gb bt04 e1 0 gsm advanced technology-32
TRANSCRIPT
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GB_BT04_E1_0 GSM Advanced Technology
Course Objectves!
Understand HR services and implementation methods
Understand principles of ZTE ultra-distance coverage
technology
Understand concepts, features and specifications of
EDGE technology
Grasp satellite Ais transmission configurations
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Contents
1 "# Servces$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$1
!"! #asic $oncepts""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""!
!"% HR &rame 'tructure""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""!
!"( HR 'ervice )mplementation"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""(
!"* HR 'ervice Upgrade"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""*
!"+ HR $hannel Allocation 'trategies""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""+
!" HR 'ervice Applications"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
% <ra'(stance Coverage Technology$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$)
%"! Technological #acground""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""".
%"% /rotocol Restrictions""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""".
%"%"! Radio )nterface Restrictions"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""".
%"( #reathrough 0ethods"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""!%
%"("! #reathrough 0ethod !"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""!%
%"("% #reathrough 0ethod %"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""!(
* E(GE Technology$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$1+
("! Definitions""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""!1
("% &eatures"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""!1
("( 'pecifications""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""!2
("* 3ey Technologies""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""!.
("*"! EDGE 0odulation 0odes"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""!.
("*"% EDGE Radio #loc 'tructure""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""%4
("*"( $hannel $oding"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""%4
4 Satellte Abs Technology$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$%*
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*"! 5vervie6"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""%(
*"% 'atellite Transmission &eatures and 'olutions"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""%(
*"( Z7G!4-#'' 'atellite Ais /rinciples""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""%*
*"* Z7G!4-#'' 'atellite Ais /hysical $onfigurations and Re8uirements"""""""""""""""""""""""""""""""""""""%*
*"+ Z7G!4-#'' 'atellite Ais $onfigurations""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""%+
*"+"! Timeslot $onfigurations during $ommissioning 9D)/ '6itch 'etting:"""""""""""""""""""""""""""""%+
*"+"% /recautions of Radio /arameter 'ettings""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""%1
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1 HR Services
1.1 Basic Concepts
As defined in G'0 specifications, the G'0 physical layer is comination of &D0A
and TD0A" G'0 fre8uency ands are divided into many %44-H; channels according
to fre8uency division principles" )n G'0 specifications, each channel has an Asolute
Radio &re8uency $hannel
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is enhanced and the net6or congestion rate is reduced" Ho6ever, it also rings aout
the negative effect that the channel coding rate decreases and voice 8uality degrades"
&igure !"% -! sho6s the relationship et6een the &R channel=s frame structure and the
HR channel=s frame structure"
&igure !"%-! Relationship et6een &R-coded Data &rame and HR-coded Data &rame
ZTE e8uipments support oth static HR service and dynamic HR service"
'tatic HR service
'tatic HR service means that the system HR channels are decided in net6or
planning, and the static configuration is made on the system 50$R e8uipments"
During the system running, the HR channel occupies fi?ed carrier and timeslots,and each timeslot on the carrier maintains its status as HR or &R that is set 6hen
eing allocated, and the status can not e changed" &ine ad@ustment can e made
to the static configuration in later net6or optimi;ation"
Dynamic HR service
Dynamic HR service means that only &R service is provided during the system=s
initial running, and the ratio of commissioned HR channels depends on the traffic
change during system running"
hen the traffic increases, the reserved dynamic HR au?iliary timeslots of
Ais interface are used to start the conversion from idle &R channels to HR
channels" )n this 6ay, HR channels are used to increase the system traffic
capacity and reduce the congestion rate"
hen the traffic decreases, the conversion from idle HR channels to &R
channels is started, to guarantee the system voice 8uality 6ith &R channels"
ith dynamic HR service, the advantages of HR service can e fully utili;ed in
handling traffic urst and net6or capacity e?pansion"
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* 'atellite Ais Technology
1.3 HR Service Implementation
All Z7G-#'' e8uipments, including #'$ and #T', are designed 6ith good modular
structures" )t maes the system upgrade and e?pansion very easy, and provides
convenience for deploying ne6 functions and ne6 services"
)n ZTE #'' e8uipments, the HR service implementation is different from that of the
traditional &R-ased system in the follo6ing three aspectsB
Transcoder unit 9T$:
Ais interface unit et6een #'$ and #T'
#T' channel coding>decoding unit
&igure !"( -% illustrates the structure of Z7G!4-#'' system that reali;es HR service"
The HR frame structure of each node is descried in the figure"
Uplink: conversion from 8 kbps to 16 kbps
Downlink: conversion from 16 kbps to 8 kbps
BB
TT
SS
BB
SS
CC
TT
CC
UU
BB
SS
CC
RR
MM
MM
LA
BB
SS
CC
SS
CC
MM
MS supporting
HR-service
BB
TT
SS
BB
SS
CC
TT
CC
UU
BB
SS
CC
TT
CC
UU
BB
SS
CC
RR
MM
MM
BB
SS
CC
RR
MM
MM
OM-R Server OM-R lient
LA
BB
SS
CC
SS
CC
MM
BB
SS
CC
SS
CC
MM
!rocessing HR fr"me
#-interf"ce 6$
kbps voice c%"nnel
onfiguring HR&
perform"nce me"surement&
"n' service flow processing
16 kbps
HR c%"nnel
16 kbps
HR c%"nnel#bis interf"ce 8
kbps HR c%"nnel
Uplink: 'eco'e HR fr"me to 6$ kbps voice
c%"nnel
Downlink: enco'e 6$ kbps voice c%"nnel into
16 kbps HR c%"nnel
onfiguring HR&
perform"nce me"surement&
"n' relev"nt O(M
processing
&igure !"(-% 'chematic Diagram of Z7G!4-#'' 'ystem 9'upporting HR 'ervice:
)n Z7G!4-#'' system, as sho6n in &igure !"( -%, the HR service implementation
process in uplin direction is as follo6sB
The HR frame is processed y #T' first and then sent to R00 through Ais interface"
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G#C#T4*CE!C4 G'0 Advanced Technology
#)// performs the internal conversion from 2 ps channel to ! ps channel and
then sends the frame to #it-5riented '6itching
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* 'atellite Ais Technology
(" Add the T$ unit 9actually, the EDRT oard: that supports HR service" The EDRT
oard can automatically recogni;e the uplin voice coding format at Ais
interface" The do6nlin coding automatically adopts the same code as that in
uplin coding" )f the system has een configured 6ith the EDRT oard that
supports HR service, then such EDRT oards can support HR service only
through soft6are upgrade" )f the system has een configured 6ith oards that do
not support HR service through soft6are upgrade, then add the EDRT oard that
supports HR service, and the original oards can still e used to allocate &R
channels"
*" $ommissioning the HR service means e?panding the system capacity" Thus A-
interface capacity should e e?panded according to ne6 capacity planning"
0oreover, capacity e?pansion should e performed for the
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G#C#T4*CE!C4 G'0 Advanced Technology
system 6ill automatically allocate another resource instead"
The T$ that supports HR service also supports &R and E&R" After T$s related to&R and E&R are occupied, the system 6ill allocate T$s that support HR service to
satisfy &R and E&R re8uirements" After T$s that support HR service are
occupied, the system stops allocating HR radio resource, and allocates the &R
channel and E&R channel until the T$ resource that supports HR service is
availale"
1.& HR Service Applications
ith the HR service, rapid capacity e?pansion can e reali;ed on the current net6or
to relieve the pressure of radio net6or fre8uency ands and capacity, and solve the
traffic congestion" )n different situations, such as common capacity e?pansion or
handling emergency urst traffic, different strategies should e adopted"
!" HR applications in area 6ith urst traffic
The HR service is most effective in handling urst traffic in areas such as the
stadium, campus, or rende;vous" These areas all have the common feature that
the heavy traffic occurs periodically or suddenly" &or e?ample, the traffic
increases suddenly during a match in a stadium, and the traffic on campus
increases suddenly after class" The dynamic HR service is most appropriate to
apply in such situations" )n normal cases, the traffic is lo6, and the channel is in
&R status" hen the traffic increases suddenly, the channel automatically
converts to HR status, relieving the traffic congestion and avoiding the 6aste
that is usually caused y the common capacity e?pansion"
%" HR applications in area 6ith dense traffic
The traffic is dense in areas such as the dense uran area, airport, rail6aystation, and pla;a" ith the rapid development of net6or suscriers, the
re8uirement of capacity e?pansion in such areas also increases greatly"
)n order to avoid fre8uent net6or ad@ustment, the HR service can e adopted to
temporarily relieve the pressure of capacity e?pansion" #efore the ne?t capacity
e?pansion is performed, commissioning the dynamic HR or static HR can
handle the emergent capacity increase" The HR service, comined 6ith a long-
term planning and capacity e?pansion, provides a fle?ile choice for operators in
capacity e?pansion" 0oreover, the HR service is also a solution for net6or
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* 'atellite Ais Technology
capacity e?pansion for dense uran area 6here the fre8uency resource is limited
and the site e?pansion is infeasile"
(" HR applications in area 6ith lo6-end users
)n some areas 6ith lo6-end users such as the remote rural area, operators also
provide the coverage to enhance their competition po6er" Ho6ever, such areas
have sparse users and the Average Revenue /er User 9AR/U: is lo6, the ratio of
investigation to output of the operator is very lo6"
These lo6-end users do not have high re8uirement for the voice 8uality" Thus
the HR service 9static HR or dynamic HR: can e adopted together 6ith some
6ide-coverage technologies to reali;e a lo6-cost coverage"
5n the other hand, the urst traffic might occur in such lo6-end traffic areas,
such as capacity changes due to users= migration" The HR service can e used as
a practical solution for such prolems"
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2 Ultra'(istance Covera"e Tec%nolo")
2.1 Tec%nolo"ical Bac*"roun#
)t is specified in G'0 protocols that the ma?imum access radius of G'0 .44 0H;
system is (+ m, and the corresponding Time Advance 9TA: is (" 5n 'A$$H, TAs of
the ! header and the protocol message of each layer are all set in its"
'uch restrictions in G'0 protocols are mainly due to that the coverage larger than (+
m is difficult to reali;e in the G'0 .44 0H; environment, and can e reali;ed only
in some special propagation environments"
ith the evolution of G'0 protocols, there are more fre8uency ands" #ecause the
propagation loss of G'0 *44 0H; system is less that that of G'0 .44 0H; system, it
is specified that the coverage radius of the former can e larger than (+ m, the
ma?imum access radius of the former can e !%4 m, and the corresponding TA is up
to %!." &or the time eing, e?cept for G'0 *44 0H; system, other G'0 systems do
not support TA that is larger than ("
2.2 +rotocol Restrictions
This section introduces restrictions of the coverage distance in G'0 protocols"
2.2.1 Ra#io Inter,ace Restrictions
)n G'0 system, each carrier adopts the TD0A mode, that is, eight timeslots constitute
a frame, and the eight timeslots correspond to eight physical channels respectively, as
sho6n in&igure %"% -("
)S1 )S* )S+ )S$ )S, )S6 )S- )S.)S.)S- )S1
&rame
Time A?is
&igure %"%-( G'0 'ystem &rame Definition
During the call process, one user occupies one timeslot 9time 6indo6:, and at the ase
9
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station, each timeslot corresponds to a user" Thus the 0'-sent data that is received y
the ase station can only fall into the user=s time 6indo6, other6ise, the ne?t channel
6ill e influenced"
)f 0' is in the idle status, it does not no6 the distance from it to #T'" Therefore,
6hen sending the first access re8uest, 0' taes its o6n time 6indo6 as reference"
#ecause delay e?ists in space transmission, the time 6indo6 has a certain offset 6hen
the 0' signal actually reaches #T', that is, delay e?ists, as sho6n in &igure %"% -*"
)ot"l 'el"/
0"se st"tion
MS
Uplink 'el"/ Downlink 'el"/)ime
Sen' Receive
&igure %"%-* Access /ulse Delay
#T' has strict re8uirement for the time 6indo6" )n order to mae the 0' signal fall
into the receiving time 6indo6 of #T' efore it reaches #T', 0' must send the signal
ahead of time" #T' specifies the TA and sends it to 0'" The TA is in it unit"
The length of a TA is one yte" As specified in G'0 protocols, oth G'0 .44 0H;
system and G'0 !244 0H; system uses si? its to send the TA and the other t6o its
are reserved" Thus the ma?imum TA value is (, i"e" ( its, of 6hich each it e8uals
(". ms"
The space transmission delay includes uplin delay and do6nlin delay 9the uplin
distance e8uals the do6nlin distance:" The signal is transmitted at the velocity of
light" The ma?imum coverage radius is calculated as follo6sB
9( F (". F !4-: F ( F !42> %(+ m
Thus for G'0 .44 0H; system and G'0 !244 0H; system, the ma?imum coverage
radius is specified as (+ m in G'0 protocols" The follo6ing lists the restrictionsB
!" Restrictions of Access #urst 9A#:
&or the A# of 0', 0' sends it according to its o6n time reference TA 4"
0
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G#C#T4*CE!C4 G'0 Advanced Technology
PREMEASUREMENT REPORT
CHANNEL REQUIRED
HANDOVER DETECT
TALKER INDICATION
LISTENER INDICATION
HANDOVER COMMAND 9if the pre-synchroni;ation mode is adopted:
IMMIDIATE ASSIGNMENT
ASSIGNMENT COMMAND
PHISICAL INFORMATION
VGCS UPLINK GRANTED
PDCH ASSIGNMENT COMMAND
The aove messages are restricted y the condition TA I (, thus if TA J (, the
normal signaling processing 6ill e influenced"
2.3 Brea*t%rou"% Met%o#sThere are t6o methods to rea the restriction of coverage distance specified in G'0
protocols 9i"e" the ma?imum TA is (, or the ma?imum coverage radius of G'0 .44
0H; system and G'0 !244 0H; system is (+ m:"
#reathrough method !
Adopts G'0 *44 0H; system, or reali;es the method specified in G'0 *44 0H;
system in G'0 .44 0H; system"
#reathrough method %
#T' adopts the special radio channel mapping technology and improved #T'
receiving technology at radio interface, to guarantee there is no mutual interference
et6een #T's"
2.3.1 Brea*t%rou"% Met%o# 1
According to G'0 protocols, only the G'0 *44 0H; system can have TA that is
larger than ( and the ma?imum TA value is %!."
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* 'atellite Ais Technology
&or G'0 *44 0H; system, t6o fre8uency ands are defined in G'0 protocolsB G'0
*+4 0H; and G'0 *24 0H;" As to date, the G'0 *44 0H; system has not een
commerciali;ed"
The follo6ing lists the advantage and disadvantage of reathrough method !B
Advantage
'ince the specification in G'0 protocol is roen through, there is no capacity
limit 6hen reali;ing a coverage distance larger than (+ m"
Disadvantage
#ecause the G'0 .44 0H; 0' does not adapt to G'0 *44 0H; system,appropriate 0' is re8uired, ut it is difficult to reali;e in actual applications"
2.3.2 Brea*t%rou"% Met%o# 2
)f the coverage radius e?ceeds (+ m, then 0' must support TA J (" Ho6ever, the
ma?imum TA recogni;ed y G'0 .44 0H; 0' is ( its" )t is impossile to upgrade
all 0's, thus the restriction that the ma?imum coverage radius is (+ m can e roen
through y applying special radio channel mapping technology and improved #T'
receiving technology at the radio interface" )n other 6ords, #'' should e upgraded"
The follo6ing lists the advantage and disadvantage of reathrough method %B
Advantage
)t is easy to e applied ecause no change should e made in 0' and the cost is
lo6"
Disadvantage
A certain system capacity is sacrificed" )n normal cases, one carrier provides eight
channels" )f the coverage area is very large, there might not e eight channels" The
numer of channels depends on specific net6oring solutions"
The follo6ing introduces a simple and practical solutionB
)f the coverage radius of G'0 .44 0H; system is larger than (+ m, then t6o
timeslots are used to function as one channel to satisfy the re8uirement of a 4 m !%4
m coverage area" )n other 6ords, 6hen 0' sends a channel re8uest, the access urst
pulse received at #T' spans t6o timeslots, thus the control channel adopts t6o
physical channels, i"e" t6o consecutive timeslots"
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G#C#T4*CE!C4 G'0 Advanced Technology
The ma?imum TA value of 0' at the radio interface is (" )f the space delay is larger
than (, the time during 6hich the signal arrives #T' spans t6o timeslots, as sho6n in
&igure %"( -+" The dedicated control channel and the traffic channel also use t6o
ad@acent physical channels"
. . 11
Total space delayB ,(
. 6 -1 *
* + $ , 6 -
+ $ , .-6,
'ent y
#T'
'ent y
0'
'end 6ith a TA of ,( its
&igure %"(-+ Delay Relationships
$onsidering that #T' adopts t6o timeslots to process a user=s data, the second timeslot
is called e?tended channel, as sho6n in&igure %"( -"
% ( * + , 1 %
. . 11
&rame
E?tended channel
&igure %"(- E?tended $hannel
&igure %"( -1 sho6s the carriers after channel e?pansion" 5riginally, a TR7 can
provide eight physical channelsK after the channel e?pansion, a TR7 has four physical
channels, the carrier capacity is halved"
.
.
+*1
1 * + $ , 6 -Origin"l )R
23ten'e'c%"nnel )R
&igure %"(-1 Actual
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* 'atellite Ais Technology
can not reach !%4 m due to large propagation loss of G'0 .44 0H; system and
uplin>do6nlin alance prolems"
To restrict the upper-layer signaling, perform the follo6ing operationsB
Upgrade #'$ soft6are, and e?pand the TA field definition in the original messageK
Adopt the actual TA value at #T'K
&or a TA to e sent to 0', if TA I (, then send the actual TA value to 0'K if TA J
(, then al6ays send ( to 0'"
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3 -(- Tec%nolo")
3.1 (e,initions
Enhanced Data for G'0 Evolution 9EDGE: includes Enhanced General /acet Radio
'ervice 9EG/R': and Enhanced $ircuit '6itched Data 9E$'D:" EDGE is a method
used to improve the data transmission rate during G'0 radio connection"
Essentially, EDGE is only a ne6 modulating and channel encoding technology, 6hich
can e used to transmit /acet s6itching 9/': and $ircuit '6itching 9$': data>voice"
As an evolved G/R'-to-U0T' solution, EDGE enales the net6or operator to use
current radio net6or e8uipments to the ma?imum e?tent" )t also provides /$
multimedia communication services ahead of time efore the third generation moile
net6or ecome commerciali;ed"
3.2 Features
The system architecture of EDGE net6or is similar to that of G'0 net6or" Thefollo6ing lists features of the EDGE technology in the access service and net6or
estalishmentB
!" Access service
The and6idth is increased greatly" The pea transmission rate of moile data
service is up to (2* ps"
)t provides more precise net6or-layer positioning service"
%"
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communication control layer, and communication connection layer" The
interface et6een layers is standard" The hierarchical architecture maes the call
control and communication connection mutually independent" )t also fully uses
advantages of the pacet s6itching net6or, maing the and6idth allocation
closely related to the traffic" )t especially suits the o)/ service"
0edia Gate6ay 90G: is adopted in EDGE" 0G has the same functions as
'ignaling Transfer /oint 9'T/:, and can reali;e the signaling net6or
estalishment in )/ net6or" 0oreover, 0G is not only the interface et6een
G'0 circuit s6itching service and /'T< ut also the interface et6een Radio
Access
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* 'atellite Ais Technology
/hase %B provides real-time services not included in phase ! and adopts the ne6
modulating technology"
The EDGE standardi;ation, 6hich 6as initiated y ET')>'0G%, has started from the
feasiility research y Ericsson and
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G#C#T4*CE!C4 G'0 Advanced Technology
&igure ("*-2 2-/'3 0odulation 0ode
$ompared 6ith G0'3, 2-/'3 has the same symol rate, ut the it rate triples"
'ymol rateB %14"2(( sym>s
Timeslot it rateB 4 %%"2 ps 9G0'3:K 4 ." ps 92-/'3:
3.!.2 -(- Ra#io Bloc* Structure
&igure ("* -.sho6s the structure of EDGE radio loc"
&igure ("*-. EDGE Radio #loc 'tructure
3.!.3 C%annel Co#in"
The nine 0$'s of EDGE are categori;ed into three groups according to their
characteristicsB
&amily A 90$'-(, 0$'-, 0$'- 2, 0$'-.:
&amily # 90$'-%, 0$'-+, 0$'-1:
&amily $ 90$'-!, 0$'-*:
&or coding scheme structures in the same group, either one structure includes another
or eing included y another, 6hich maes it easy to reali;e conversion et6een
coding rates"
)n practical applications, alance should e ept et6een the transmission rate of valid
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* 'atellite Ais Technology
information and the valid transmission 8uality" The lo6-rate channel coding scheme,
6hich contains many redundancy error correction codes ut 6ithout transmitting much
valid information, is suitale for an environment 6ith poor transmission 8uality" &or
e?ample, on the edge of a cell, the lo6-rate G0'3 modulation method 0$'! * is
more suitale for compensating poor lin 8ualityK in the central area of a cell 6here
propagation conditions are good, the high-rate 0$' is often adopted"
As sho6n in&igure ("* -!4, EDGE has distinctive advantages over G/R'"
%%"*
%.",
**"2
+*"*
+."%
G0'3
2-/'3
overhead O protectionpayload of user
0$'-!
0$'-%
0$'-(
0$'-*
0$'-+
0$'-,
0$'-1
0$'-2
0$'-.
2"2
!!"%
!*"2
!1",
G0'3
$'-!
$'-%
$'-(
$'-*
2 2"2
!% !%"2
!*"* !+"%
%4 %4"2
G/R'
EDGE
&igure ("*-!4 EDGE vs" G/R'
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! Satellite A0is Tec%nolo")
!.1 vervie
)t is inconvenient to reali;e transmission in remote areas or islands" Usually, the
transmission et6een #T' and #'$ is reali;ed y the leased satellite lin"
!.2 Satellite Transmission Features an# Solutions
The follo6ing prolems 6ill e encountered 6hen the satellite lin is used to reali;e
transmission et6een #T' and #'$"
The delay of Ais lin is long" The information sent from the satellite ground
station is transferred through the satellite and then received y another ground
station" The end-to-end delay is not less than %4 ms, 6hich does not have much
to do 6ith the ground station=s position"
#ER
The satellite lin=s #ER is much larger than that of the ground lin" #ecause of
this factor and the influence of fading, the #ER change is very large" 5n the
other hand, the large delay and #ER on the transmission lin 6ill cause the
message throughput to drop"
$loc
The precision of the satellite Ais cloc is not very good"
The aove prolems do not occur 6hen the ground lin is used to reali;e transmission
et6een #T' and #'$, thus they should e resolved first"
'olutionB
#T' cloc
#ecause the precision of the cloc e?tracted from Ais interface is much less
than the cloc precision specified in G'0 protocols, such a cloc is not used to
synchroni;e #T' any more" )nstead, 6hen using the satellite lin to connect
Ais interface, the high-precision cloc source inside #T' is often used as #T'=
cloc source" )n other 6ords, the inner cloc of #T' is used for synchroni;ation"
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/rotocol timer
Ad@ust the interval of timers in some #T'>#'$ protocols to mae theseprotocols to adapt to large delay" The A/D timer of Ais is influenced most"
!.3 415'BSS Satellite A0is +rinciples
Z7G!4-#T' reali;es the satellite Ais y setting transmission modes through setting
D)/ s6itches at #T'" According to the D)/ s6itch setting, #T' sets corresponding
inner processing modes" #'$ automatically identifies the #T' processing mode and
performs relevant processing"
)n order to save the cost of satellite transmission, the satellite Ais often adopts Ais
multiple?ing mode to reduce the numer of timeslots at Ais interface"
!.! 415'BSS Satellite A0is +%)sical Con,i"urations an#Re6uirements
)nterface et6een #T' and satellite transmissionB E!" PG14(, 1+ Q
5nly some timeslots are used in this E!" The timeslots are allocated as follo6sB
&or a #T', the transmission capacity isB
$E))
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* 'atellite Ais Technology
!.$ 415'BSS Satellite A0is Con,i"urations
!.$.1 Timeslot Con,i"urations #urin" Commissionin" 7(I+ Sitc% Settin"8
The satellite Ais is identified y the !-it D)/ s6itch on the acplane of the
common shelf at #T'"
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G#C#T4*CE!C4 G'0 Advanced Technology
Tale *"+ -* sho6s the D)/ s6itching settings of #T' 9%: rac""
Tale *"+-* D)/ '6itch 'ettings of #T' 9%: Rac
!+ !* !( !% !! !4 . 2 1 + * ( % ! 4
)
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* 'atellite Ais Technology
'AE%C/5RTB the E! port of master cainet that connects 6ith slave cainet %
44B master cainet=s $ port
4!B master cainet=s D port
!4B master cainet=s E port
!!B master cainet=s & port
A#)'C/5RTB 50 port numer
44B port A
4!B port #
!4B port $
!!B port D
A#)'C05DEB transmission mode at Ais interface
4B common Ais transmission mode
!B satellite Ais transmission mode
A#)'CT'B 50 A/D timeslot on Ais interface
444B T'!
44!B T'(!
4!4B T'(4
4!!B T'%.
!44B T'%2
!4!B T'%1
!!4B T'%
!!!B T'%+
!.$.2 +recautions o, Ra#io +arameter Settin"s
After the satellite Ais technology is adopted, the delay at Ais interface increases,
6hich causes the duration of channel allocation to increase" To mae 0' successfully
access the net6or, 6hen setting MRA$H $ontrol /arameterN, set T,_-ntegeras (%
and Ma,_#etrans9the ma?imum times of retransmission: as *"
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