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EVDO Princple
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Customer Service Department of CDMA Division
EVDO Basic Principle
EVDO Overview
The Key Technologies of EVDO
The Commercial Application of EVDO
EVDO Network Structure
EVDO Channel
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Customer Service Department of CDMA Division
• What is the EVDO ?
• the advantages of the EVDO ;
• the difference of the 1x and EVDO;
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Customer Service Department of CDMA Division
Abbreviations Abbreviations
• 1xEV - EVolution of cdma2000 1X• 1xEV-DO - Data Only or Data Optimized• HDR - High Data Rate• HRPD - High Rate Packet Data• AN - Access Network • AT - Access Terminal • 3GPP2 C.S0024: cdma2000 High Rate Packet Data Air
Interface Standards
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Customer Service Department of CDMA Division
EV-DO EvolutionEV-DO Evolution
• Natural evolution of CDMA2000 1xNatural evolution of CDMA2000 1x• Enjoy surfing In 3G service ahead of timeEnjoy surfing In 3G service ahead of time
IS-95B CDMA2000CDMA20001xEV-DO1xEV-DO
IS-95AIS-95ACDMA2000CDMA20001xEV-DV1xEV-DV
CDMA2000-1xCDMA2000-1xRelease 0Release 0Release ARelease A
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Customer Service Department of CDMA Division
1xEV-DO basic features1xEV-DO basic features
• Allocate one 1.25MHz bandwidth, data only ;• Forward link rate: from 38.4kbps to
2.4Mbps , Reverse link rate: from 9.6kbps to 153.6kbps ;
• Same RF characteristic with 1x/IS-95 ;• Adopting a series revolutionary technique in air
interface to accelerate data traffic 。
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Customer Service Department of CDMA Division
EV-DO Exciting Feature(1)EV-DO Exciting Feature(1)
Feature Item CDMA 2000 1X(1.25M) EV-DO(1.25M)
Service Voice and data Data only
Transfer rate IS95<14.4kbps
1x<153.6kbps/307.2kbps
FL<2.4Mbps/3.1Mbps
RL<153.6kbps/1.8Mbps
Division multiplex CDM for both Forward: TDM+CDM,
reverse: CDM
Handoffs Hard Handoff and Soft Handoff Both in FL , RL
VHO in FL
Soft Handoff in RL
Power Control and
Rate Control
Fast Power Control Both
In FL , RL
No Rate Control
Rate Control + Power Control in RL
Rate Control in FL
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Customer Service Department of CDMA Division
Old handset can be used in new network, and new handset can be used in old network. Handset availability!
Backward and Forward CompatibilityBackward and Forward Compatibility
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Customer Service Department of CDMA Division
Leverage Current Investment: Sharing the same RF with 95/1X
Insert new EVDO channel cards and software upgradeFlexible Network Configuration:
Can be used as a stand-alone network or together with
an CDMA2000-1X network
EV-DO Exciting Feature(2)EV-DO Exciting Feature(2)
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Customer Service Department of CDMA Division
More Advanced Features of Rev. AMore Advanced Features of Rev. AImproved Forward Link
– Larger Payloads Drive Data Rates To 3.1Mbps– Improved MAC Supports Over 100 Users Per
Sector– Packet Division Multiplexing Improves
Performance In Good Channel Conditions
Improved Reverse Link– Up 1.8 Mbps Data Rate– Throughput and Latency Gains With Hybrid ARQ– Improved Packing Efficiency
Enhanced Quality of Service (QoS)– Inter-User – Priority by User– Intra-User – Priority by Application– Error Reduction in BTS– Admission Control– Adaptive Scheduler for delay sensitive Applications– Quick Connect with Adaptive Quick Start
Broadcast/ Multicast (BCMCS)– Multimedia content to multiple users
Improved support for real-time packet applications, including
VoIP, Gaming, Video Streaming
Can leverage advanced all-IP architectures, IMS support !
Enhanced capabilities to enable service flexibility and new
revenue generating features
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Customer Service Department of CDMA Division
• the commercial application of EVDO
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Customer Service Department of CDMA Division
1xEV-DO commercialization by CDMA operators
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Customer Service Department of CDMA Division
• the CDMA Development Process of ZTE
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Customer Service Department of CDMA Division
In November 2001, launched large-scale research and development in cdma2000 1xEV-DO products. In February 2002, launched research and development in cdma2000 base station system based on all-IP technology. In June 2002, ZTE, for the first time, exhibited complete cdma2000 1x EV-DO equipment on Hong Kong 3G annual fair.In October 2003, commissioned a field trial cdma2000 1x EV-DO.In June 2004, had the capability to supply cdma2000 1x EV-DO products in batch.In July 2004, commissioned a field trial cdma2000 1x Release A.In November 2004, put cdma2000 1x Release A and cdma2000 1x EV-DO products into commercial operation.In 2004, launched research and development in cdma2000 1x EV-DV products.
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Customer Service Department of CDMA Division
ZTE CDMA Wireless Solution
ZXC10-BSCB/PCF
ZXCBTS-M+ZXICS-C
Compact city zone
ZXC10-BTSB I2
ZXCBTS-M800
ZXC10-CBTS
ZXCBTS-RMBTS
ESU
RU_8
RU_2
ESU
RURU_1
ZXCBTS-M
ZXCBTS-R
ZXRPT-CSuburb or village
ZXC10-BTSB I1
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Customer Service Department of CDMA Division
South America
Brazil
Argentina
Nicaragua
……
South Africa
Kenya
Zambia
Angola
…...
North Africa
Algeria
Benin
Nigeria
……
Europe
Bulgaria
Norway
Turkey
……
CIS
Russia
Tajikistan
Uzbekistan
……
Asia Pacific
China
Indonesia
Mongolia
Vietnam
South Asia
Afghanistan
India
Pakistan
Nepal
……
CDMA 1X
CDMA 1X + EV-DO
CDMA 1X + GoTa
CDMA 1X + EV-DO +GoTa
EV-DO
Zte cdma2000 gobale application
Middle East
Egypt
Kuwait
Saudi Arabia
……
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Customer Service Department of CDMA Division
1.ZTE CDMA products have been successfully deployed in approximately 60 countries serving for approximately 100 operators, with a global capacity of 30 million lines for commercial use. Accordingly ZTE has become China’s largest telecommunication equipment exporter, and one of the leading CDMA equipment vendors in the world.
2.By December 2005, ZTE has captured 21.56% market share in China Unicom’s CDMA business, ranking third only next to Motorola (23.35%) and Lucent(22.14%).3.ZTE’s GoTa products have found widespread applications in over 20 countries such as Russia, Norway, Malaysia, etc. ZTE’s GoTa has become China-made digital trunking system with the widest applications home and abroad.
ZTE has built over 40 CDMA2000 1xEV-DO systems for commercial or trial use in more than 30 countries and regions such as Philippine, Vietnam, Pakistan, Mongolia, etc.
Zte cdma2000 gobale application
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Customer Service Department of CDMA Division
• EVDO Network Structure
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Customer Service Department of CDMA Division
AT
HLR
PDSN
AAA
BTS BSC PCF
MSC
A10/A11
HA
ANAAA
Access Network ( 1x and DO )
EVDO NETWORK STRUCTURE
AT : access terminal AN : access network , including BSC and BTS AN AAA : AAA server for access network
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Simple Network StructureSimple Network Structure (End to End IP)(End to End IP)
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Customer Service Department of CDMA Division
Difference with 1x Reference NetworkDifference with 1x Reference Network
1xEV-DO is data only, so no interface to MSC/HLRThe Packet Data Domain equipment ( PDSN 、 AAA 、
HA ) is same as 1X Independent Access network AAA server Two A interfaces added:- A12 for access system authentication- A13 for AT roaming home AN and Foreign AN interaction
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Customer Service Department of CDMA Division
1xEV-DO Channel Overview1xEV-DO Channel Overview
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Customer Service Department of CDMA Division
1xEV-DO Channel Overview1xEV-DO Channel Overview
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Customer Service Department of CDMA Division
1xEV-DO Channel Overview1xEV-DO Channel Overview
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Customer Service Department of CDMA Division
Forward Link Overview Forward Link Overview The transmission rate is the rate requested by AT on the reverse link. Dedicated to a single AT at any given instant of time.
Pilot is embedded in the traffic stream (as opposed to a continuous transmitted pilot in IS-95).
Paging and Sync Channels are combined into a single Control Channel whose messages are time multiplexed on the “single user” forward link.
Forward link transmission is organized as 26.66…ms frames. Each frame consists of sixteen 1.66…ms slots. Each slot contains 2048 chips. Each slot is divided into two half slots with 1024 chips each.
No soft handoff TDMed, full power and variable rate (38.4 kbps ~ 2457.6 kbps) Adaptive coding and modulation (R = ¼, 3/8, and ½; QPSK, 8PSK and
16QAM) Interleaving, puncturing, repetition and symbol demultiplexing
Quadrature Spreading, baseband Filtering and up-converting
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Customer Service Department of CDMA Division
Forward Channel StructureForward Channel Structure The 1xEV-DO forward channel structure
is of a time multiplexed of the following channels
– Pilot channel used by AT for all the following
Initial acquisition Phase & timing recovery Coherent demodulation and maximal ratio
combining – Medium access Control (MAC) consists
of three sub-channels: Reverse activity channel (RA) carries
reverse activity bit (RAB) stream Reverse power control (RPC), DRC Lock channel –user packets Traffic channel carries – Control channel carries messages
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Customer Service Department of CDMA Division
Forward Pilot ChannelForward Pilot Channel A Pilot channel is transmitted at all times by the sector on each
active forward channel. The Pilot channel is an unmodulated BPSK signal assigned
Walsh cover 0. The Pilot channel is sent as 96 chip bursts, each of which is
located at the center of each half slot. The Pilot channel is transmitted at the full sector power.
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Customer Service Department of CDMA Division
Forward MAC ChannelForward MAC Channel
MAC channel is a CDM of Reverse Activity (RA) channel and Reverse Power Control (RPC) channels/DRC.
MAC channel is composed of up to 64 orthogonal Walsh channels and distinguish its uses (control & traffic preamble etc.) .
The RPC Channel and the DRC Lock Channel shall be time-division multiplexed.
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Customer Service Department of CDMA Division
Forward MAC ChannelForward MAC Channel RA channel belongs to a kind of broadcast channel , it is
used to carry RAB information , controlling the reverse link’s payload dynamic . When AN finds the reverse payload too large , AN will transmit RA to AT and request AT adjust AT’s data rate;
RPC channel is used to carry reverse power control information ;
DRC Lock Channel carrys the information whether AN have received AT’s message, when AN cann’t demodulate AT’s message which is sent through DRC,AN will show AT send message anew;
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Customer Service Department of CDMA Division
MAC Channel and Preamble MAC Channel and Preamble Use Versus MACIndexUse Versus MACIndex
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Customer Service Department of CDMA Division
Forward Control ChannelForward Control Channel
The Control Channel Cycle period is 256 slots and synchronous with 1xEV-DO system time.
The AN transmits a Control Channel at a rate of 38.4 or 76.8kbps.
It is the combination of paging channel and sync channeling;
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Customer Service Department of CDMA Division
Time Division Multiplexed in FLTime Division Multiplexed in FL
In 1xEV-DO,the whole forward link is used as a shared “Fat Pipe”, TDMed by all users.
Specific time for which subscriber depending on the policy of forward transmission algorithm : Round Robin, maximize data throughput of sector.
AT 3
AT 4
AT 2
AT 1
BS 1
BS 2
USER LEVEL
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Customer Service Department of CDMA Division
Reverse Link OverviewReverse Link Overview Reverse link parameters
- Reverse channel frames are 26.66ms; - Packet size is fixed at 26.66…ms; - Each slot contains 2048 PN chips; Output power characteristics are similar to CDMA2000 1X
- Access channel operation is similar to CDMA2000 1X - Closed & open loop power controls the mean output power of pilot and
MAC channels - The power levels for data are adjusted based on selected data rate Traffic channel
- In-phase component is a CDM of pilot/RRI and ACK channels - Quad-phase component is a CDM of DRC and data channels - Independent gains on DRC and ACK channel relative to pilot
DRC gain range (-9dB to +6dB)ACK gain range (-3dB to +6dB)
Access channel is composed of pilot channel and data channel - In-phase component consists of the pilot channel - Quad-phase component consists of the data channel
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Customer Service Department of CDMA Division
Reverse Channel StructureReverse Channel Structure
Each Traffic is direct sequence spread by a distinct user PN code sequence.The Access channels are identified by a distinct Access channel PN sequence per sector.Code Multiple : Pilot = W016 , DRC=W816 , ACK=W48 , Data=W24
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Customer Service Department of CDMA Division
Reverse Access ChannelReverse Access Channel
The Access Channel is used by the access terminal to initiate communication with the access network or to respond to an access terminal directed message.
The Access Channel consists of a Pilot Channel and a Data Channel.
The access terminal shall transmit information on the Access Channel at a fixed data rate of 9.6 kbps.
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Customer Service Department of CDMA Division
Reverse Traffic Channel OverviewReverse Traffic Channel Overview
Data channel: ( Pilot )+ RRI + DRC + ACK + Data The Reverse Traffic Channel is used by the access
terminal to transmit user-specific traffic or signaling information to the access network. The Reverse Traffic Channel consists of a Pilot Channel, an RRI Channel, a DRC Channel, an ACK Channel, and a Data Channel.
The access terminal shall support transmission of information on the Data Channel of the Reverse Traffic Channel at data rates of 9.6, 19.2, 38.4, 76.8, and 153.6 kbps. The data rate used on the Data Channel is specified by the Reverse Traffic Channel MAC Protocol.
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Customer Service Department of CDMA Division
Reverse Traffic Pilot / RRI ChannelReverse Traffic Pilot / RRI Channel Pilot channel – Unmoduated symbols with binary value . – Giving an assistance coherent demodulation achieves better
receiver performance (reduces the required Eb/No) . RRI channel – Reports data rate of the current reverse link data packet. • Represented by 3-bit RRI symbol, sent once per data packet • One-to-one mapped to reverse data rates – Each RRI symbol maps into a 7-bit codeword. – Time multiplexed with pilot symbols on every slot.
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Customer Service Department of CDMA Division
Reverse Traffic ACK ChannelReverse Traffic ACK Channel The ACK channel transmits a ‘0’ bit if a data packet has been received
successfully, and a ‘1’ if not in order to indicate whether a data packet on the forward traffic channel has been received successfully.
The ACK channel is generated by taking a single ACK bit, repeating this bit 128 times;
The ACK channel bit is transmitted at 9.6kbps in response to every FTC preamble that the AT detects is directed to it;
By using ACK channel in RL, AN can early terminate multi-slot packet transmission , and increased the actual throughput, it is HARQ;
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Customer Service Department of CDMA Division
Reverse Traffic DRC ChannelReverse Traffic DRC Channel
AT sends the request of the desired data rate and best serving sector on the forward channel to AN over the DRC channel.
Desired serving sector in the Active Set is indicated by one of eight 8-ary Walsh functions.
Data rate is block encoded to yield 8-bit bi-orthogonal codewords. AT estimates C/I received forward channel and determines the
supportable data rate and the requested sector for transmission in the active set.
Only the sector requested will transmit packets to the AT, after receiving 2 consecutive DRCs from AT.
The sector sends a data packet with a preamble to the AT at the rate requested by the DRC in the preceding slot.
Once the sector starts sending packets to an AT, it must continue to do so until the packet Tx is complete or an Ack bit is received.
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Customer Service Department of CDMA Division
Reverse traffic data can be transmitted from 9.6kbps to 153.6kbps.
All data transmitted on the reverse traffic channel shall be turbo encoded, block interleaved, sequence repeated, and orthogonally spread by Walsh function W24(++--).
Reverse Traffic Data ChannelReverse Traffic Data Channel
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Customer Service Department of CDMA Division
Reverse Link Power ControlReverse Link Power Control Reverse Link is power controlled similar to IS-95 /
CDMA2000 1X. AT transmitted power which is determined by both
open-loop and close loop power control. Based on measurements of reverse link signal quality,
sector continually sends up/down power control bits to the AT .
Using closed loop power control achieved , AT adjusts its Pilot/MAC output power with 0.5 dB or 1.0dB step sizes, based on power control bit received on forward link from AN.
Open loop estimate based on received forward link power.
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Customer Service Department of CDMA Division
• The key Technologies
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Customer Service Department of CDMA Division
Time Division Multiplexed in FLTime Division Multiplexed in FL
• In 1xEV-DO , the whole forward link is used as a shared “Fat Pipe”, TDMed by all users.
AT 3
AT 4
AT 2
AT 1
BS 1
BS 2
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Customer Service Department of CDMA Division
Adaptive modulation and codingAdaptive modulation and coding
• 1xEV-DO can automatically adjust its FL data rate, modulation scheme, coding rate according to the feedback of FL channel SINR provided by AT.
• AT use DRC sub channel to inform AN
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Customer Service Department of CDMA Division
Fast Cell Site SelectionFast Cell Site Selection
At any instance there is only one serving sector that is transmitting data to a given AT ;
The serving sector is decided by AT and changes as the Forward channel’s SINR changed.
AT use DRC sub channel to infrom AN who is the serving sector
AP1AP1
AP4AP4
AP2AP2
AP3AP3
AP1AP1 AP2AP2
TimeTime
Serving APServing AP
t1t1
Serving AP changeServing AP change
Server before t1
Server before t1
Server after t1
Server after t1
current sector forward data rate
Pilot/MAC on FWD link Pilot/DRC/ACK/Traffic on REV Link
(AP’s in AT’s active set)
After handoff AP2 forward data rate
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Customer Service Department of CDMA Division
Serving Sector Selection illustrationServing Sector Selection illustration
Serving Sector Selection
-15
-14
-13-12
-11
-10
-9-8
-7
-6
-5
-4-3
-2
-1
01
2
3
0 2 4 6 8 10 12 14
time, sec
SIN
R, d
B
Sector 0
Sector 1
Serving Sector Index
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Customer Service Department of CDMA Division
Hybrid ARQHybrid ARQ
• By using ACK channel in RL, AN can early terminate multi-slot packet transmission , and increased the actual throughput.
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Customer Service Department of CDMA Division
Reverse link rate controlReverse link rate control
• In 1x EV-DO specifications, AT’s reverse rate can be freely adjusted by AT from 9.6kbit/s to 153.6kbits. In order to avoid all the AT become unavailable, the workload of reverse links must be constrained to prevent too many users in the same sector from transferring data to AN at a high rate.
NotBusy
9.6kbps
19.2kbps
153.6kbps
P1
38.4kbps
76.8kbps
P2 P3 P4
Busy9.6
kbps19.2kbps
153.6kbps
q1
38.4kbps
76.8kbps
q2 q3 q4
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Customer Service Department of CDMA Division
Reverse link Power controlReverse link Power control
• Power control is essential to the system maximization. The forward power control is not required in 1x EV-DO because of its constant power. Therefore, power control is mainly adopted by reverse channels.
• Reverse Power control includes
Opened-loop power control 、 Closed-loop power control 、
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Customer Service Department of CDMA Division
Virtual soft handoff in forward linkVirtual soft handoff in forward link
• In The forward Virtual Handoff, there’s only one sector sends data to the terminals at a particular time in the AT active set. According to the quality of each received pilot, AT can use the DRC_Cover to specify the sectors which are expected to transfer data. In AN, all the sectors within the active set are listening to the reverse channels of the AT. AN decides which sector is the Serving Sector of the AT according to the DRC channel received.
• There’s no signaling messages exchange between AN and AT in the forward Virtual Handoff as it is very quick. It only takes up one sector’s forward air resource at anytime. The usability of forward channels are improved significantly.
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Customer Service Department of CDMA Division
Dual Mode Operation with 1x/DODual Mode Operation with 1x/DO
• As 1xEV-DO supports only data traffic, a total voice and data solution needs integrating cdma2000 1x and 1xEV-DO ;
• Packet data traffic can be handoff from 1x to DO, and dual mode terminal can monitor both system’s control channel, so even active in DO system it will not lose any voice terminated calls in 1x system.
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Thank You !
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