Download - 01CDMA Theory Unit Summary
-
7/25/2019 01CDMA Theory Unit Summary
1/38
Copyright 2003, ZTE CORPORATION
Unit summary about CDMA theory
-
7/25/2019 01CDMA Theory Unit Summary
2/38
Copyright 2003, ZTE CORPORATION
I. CDMA
Overview
-
7/25/2019 01CDMA Theory Unit Summary
3/38
Copyright 2003, ZTE CORPORATION
Frequency
reuse factor is
1;
network design
and expandingbecome much
easier
Advantages of CDMA(1)AMPS, D-AMPS, N-AMPS
CDMA
30 300 !"#
$00 !"#
$%0 !"#
3 Users
& Users
$0 Users
$
3'
'
3$
%(
)
*y+ia re/ueny euse N1)
*y+ia re/ueny euse N1'
*y+ia re/ueny euse N1
2unerabiity
C4I ) 56
2unerabiity
C4I $-' 56
2unerabiity
7b4No(--) 56
8SM
-
7/25/2019 01CDMA Theory Unit Summary
4/38
Copyright 2003, ZTE CORPORATION
Large capacity:
8--10 times than AMPS46 times than GSM
.re/uen,
y
*ime
Power
.re/ue
n,y
*ime
Power
.re/
uen,y
*ime
Power
DMA
*DMA
CDMA
FDMA---Different user use different
frequency
TACS AMPS
TDMA---Different user use different
time slot of one frequency
GSM
DAMPS
CDMA---Different user use same
frequency at the same time,but with
different spreading code
Advantages of CDMA(2)
-
7/25/2019 01CDMA Theory Unit Summary
5/38
Copyright 2003, ZTE CORPORATION
large coverage
almost 2 times than GSM, save money for
operator
Example:cover 1000 km2
GSM need 200 BTS
CDMA only need 50 BTSAttention: exact result need Link Budget
Advantages of CDMA(3)
-
7/25/2019 01CDMA Theory Unit Summary
6/38
Copyright 2003, ZTE CORPORATION
High privacy,hard to wiretapping
S+rea5 o5e
In9ormationsi:na
*;
Demo5uate5si:na
;
S+rea5 o5e
Spread signalEach user is belowthe noise deeply
Advantages of CDMA(4)
-
7/25/2019 01CDMA Theory Unit Summary
7/38Copyright 2003, ZTE CORPORATION
CDMA make before break---soft handoffOther systems: make after break---hard handoff
CDMA make before break---soft handoffOther systems: make after break---hard handoff
Use soft handoff, decrease drop-call rate
Advantages of CDMA(5)
-
7/25/2019 01CDMA Theory Unit Summary
8/38Copyright 2003, ZTE CORPORATION
Good voice quality, use 8k,13K(QCELP,EVRC)voice
codingthe best coding method in the world.
Voice quality(MOS)
6!PC"
#3!$%"
&!C'"A
#3!C'"A
&!EVRCC'"A
Advantages of CDMA(6)
-
7/25/2019 01CDMA Theory Unit Summary
9/38Copyright 2003, ZTE CORPORATION
Perfect Power Control and voice activation make the MS
Power low, healthy for human bodygreen mobile phone.
Advantages of CDMA(7)
Mean Power Max Power
GSM: 125mW 2W
CDMA: 2mW 200mW
-
7/25/2019 01CDMA Theory Unit Summary
10/38Copyright 2003, ZTE CORPORATION
-
7/25/2019 01CDMA Theory Unit Summary
11/38Copyright 2003, ZTE CORPORATION
II. CDMA
6ASIC PINCIP=7
-
7/25/2019 01CDMA Theory Unit Summary
12/38Copyright 2003, ZTE CORPORATION
Advantages of Spread Spectrum
Avoid interference arising from jamming signal or multi-
path effects
SS and demodulation, noise is suppressed and filtered
resist intercept and capture: difficult to detect
Achieve Privacy: Difficult to demodulate
Implement Multiple Access
Improve Freuency !euse "nlarge #apacity
-
7/25/2019 01CDMA Theory Unit Summary
13/38Copyright 2003, ZTE CORPORATION
Discriminating Among Forward
Code Channels
A Mobile Station receives a Forward Channel from a sector in aBase Station.
The Forward Channel carries a composite signal of up to 64 forwardcode channels.
Some code channels are traffic channels and others are overheadchannels.
A set of 64 mathematical codes is needed to differentiate the 64possible forward code channels.
The codes in this set are called Walsh Codes
SyncPilot
F$ %raffic&for user '()
Paging
F$ %raffic&for user '*)
F$ %raffic
&for user '+)
-
7/25/2019 01CDMA Theory Unit Summary
14/38Copyright 2003, ZTE CORPORATION
Discriminating Among Base
Station
A mobile Station is surrounded by Base Stations, all of them transmitting
on the same CDMA Frequency.
Each Sector in each Base Station is transmitting a Forward TrafficChannel containing up to 64 forward code channels.
A Mobile Station must be able to discriminate between different Sectorsof different Base Stations.
Two binary digit sequences called the I and Q Short PN Sequences (orShort PN Codes) are defined for the purpose of identifying sectors ofdifferent base stations.
These Short PN Sequences can be used in 512 different ways in a CDMAsystem. Each one of them constitutes a mathematical code which can be
used to identify a particular sector.
A
p to ./
#ode #hannels
p to ./
#ode #hannels
-
7/25/2019 01CDMA Theory Unit Summary
15/38Copyright 2003, ZTE CORPORATION
Discriminating Among Reverse
Code Channels The CDMA system must be able toidentify each Mobile Station that may
attempt to communicate with a BaseStation.
A very large number of Mobile Stationswill be in the market.
One binary digit sequence called theLong PN Sequence (or Long PN Code)is defined for the purpose of uniquelyidentifying each possible reverse codechannel.
This sequence is extremely long and
can be used in trillions of differentways. Each one of them constitutes amathematical code which can be used toidentify a particular user (and is thencalled a User Long Code) or a particularuser Reverse Traffic channel.
2 *ra99i9rom M.S.
>&3))3$00&2 *ra99i9rom M.S.
>$0000)30?on aess hanne >@
-
7/25/2019 01CDMA Theory Unit Summary
16/38Copyright 2003, ZTE CORPORATION
CDMA Spread Code Selection
ash Co5es
Short PNSe/uenes
=on: PNSe/uenes
*y+e o9Se/uene
Mutually0rthogonal
0rthogonal1ith itself atany time shiftvalue e2cept 3
near-orthogonalif shifted
S+eiaPro+erties
('
$
"owMany
./ chips(4(5,*33
sec6
+*,7.8chips*.-*4+ ms792 in *sec6
*/* chips/( days
=en:th
0rthogonalModulation
&information
carrier)
;uadratureSpreading&Sectors
DataScram?ling toavoid stringsof (=s or 3=s
orwar5 =in!untion
-
7/25/2019 01CDMA Theory Unit Summary
17/38Copyright 2003, ZTE CORPORATION
Information Stream
Speech
#oding
#hannel
#oding
Scram?le Spread
SpectrumModulation !F
transmit
#hannel
decoding
De-
scram?leDe-spread
SpectrumDe-
Modulation!F
receive
Information Stream
CDMA Communication Model
Speech
decoding
-
7/25/2019 01CDMA Theory Unit Summary
18/38Copyright 2003, ZTE CORPORATION
III. CDMA C"ANN7=
S*UC*U7AND MODU=A*ION
-
7/25/2019 01CDMA Theory Unit Summary
19/38Copyright 2003, ZTE CORPORATION
Upon completion of this lesson, the student will be able tomaster:
Objectives
-- *he 9orwar5 hanne in IS-
-
7/25/2019 01CDMA Theory Unit Summary
20/38Copyright 2003, ZTE CORPORATION
IS-95 CDMA Channels
-
7/25/2019 01CDMA Theory Unit Summary
21/38Copyright 2003, ZTE CORPORATION
Forward Channel Diagram
Convolutional
coder
Code
repeater
Group
interleaving
Convolutional
coder
Code
repeater
Group
interleaving
Short code
generator
Frequency
splitter
Frame quality
indicator
Coder tail
bit
Convolutional
coder
Code
repeater
Walsh 0 1.2288c!s
Walsh "2 1.2288c!s
#.8$s!s#.8$s!s2.#$s!s1.2$s!s
r%1!2& '%(
(.)$s!s
#.8$s!s
1(.2$s!s
(.)$s!s1(.2$s!s 1(.2$s!s
Walsh * 1.2288c!s
1(.2$s!s1.2288c!s
Group
interleaving
1(.2$s!s
(.)$s!s
#.8$s!s
2.#$s!s
r%1!2& '%(
(.)$s!s
#.8$s!s
2.#$s!s
1.2$s!s
(.)$s!s
#.8$s!s
2.#$s!s
1.2$s!s
(.)$s!s
#.8$s!s
2.#$s!s
1.2$s!s
(.2$s!s
#.#$s!s
2.0$s!s
0.8$s!s
ultiuse
1(.2$s!s
Frequency
splitter
1(.2$s!s
Frequency
splitter
+ong code
generator 1.2288c!s
800,-
Walsh n
1.2288c!s
*ilot Channel
all 0/
Sync Channel
*aging Channel
long code cloc$serm/ orard
traic channel
inormation bit
8.)$s!s
#.0$s!s
2.0$s!s
0.8$s!s
serm/ mas$ code
*oer control bit800,-
A
A
A
A
Forward Logic Channel
See ne3t page
-
7/25/2019 01CDMA Theory Unit Summary
22/38Copyright 2003, ZTE CORPORATION
4ase band
ilter
4ase band
ilter
5
6
7 7 t
6 t
cosct
sinct
7 path pilot *9 code
1.2288c!s
6 path pilot *9 code 1.2288c!s
S t
Forward Logic Channel
-
7/25/2019 01CDMA Theory Unit Summary
23/38
Copyright 2003, ZTE CORPORATION
Reverse Logic Channel
:ata
randomi-er
Frame quality
indicator
Coder tail
bit
Convolutional
coder
Code
repeater1(.2$s!s(.)$s!s#.8$s!s2.#$s!s
r%1!2& '%(
(.)$s!s#.8$s!s2.#$s!s1.2$s!s
(.2$s!s#.#$s!s2.0$s!s0.8$s!s
+ong code
generator
1.2288c!s
8.)$s!s#.0$s!s2.0$s!s0.8$s!s
Convolutionalcoder
Coderepeater
Groupinterleaving
Shortcode
generator
r%1!"& '%(
;rthogonalmodulator
Codertail bit
4ase band
ilter
4ase band
ilter
D
28.8$s!s28.8$s!s
4ase band
ilter
4ase band
ilter
D
Group
interleaving
;rthogonal
modulator
5ccess channelinormation bit88 bit per rame/
#.8$b!s#.#$b!s 1#.#$s!s
)# scale/
Walsh
sub code
#.8$s!s%"0
-
7/25/2019 01CDMA Theory Unit Summary
24/38
Copyright 2003, ZTE CORPORATION
Cdma2000 1xRTT Channel
-
7/25/2019 01CDMA Theory Unit Summary
25/38
Copyright 2003, ZTE CORPORATION
-
7/25/2019 01CDMA Theory Unit Summary
26/38
Copyright 2003, ZTE CORPORATION
Channel List: 1xRTT vs. IS-95@ IS-59 ?uilt on the IS-59A channels, and introduced t1o ne1 channels
Fundamental channel 1as the same as IS-5A traffic channel Supplemental code channels assigned to support rates a?ove
(/6/B?ps
@ IS-*333 (2!%% continue to ?uild on the IS-59 channels IS-59 channels continue to ?e supported in IS-*333 to support IS-59
mo?iles
Piot hanne
Syn hanne
Pa:in: hanne Aess hanne
orwar5 *ra99i Channe everse *ra99i Channe
un5amenta hanne un5amenta hanne
Su++ementa Co5e hanne ?-SCC"@ Su++ementa Co5e hanne ?-SCC"@
Su++ementa hanne ?-SC"@ Su++ementa hanne ?-SC"@
ui! Pa:in: hanne ?-PC"@ everse Piot hanne ?-PIC"@
IS-
-
7/25/2019 01CDMA Theory Unit Summary
27/38
Copyright 2003, ZTE CORPORATION
For1ard ;uicC Paging #hannel&F-;P#)For1ard Supplemental #hannel&F-S#)
!everse Pilot #hannel
!everse Supplement #hannel&!-S#)
Additional Channel in 1X
Commercial System
-
7/25/2019 01CDMA Theory Unit Summary
28/38
Copyright 2003, ZTE CORPORATION
Benefits of the CDMA2000 1x
Increased MS stand?y ?attery life &via ;uicC Paging#hannel)
se For1ard ;uicC Po1er #ontrol&via !everse Pilot
channel) %otal ?acC1ard compati?ility to reuse s1itch and call
processing features
*-+ d ?etter coverage
Provides igh speed (9+6. C?ps pacCet data capa?ilities
-
7/25/2019 01CDMA Theory Unit Summary
29/38
Copyright 2003, ZTE CORPORATION
I2. CDMA
E7F *7C"NO=O8F
-
7/25/2019 01CDMA Theory Unit Summary
30/38
Copyright 2003, ZTE CORPORATION
Contents
/6( Po1er #ontrol In #DMA
/6* Soft andoff In #DMA
-
7/25/2019 01CDMA Theory Unit Summary
31/38
Copyright 2003, ZTE CORPORATION
Why Power Control? All CDMA users occupy the same frequency
at the same time! Frequency and time arenot used as discriminators.
CDMA operates by using CODES todiscriminate between users.
CDMA interference comes mainly fromnearby users
Each user is a small voice in a roaring crowd-- but with a uniquely recoverable code.
Transmit power on all users must betightly controlled so their signals reach
the base station at the same signal leveland at the absolute minimum power levelnecessary to ensure acceptable servicequality
i:ure o9 Merit 74Io, 7b4No
?ener:y +er hi+ GbitH 4
inter9erene GnoiseH s+etra 5ensity@
CDMA 74Io-) to -$ 56
CDMA 7b4No(to) 56
i:ure o9 Merit 74Io, 7b4No
?ener:y +er hi+ GbitH 4
inter9erene GnoiseH s+etra 5ensity@
CDMA 74Io-) to -$ 56
CDMA 7b4No(to) 56
-
7/25/2019 01CDMA Theory Unit Summary
32/38
Copyright 2003, ZTE CORPORATION
Goals of the Power Control- To maintain the transmit power at no higher than the demand.
Each user doesn't get any more than the minimum Eb/ Io, to make
the smallest contribution to the total noises seen by other users as
possible.
Effective power control maximise the capacity of the system.
- To reduce the effect of fading.
- To solve the near-far effect.
?
-
7/25/2019 01CDMA Theory Unit Summary
33/38
Copyright 2003, ZTE CORPORATION
Power Control Types
Reverse Power Control
;pen=loop *oer Control
Closed=loop *oer Control(Forward traffic Channel)
Outer-loop Power Control
Inner-loop Power Control
Forward Power Control
6S=(@ *oer Control
6S=2000 Fast *oer Control >everse *ilot Channel/
Outer-loop Power Control
Inner-loop Power Control
-
7/25/2019 01CDMA Theory Unit Summary
34/38
Copyright 2003, ZTE CORPORATION
Summary of Power Control
All types of po1er control 1orC together to minimiEes po1er consumption
at the mo?ile stations, and increases the overall capacity of the system
transmit po1er6
F"! F"!
Mobie 6*S 6SC
Si:na Stren:th
Measurement
Set+oint
or
A5Just w5.
+ower
everse Outer
=oo+ Power
Contro
everse Cose5 =oo+
Power Contro
orwar5 =in! Power Contro
everse O+en =oo+
Power Contro
-
7/25/2019 01CDMA Theory Unit Summary
35/38
Copyright 2003, ZTE CORPORATION
Contents
/6( Po1er #ontrol In #DMA
/6* Soft andoff In #DMA
-
7/25/2019 01CDMA Theory Unit Summary
36/38
Copyright 2003, ZTE CORPORATION
Handoff
andoff is the process ?y 1hich a mo?ile station maintainscommunications 1ith the Mo?ile %elephone S1itching
center&MS#), 1hen traveling from the coverage area of one
?ase station to that of another
andoff Ceep the call esta?lished during the follo1ingconditions:
Su?scri?er crosses the ?oundaries of a cell
Su?scri?er e2periences noise or other interference
a?ove a specified thresholdA ?ase station component e2periences an out-of-service
condition during a call
-
7/25/2019 01CDMA Theory Unit Summary
37/38
Copyright 2003, ZTE CORPORATION
CDMA Handoffs
Durin:a Ca
I5e "an5o99
So9t "an5o99
So9ter "an5o99
CDMA-to-CDMA "an5o99
Inter-System So9t "an5o99
CDMA-to-Anao: "an5o99
hie in the
I5e State
-
7/25/2019 01CDMA Theory Unit Summary
38/38
Different types of handoffSC
4SC 4AS SBC
;C;:
. CB C5>. AD*B hando/
S SS D S D S Soter
S S S : S : D ,al sot
S S D : S :S
Sot
S S : : D : D ,ard
S D : : S : S Sot
S: : : D : S ,ard