed into:
· Control channels: used to transfer data on the control plane#
· Traffic channels: used to transfer data on the user plane#
Control channels include:
· *roadcast Control Channel (*CC@#
The *CC@ is a do!nlin" channel used to broadcast sstem control messages#
· 7aging Control Channel (7CC@#
The 7CC@ is a do!nlin" channel used to transfer paging messages and sstem
information change notifications# The 7CC@ is used to page a UE !hen the UE
cell location is un"no!n to the net!or"#
· Common Control Channel (CCC@#
34
8/18/2019 4.LTE Overview 69
46/62
LTE Overvie!
The CCC@ is used to transfer control messages bet!een UEs and net!or" !hen
there is no %%C connection bet!een them#
· +ulticast Control Channel (+CC@#
& point$to$multipoint do!nlin" channel used for transmitting +*+/ control
information from the net!or" to the UE, for one or several +TC@s# This channel
is onl used to UEs that receive +*+/#
· .edicated Control Channel (.CC@#
& point$to$point bi$directional channel that transmits dedicated controlinformation bet!een a UE and the net!or"# This channel is used b UEs having
an %%C connection#
·Traffic channels include:
· .edicated Traffic Channel (.TC@#
The .TC@ is a point$to$point channel, dedicated to one UE, for the transfer of
user information#
· +ulticast Traffic Channel (+TC@#
& point$to$multipoint do!nlin" channel for transmitting traffic data from the
net!or" to the UE# This channel is onl used to UEs that receive +*+/#
5.1.' Mapping Between Logical C=annels and Transport C=annels
4igure 10 and 4igure 1) respectivel sho! the mapping bet!een do!nlin" and uplin"
logical channels and transport channels#
35
8/18/2019 4.LTE Overview 69
47/62
Chapter 8 Core LTE Technologies
+apping bet!een do!nlin" logical channels and transport channels
+apping bet!een uplin" logical channels and transport channels
5.2 -LC %ubla4er
5.2.1 -LC )unctions
The %LC sublaer provides the follo!ing functions:
· Transfer of upper laer 7.Us#
· Error Correction through &%A (onl for &+ data transfer#
· Concatenation, segmentation and reassembl of %LC /.Us (onl for U+ and
&+ data transfer#
· %e$segmentation of %LC data 7.Us (onl for &+ data transfer#
36
8/18/2019 4.LTE Overview 69
48/62
LTE Overvie!
·
8/18/2019 4.LTE Overview 69
49/62
8/18/2019 4.LTE Overview 69
50/62
6 --C
6.1 --C )unctions
+ain 4unctions of %%C include:
· *roadcast of sstem information related to the '&/s
· *roadcast of sstem information related to the &/s
· 7aging
· Establishment, retention, and release of %%C connection bet!een UEs and E$
UT%&'s, including:
− &llocation of temporar identifiers bet!een UEs and E$UT%&'s
− Configuration of the /ignaling %adio *earers (/%*s for %%C connection
♦ Lo! priorit and high priorit /%*s
· /ecurit management including "e management
· Establishment, configuration, retention, and release point$to$point %*s
· +obilit management, including:
− +easurement report and reporting control of the mobile UEs bet!een cells
and bet!een %&Ts#
− @andover
− UE cell selection and reselectionM cell selection and reselection control
− Conte;t for!arding during handover
38
8/18/2019 4.LTE Overview 69
51/62
· +*+/ notification
· Establishment, configuration, retention, and release of %*s for the +*+/
· Ao/ management
· UE measurement report and reporting control
· '&/ direct transfer
6.2 --C %tate
%%C state includes %%CF
8/18/2019 4.LTE Overview 69
52/62
Chapter 8 Core LTE Technologies
− The net!or" can transmit and receive data toBfrom the UEs#
− 'et!or" controlled mobilit (handover#
− 'eighbor cell measurements#
− The 7.C7B%LCB+&C features of the %%CFCO''ECTE.
♦ The UE can transmit and receive data toBfrom the net!or"s#
♦ The UE intercepts controlled signaling channels related to the shared data
channels to vie! that !hether the UE is allocated an data on the shared
data channel#
♦ The UE also reports channel 5ualit information and feeds bac"
information to e'ode*#
♦ The .%> ccle can be conformed according to the UE mobilit level to
save UE po!er and enhance resource efficienc# This function is
controlled b e'ode*#
6.' % %tate and t=e -elations=ip !it= t=e --C state
The '&/ state model can be described b the t!o$dimensional state model of the E7/
+obilit +anagement state (E++ and the E7/ Connection +anagement state#
· E++ state:
− E++$.E%E=
8/18/2019 4.LTE Overview 69
53/62
LTE Overvie!
'ote: The E++ state and the EC+ state are mutuall independent#
The relationship bet!een the '&/ state and the %%C state is as follo!s:
· E++$.E%E=
8/18/2019 4.LTE Overview 69
54/62
Chapter 8 Core LTE Technologies
information bloc"s#
· /stem
8/18/2019 4.LTE Overview 69
55/62
LTE Overvie!
· %%C connection establishment
·
8/18/2019 4.LTE Overview 69
56/62
7 Core LTE Tec=nologies
7.1 "uple; Mode
8/18/2019 4.LTE Overview 69
57/62
+ultiple;ing scheme in LTE uplin" sstems
7.' Multi$antenna Tec=nologies
.o!nlin" multi$antenna transmission:
+ulti$antenna transmission supports t!o or four antennas# The ma;imum number of
code !ords is and irrelevant of the number of antennas, but there is a fi;ed mapping
relationship bet!een core !ords and laers# 4igure 13 sho!s the general relationship
among code !ords, laers, and antenna ports#
7hsical channel processing
+ulti$antenna technologies include the /.+ and transmit diversit# The /.+ supports
/U$+
8/18/2019 4.LTE Overview 69
58/62
Chapter 8 Core LTE Technologies
transmitting on a single antenna, is supported#
Closed loop tpe adaptive antenna selection transmit diversit shall be supported for
4.. (optional in UE#
7.( Link daptation
.o!nlin" adaptation:
%efer to the adaptive modulation and coding (&+C that is applied !ith three
modulation schemes (A7/N, )6A&+, and 62A&+ and variable code rates#
Uplin" adaptation:
8/18/2019 4.LTE Overview 69
59/62
LTE Overvie!
·
8/18/2019 4.LTE Overview 69
60/62
Chapter 8 Core LTE Technologies
7.5.' 8-A0-A :nteractions
8/18/2019 4.LTE Overview 69
61/62
> bbreviations
&bbreviation 4ull 'ame
1=77 1rd =eneration 7artnership 7roject
*7/N *inar 7hase /hift Neing
C&7E> Capital E;penditure
.4T .iscrete 4ourier Transform
.%> .iscontinuous %eception
E$+*+/ Evolved +ultimedia *roadcast and +ulticast /ervice
e'ode* Evolution 'ode *
E1= evolved 1=
E7C Evolved 7ac"et Core
E$UT%& Evolved Universal Terrestrial %adio &ccess
@C% @igh Chip %ate
@e'* @ome e'ode*
8/18/2019 4.LTE Overview 69
62/62
? -eerences
/' 'ame
)3#) 4easibilit stud for evolved Universal Terrestrial %adio &ccess (UT%& and
Universal Terrestrial %adio &ccess 'et!or" (UT%&'
3#)1 %e5uirements for Evolved UT%& (E$UT%& and Evolved UT%&' (E$UT%&'
116#100 Evolved Universal Terrestrial %adio &ccess (E$UT%& and Evolved Universal
Terrestrial %adio &ccess 'et!or" (E$UT%&', Overall description
2 3#9)2 7hsical laer aspects for evolved Universal Terrestrial %adio &ccess (UT%&
3 16#)) 7hsical Channels and +odulation
6 16#) +ultiple;ing and channel coding
8 16#)1 7hsical laer procedures
9 16#)2 7hsical laer G +easurements
16#10 /ervices provided b the phsical laer
)0 16#11) %adio %esource Control (%%C
)) 16#)02 *ase /tation (*/ radio transmission and reception
) 16#1) +edium &ccess Control (+&C protocol specification
)1
1#20) =eneral 7ac"et %adio /ervice (=7%/ enhancements for Evolved Universal
Terrestrial %adio &ccess 'et!or" (E$UT%&' access
)2 1#01 7olic and charging control architecture