Mobilné systémy 3. generácie UMTS -...
55
Transcript of Mobilné systémy 3. generácie UMTS -...
Prehľad prednášok• UMTS
• HSDPA, EUL
• HSPA evolution
• LTE
• LTE-Advanced
Nasadené technológie• GSM worldwide (~ 720 networks)
– EDGE almost worldwide (~ 300 networks)
• UMTS (~ 300 networks)– HSDPA (~ 290 networks)– EUL (~ 90 networks)
• CDMA2000 (~ 250 networks)– EV-DO Rel.0 (~ 90 networks)– EV-DO Rev.A (~ 10 networks)
• FLASH-OFDM– USA, Slovakia
• Mobile WiMAX– South Korea (WiBro)– Sprint (2008)
IEEE 802.16
proprietary
3GPP2
3GPP
Dnešné možnosti• GSM/GPRS/EDGE
– mainly voice oriented service– downlink up to 300 kbps– uplink up to 200 kbps
• UMTS/HSDPA/EUL– higher voice capacity– UMTS DL/UL 384 kbps– HSDPA up to 28 Mbps– EUL up to 5,8 Mbps
• FLASH-OFDM– pure IP architecture– DL up to 5,3 Mbps– UL up to 1,8 Mbps
• CDMA2000 EV-DO– packet services only– DL up to 3,1 Mbps– UL up to 1,8 Mbps
• WiBro / Mobile WiMAX– packet services only– DL up to 3 / 10 Mbps– UL up to 1,2 / 2,5 Mbps
Prečo UMTS?
Prečo UMTS?
Prečo UMTS?
Evolúcia štandardov
GSM GPRS EDGE UMTS HSDPA EUL LTE
IS-95 CDMA2000 EV-DO rel.0 UMBEV-DO rev.A
FLASH-OFDM
802.16a (WiMAX) 802.16e (Mobile WiMAX)
3GPP
3GPP2
IEEE
Evolúcia štandardov
GSM GPRS EDGE UMTS HSDPA EUL LTE
EDGE EvoVoice evo
HSPA+
LTE-Advanced
IMT-2000
3GPP
3GPP spec. list
www.3gpp.org
Architektúra
RNC
MSC
HLR VLR AuC EIR
GMSC PSTN
RNC
SGSN
GGSN
Internet
IuB
Iur
IuCS
IuPS
UTRAN
Node B
UEMS
Node BBTSRNCBSC
UMTSGSM
Roadmap
Rel.99/4 Rel.5 Rel.6 Rel.7
HSPA+WCDMA HSPA+EULHSDPA
Rel.8
Latency (ms)
14
5.8
~50
42
12
~30
28
12
~30
14.4
0.384
~75
0.384
0.384
~150
UL Mbit/s
DL Mbit/s
HSPA+
Rel.9
168
24
~30
3GPP releases
MIMO, 64QAM,16QAM UL DC Comb
LTE
QPSK 16QAM multicode
3G – voice or data?Relative Network Load – RNC level
1
5
11
3
7
9
13
15
62843628466284962
Jan07
Mar07
May07
Jul07
Sep07
Nov07
Jan08
Mar08
May08
July08
Sep08
Nov08
Jan09
Packet data
Voice
Data is surpassing voice on 3G since 2 years
128 HSDPA networks50% at 3,6 Mbps
marginal 7,2 Mbps share310 HSDPA devices
221 HSPA networks> 30% at 7,2 Mbps55 EUL networks
800 HSPA devices
Rádiová prístupová sieť- UTRAN
• Komponenty– Node B– RNC
• Multiplexná technika– CDMA
• Duplexný mód– FDD– TDD
Funkcie Node B• Air interface Transmission / Reception• Modulation / Demodulation• CDMA Physical Channel coding• Micro Diversity (Soft Handover)• Error Handling• Closed loop power control
Funkcie RNC• Radio Resource Control• Admission Control• Channel Allocation• Power Control Settings• Handover Control• Macro Diversity (Soft Handover)• Ciphering• Segmentation / Reassembly• Broadcast Signaling• Open Loop Power Control
Duplexný mód• Frequency division duplex
+ symetric traffic (e.g. voice)+ higher average power
=> less Node Bs- higher complexity (HW)- channel measurements must be reported
• Time division duplex+ asymetric traffic (data)+ channel measurements are precise
- lower average power- strict synchronization needed- higher delays
FDD TDD
CDMA• Interference limited system• Sequences selection is crucial• Power control needed• Soft handover possible
• 5 MHz channel• 3,84 Mchip/s
Soft handover
Importance of Soft Handover
• Graphs show probability of excessive interference in neighbouring cell
• Active set size of 4 was agreed as mandatory for UEs
Why power control?• NEAR – FAR effect
– High interference between users & cell breathing
Power control
Choose throughput
Evaluate radio conditions
Required cell power
• Circuit switched services are guaranteed• Packet switched services are best effort
Power control• Open loop
– initial access to the network
• Closed loop– INNER loop
• Guarantee link quality (keep desired SIR)• 1500 times per second (Hz)
– OUTER loop• Minimize transmit power by setting SIR target for inner loop• Estimate SIR target based on BLER
Air interface protocol model
Channel concept
what type of data
how and with which type of characteristics
define the exact physical characteristics
BCCH, PCCH, DCCH, CCCH,DTCH, CTCH, …
BCH, PCH, RACH, FACH,DSCH, HS-DSCH, DCH, …
SCH, CPICH, PDSCH, HS-PDSCH,DPDCH, DPCCH, PRACH, …
new for UMTS, not in GSM/GPRS
Logical channels• Control channels
– Common (P2M)– Dedicated (P2P)
• Traffic channels– Common– Dedicated
Transport channels• Common channels
• Dedicated channel– DCH (UL & DL)
Physical channels• Synchronization• Pilot• Paging• Dedicated Physical Data Channel• Dedicated Physical Control Channel• High Speed Physical Downlink Shared Channel• …
Channels
downlink
uplink
Channel structure - UL
Channel structure - UL
Channel structure - DL
Channel structure - DL
Fyzická vrstva - DL
Channel Coding
Fyzická vrstva - DL
Spreading - UL
Modulation - UL
( )( ) ( )
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛−
⎟⎟⎠
⎞⎜⎜⎝
⎛++⎟⎟
⎠
⎞⎜⎜⎝
⎛−
=20
41
1cos41sin
CC
CCC
Tt
Tt
Tt
Tt
Tt
tRC
απ
απααπ
root-raised cosine (RRC) with roll-off α =0.22
RRCF impulse response
6 4 2 0 2 40.4
0.2
0
0.2
0.4
0.6
0.8
1
1.2
0
1
RRCF t( )
1− 1
t
normalized Tc = 1 (Tc = 26,042 μs)
Spreading - DL
Modulation - DL
( )( ) ( )
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛−
⎟⎟⎠
⎞⎜⎜⎝
⎛++⎟⎟
⎠
⎞⎜⎜⎝
⎛−
=20
41
1cos41sin
CC
CCC
Tt
Tt
Tt
Tt
Tt
tRC
απ
απααπ
root-raised cosine (RRC) with roll-off α =0.22
Codes
OVSF
Scrambling codes - UL(long code)
Scrambling - DL
Spreading & scrambling
Received signal
Detection
I = number of fingers of RAKE receiver
Measurements
Limiting factors• Downlink is power limited
• Uplink is interference limited
Common channels
Dedicated channels
max Node B power
Intercell interference
Intracell interference
max noise level
Power dynamics
Pnom
PCCH
100 ms
Services & RABs
Services & RABs• New service: Video Call
64/128/384PS Best Effort57CS Streaming64CS video call
12,2CS voiceRate [kbps]RAB type
