2009-05Security Level: Internal CDMA2000 1xEVDO Principle Wireless Case & Training Department www.huawei.com HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Preface This course mainly introduces the development of EVDO, the air interfaces and key techniques. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 2 Reference <cdma2000 High Rate Packet Data Air Interface Specification> HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 3 Objective After this course, you will: Know about the development of EVDO; Be familiar with the air interfaces; Be familiar with EVDO key techniques; HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 4 Chapter 1 EVDO Overview Chapter 2 EVDO Air Interface Chapter 3 EVDO Key Technique HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 5 Data Service Development of CDMA 1xEVDV DL:3.1M UL:1.8M CDMA2000 1x DL:153.6k/307.2k UL:153.6k/307.2k CDMA2000 1xEV-DO DL:2.4M UL:153.6k 1xEV-DO Rev.A DL:3.1M UL:1.8M LTE DL:100M UL:50M EV-DO will replace EV-DV and become the development direction of CDMA. 1995 2000 2001 2004 2005 2006 2007 CDMA 2008 CDMA/TDM OFDM HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 6 1xEVDO Technical Features The average data rate can reach 0.65~1.5Mbps on the forward links, and the peak rate of EVDO Rel.0 can reach 2.4Mbps, and the data rate on the forward links of Rev.A can reach 3.1Mbps. On the forward link, Time Division Multiplexing (TDM) is mainly adopted and Code Division Multiplexing (CDM) is used as supplement. On the reverse link, CDM is mainly adopted and TDM is used as supplement. Full power transmission on the forward link and power is allocated to users in a TDM mode. Only one sector transmits data to a user at any time There is only packet domain in the network structure. EV-DO handoff types: forward virtual soft handoff; reverse soft handoff. Only Dormant handoff is supported between 1xEV-DO and 1x. Different frequencies are used in EV-DO and 1x. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 7 1xEVDO Application Video Call Voice Internet Online Games VOD 1xEV-DO Network HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 8 1xEVDO Performance Comparison Item Multiple Access Service Feature Forward Peak Rate Reverse Peak Rate Chip rate/carrier Coding Method Modulation method Frame length CDMA2000 1x CDMA on the forward and reverse links. Voice and data services 153.6kbps（RC3） 307.2kbps (RC4) 153.6kbps（RC3） 307.2kbps (RC4) 1.2288Mcps/1.25MHz Covolution、Turbo Forword:QPSK Reverse: HPSK 5ms,20ms,40ms,80ms soft, softer and hard handoff on the forward and reverse links. Forward: fast power control Reverse:open loop and closed loop. CDMA1x EV-DO Rel 0 Forward:TDMA+CDMA+HARQ Reverse: CDMA Packet data service 2.4576Mbps 153.6kbps 1.2288Mcps/1.25MHz Turbo Forward:QPSK,8PSK,16QAM Reverse:BPSK 26.667ms Forward: virtual soft handoff Reverse:soft,softer,hard handoff. Forward: no power control Reverse: open loop and closed loop. CDMA1x EV-DO Rev A Forward:CDMA+CDMA+HARQ Reverse:CDMA+HARQ Packet data service 3.072Mbps 1.8Mbps 1.2288Mcps/1.25MHz Turbo Forward:QPSK,8PSK,16QAM Reverse:BPSK,QPSK,8PSK 26.667ms Forward: virtual soft handoff Reverse:soft,softer,hard handoff, added with DSC channel. Forward: no power control Reverse: open loop and closed loop power control,added with T2P Handoff Power Control HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 9 CDMA2000 1xEVDO Network Structure Air Interface Source Access Network AN A8 A9 PCF A10 A11 PDSN Access Terminal AT A12 A13/A16 A17/A18 AN AAA Radius AAA Target Access Network AN AT: Access Terminal AN: In EV-DO,BSC and BTS together are called as AN.BTS is called AP (Access Point). AN AAA: It is used for device authentication. PCF: Packet Control Function. PDSN: Packet Data Serving Node. AAA: Authentication, Authorization and Accounting. Standards: Air interface: C.S0024-0 V4.0 A interface: A.S00080 V3.0 HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 10 1xEVDO Development There are Rel. 0 and Rev. A two versions: Rel. 0 optimizes the air interface techniques according to the features of wireless internet data service and thus supports high capacity and data rate services. Rev. A not only improves the data rate on the forward and reverse links, but also introduces the QoS mechanism for real time services. As a result, EV-DO Rev. A is capable of carrying real time multi-media services. In October, 2005,Huawei firstly presented self-research Rev.A EV-DO system in international telecommunication exhibition in Beijing. Till December,2007, Huawei has already signed 65 EV-DO contracts in the United States, India, Mexico and Russia. Huawei not only supports Rev.A which is compatible with EV-DO Rel.0, but also supports the evolution to the LTE. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 11 Summary 1. What is the development of CDMA data service? 2. What are the service differences between EVDO and 1x? 3. What are the differences between EVDO Rel.0 and Rev.A? 4. What are the differences in network structure between EVDO and 1x? HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 12 Chapter 1 EVDO Overview Chapter 2 EVDO Air Interface Chapter 3 EVDO Key Technique HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 13 Chapter 2 EVDO Air Interface 2.1 Air Interface Introduction 2.2 Application ~ Security Layer 2.3 MAC Layer 2.4 Physical Layer HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 14 Air Interface Protocol Stack Application Layer Stream Layer Provides the Signaling Application for transporting air interface protocol messages and the Packet Application for transporting user data. Provides multiplexing of distinct application streams. Session Layer Connection Layer Security Layer Provides address management, protocol negotiation, protocol configuration and state maintenance services. Provides air link connection establishment and maintenance services.. Provides authentication and encryption services. MAC Layer Physical Layer Defines the procedures used to receive and transmit over the Physical Layer. Provides the channel structure, frequency, power output, modulation, and encoding specifications for the Forward and Reverse Channels. Huawei Confidential Page 15 HUAWEI TECHNOLOGIES CO., LTD. Data Transfer of Air Interface UATI assignment and session setup EV-DO Session A EV-DO Session B EV-DO Session C Time Connection: Forward/reverse channels assignment Authentication and MAC-Index assignment Connection 1 Connection 2 Connection 3 Idle Connection 4 Time Message exchange: Data transfer. PDU1 PDU2 Dormant PDU3 Time UATI: Unicast Access Terminal Identifier PDU: Packet Data Unit HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 16 Basic Concept MAC Index: In EV-DO, the system supports that multiple users stay in active state at the same time, so MAC Index is used to identify different users in the forward links. PDU: Packet Data Unit. In EV-DO, PDU is used as the data transfer unit. In different layers, the definition of PDU is different. UATI: Unicast Access Termination Identifier, is used to uniquely identify AT in the AN. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 17 1xEVDO_REL.0 Channels CDMA 1X EV-DO Forward Reverse Pilot Medium Access Control Traffic Control Traffic Access Reverse Activity DRC Lock Reverse Power Control Pilot Medium Access Control Data ACK Pilot Data Reverse Rate Indicator Data Rate Control HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 18 1xEVDO_REL.0 Channels Forward Channels: TDM with supplement of CDM, including pilot channel, MAC channels, traffic channel and control channel. MAC channels include RA channel (indicating system reverse load), DRC LOCK channel (reverse DRC acknowledgement), RPC channel (carrying power control information of reverse traffic channel) Reverse Channels: CDM with supplement of TDM, including access channels and traffic channels. Access channels contain Pilot and Data Channels, which transmit the acquisition information of terminals. Pilot channel is used for relevant demodulation of reverse links and timing synchronization and data channel carries the terminal acquisition information. Traffic channels include Pilot, Data, MAC and ACK channels. MAC channel assists MAC layer to perform the rate control of forward and reverse channels. MAC channels include RRI (indicating reverse rate) and DRC (carrying the rate of forward traffic channel required from terminals). HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 19 Chapter 2 EVDO Air Interface 2.1 Air Interface Introduction 2.2 Application ~ Security Layer 2.3 MAC Layer 2.4 Physical Layer HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 20 Application Layer - Signaling Function and protocol: Provides signaling routing, reliable transmission, fragmentation and encapsulation. It includes SNP,SLP-D and SLP-F protocols. SNP: The Signaling Network Protocol (SNP) provides message transmission services for signaling messages. SLP-D: Signaling Link Protocol (SLP)- delivery layer, provides fragmentation mechanisms, along with reliable and best-effort delivery mechanisms for signaling messages. SLP-F: Signaling Link Protocol (SLP)- fragmentation layer, provides fragmentation mechanisms. Signaling Messages SNP-H SNP-P Application Layer SLP-D-H SLP-F-H SLP-F-P … SLP-D-P … SLP-F-H SLP-F-P P:payford H:header Stream Layer Stream Layer-P Stream Layer-P HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 21 Application Layer - Packet Function and protocol: Provide reliable transmission, mobility management and flow control functions and it includes RLP, flow control and location update protocols.. When original packet data passes through the application layer, only RLP performs fragmentation for data and the other two protocols do not process the data. The Radio Link Protocol (RLP) provides retransmission and duplicate detection for the data streams and effectively realizes the low error rate of data transfer in air links. Packet Data RLP-H RLP-P Application Layer Stream Layer-P Stream Layer P:payford H:header HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 22 Stream Layer Function: Identify applications with different QoS requirements and application streams with different priorities are multiplexed in connection layer. The stream layer identifier is only added in the head of data packets. Stream layer identifier is as follows: Stream0: Signaling application. Stream1: Service application. Stream Layer Stream Layer-H Stream Layer-P Session Layer-P Session Layer P:payford H:header HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 23 Session Layer Function: Be responsible for session protocol activation and assignment and protocol parameters configuration. Protocol: Session Management Protocol (SMP), Address Management Protocol (AMP) and Session Configuration Protocol (SCP). Session Layer Session Layer-P Connection Layer-P Connection Layer P:payford H:header HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 24 Connection Layer Function: Acquire the network, setup/maintain/release/monitor connections, and perform air-link management and mobility management. Prioritizes and encapsulates data received from the Session Layer and forwards it to the Security Layer.Decapsulate data received from the Security Layer and forwards it to the Session Layer. Format A Format B Connection Layer Connection Layer-P Security Layer-P Header Connection Connection Header Layer-P Layer-P Security Layer-P P:payford H:header PAD Security Layer HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 25 Security Layer Function: Provides key exchange between AT and AN, authentication service of AT and AN, and encryption services and provides public variables needed by the authentication and encryption protocols. The Security Layer adopts the Key Exchange Protocol, Authentication Protocol, Encryption Protocol, and Security Protocol to provide these functions. H H Encryption-P Authentication-P Security-P Security Layer-Packet T T T Security Layer H MAC Layer P:payford H:header T:tail HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 26 Chapter 2 EVDO Air Interface 2.1 Air Interface Introduction 2.2 Application ~ Security Layer 2.3 MAC Layer 2.4 Physical Layer HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 27 MAC Layer Function: Provide access and control of physical channels: Control Channel MAC Protocol defines the rules concerning access network transmission and packet scheduling on the Control Channel. Access Channel MAC Protocol defines the rules governing terminal access method and long code generation method. Forward Traffic Channel MAC Protocol defines the rules governing rate control and multiplexing and de-multiplexing mode of the Forward Traffic Channel. Reverse Traffic Channel MAC Protocol defines the rules the access terminal follows to assist the access network in acquiring the Reverse Traffic Channel. It also indicates the rules the access terminal and the access network use to select the transmission rate used over the Reverse Traffic Channel. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 28 MAC Layer – Control Channel MAC Protocol Data Encapsulation: Security Layer Security Layer-Packet CC-H MAC Layer-H MAC Layer-P … Security Layer-Packet MAC Layer-P PAD reserved …MAC Layer-H MAC Layer MAC Layer-Packet Physical Layer-P CCH Physical Layer P:payford H:header HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 29 MAC Layer – Access Channel MAC Protocol Data Encapsulation: Security Layer Security Layer-Packet MAC Layer-H MAC Layer-P FCS PAD reserved MAC Layer MAC LayerSegment reserved … MAC LayerSegment MAC Layer-P MAC Layer-P ACH Physical Layer P:payford H:header HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 30 MAC Layer – Forward Traffic Channel MAC Protocol Data Encapsulation: Security Layer Security Layer-Packet … Security Layer-Packet MAC Layer-H MAC Layer-P MAC Layer-T MAC Layer Physical Layer-P FTCH Physical Layer P:payford H:header T:tail HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 31 MAC Layer – Reverse Traffic Channel MAC Protocol Data Encapsulation: Security Layer Security Layer-Packet MAC Layer-P MAC Layer-T MAC Layer Physical Layer-P RTCH Physical Layer P:payford H:header T:tail HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 32 Chapter 2 EVDO Air Interface 2.1 Air Interface Introduction 2.2 Application ~ Security Layer 2.3 MAC Layer 2.4 Physical Layer HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 33 Forward Channel Characteristics 1.Time division multiplexing with code division multiplexing. Pilot, traffic, control and MAC channels and RPC and DRC lock are time division multiplexing. RPC/DRC lock and RA channels are code division multiplexing. 2. Forward dynamic rate control replaces power control. There are 9 rate levels in dynamic rate control. At any time, single user is served.: One user occupies the overall forward power. Adjust data rate according to the wireless environment. At any time, BTS supports full power transmission without power control. 3. Channel structure: Slot is the transmission unit and the time period of each slot is 5/3ms (1.67ms). Each slot contains 2048 chips. Every 16 slots consist of one frame.. With different rate requested by terminals, data from physical layer can be transmitted during 1, 2, 4,8 or 16 slots. Huawei Confidential Page 34 HUAWEI TECHNOLOGIES CO., LTD. Frame/Slot Structure of Forward Links System time Frame = 26.67 ms 1/2 frame = 13.33 ms 4 slot = 6.66 ms 2 slot = 3.33 ms 1 slot = 1.667 ms 2 Slots 4 Slots 8 Slots 16 Slots 0 1 5 2 3 4 5 5 6 1 Slot 7 8 9 5 10 11 12 13 5 14 15 Active Slot Data or control 400 chips MAC 64 Pilot 96 chips Pilot Data or control Data or control MAC MAC 96 400 chips 64 400 chips 64 chips MAC Data or control 400 chips 64 1024 chips = half slot 1024 chips = half slot Pilot MAC 64 96 MAC 64 Idle Slot Pilot MAC 64 96 MAC 64 HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 35 Forward Channel Index MAC-Index MAC-Index MAC Channel Code 0－1 2 3 4 5－63 Not used Not used Not used RA channel 76.8kbps control channel 38.4kbps control channel Not used Preamble Mapping RPC & DRC Lock Sub- For corresponding channel forward traffic channel. The MAC Index corresponds to the 64-ary and 32-ary Walsh code, which is used to identify the MAC channel and traffic/control channels. Control channels mainly transmit broadcast or terminal messages, and share the same physical channels with traffic channels. And terminals decides whether it is control channel or traffic channel according to the MAC index. MAC Index is sent in the first slot as the preamble. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 36 Forward Pilot Channel Pilot channel transmits all 0 information and it is modulated by W640. Different from 95/1x continuous pilot, EV-DO adopts burst pilot transmitted every half slot. Burst Pilot is transmitted with full power and because it is difficult to lock the burst pilot, protocol defines the access time of terminal is extended from 15s to 60s. Pilot channel is used for the network acquisition, modulation and link quality measure. AP Pilot Channel All 0 Bit Pilot Pilot Pilot Data or control 400 chips Pilot MAC 96 64 chips Pilot Data or control Data or control MAC MAC 96 400 chips 400 chips 64 64 chips MAC 64 Data or control 400 chips 1024 chips = half slot 1024 chips = half slot HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 37 Forward MAC Channel MAC channels include RA,DRC Lock and RPC sub-channels. RPC and DRC Lock sub-channels are TDM and spread with the same Walsh code and then they and RA channel are CDM. After the processing, it is called bit stream, which occupies 64 chips and is transmitted four times in every slot. RA is the system reverse load indicator. RPC carries the power control information of reverse traffic channels. DRC Lock indicates that whether the system correctly receives the reverse DRC information or not. RPC AP DRC Lock RA Data or control MAC Pilot 96 400 chips 64 chips Pilot MAC Data or control Data or control MAC 96 400 chips 400 chips 64 64 chips MAC Data or control 400 chips 64 Bit stream MAC MAC MAC MAC 1024 chips = half slot 1024 chips = half slot HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 38 Forward MAC Channel The power control frequency of PRC channel is 600Hz and is transmitted 7 times in 8 slots or 15 time in 16 slots. DRC Lock sub-channel is transmitted once in each 8 or 16 slot and it repeats 4-8 times. RA sub-channel is common channel and indicates the reverse load of sectors. Repetition Cycle 4 or 8 times Repetition Cycle 4 or 8 times DRC period 8 or 16 slots RPC for user1 DRC Lock for user1 RPC for user1 DRC Lock for user1 … … RPC & RA DRC Lock & RA RPC for user n DRC Lock for user n RPC for user n DRC Lock for user n RA RA HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 39 Forward Traffic/Control Channel Traffic and control channels are TDM. Control channel is transmitted once in every 16 frames. System decides the channel types according to the MAC Index. Traffic channel transmits user data and MAC Index of traffic channel is from 5 to 63. Control channel transmits signalling and system messages and MAC Index of control channel is from 2 to 3. The rate of control channel can be 38.4kbps and 76.8kbps. Traffic Channel AP Control Channel Data stream Data Data Data Data Pilot Data or control MAC 96 400 chips 64 chips Pilot Data or control Data or control MAC MAC 96 400 chips 400 chips 64 64 chips MAC Data or control 400 chips 64 1024 chips = half slot 1024 chips = half slot HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 40 Forward Channel Structure FTC or CC Encoder R=1/3 Or 1/5 Scrambler C D I Q I Channel Interleaver 16 Channels QPSK/ 8PSK/ 16QM Modulator C Q D Sequence Repetition/ Symbol Puncturing I Symbol DEMUX 1 to 16 32-Symbol BiOrthognal Cover with MACIndex i 16-ary Walsh Covers Walsh Channel Gain=1/4 Walsh Chip Level Summer Q I Walsh Preambles All 0’s Signal Point Mapping 0-+1 1---1 MAC Channel RPC Bits for MACIndex I 600*(11/DRCLockPeriod) bps 64-ary Walsh Cover for MACIndex i Sequence Repetition I 0 Q A Signal Point Mapping 0-+1 1---1 Signal Point Mapping 0-+1 1---1 Bit Repetition (Factor =RABLength) RPC Channel Gain G(i) DRCLock Channel Gain G(i) 64 to 1024 PN Chips per Physical Layer Packet for Preamble I Walsh Chip Level Summer Sequence Repetition ( Factor=4 ) Q Q Walsh B DRC Lock Bit Repetition (Factor=DRCL ockLength) Walsh Cover W464 RA Channel Gain Walsh Cover 0 MAC Channel RA Bits Signal Point Mapping 0-+1 1---1 192 PN chips/time slot Q 0 I Pilot Channel (All 0’s) Signal Point Mapping 0-+1 1---1 Huawei Confidential Page 41 HUAWEI TECHNOLOGIES CO., LTD. Data Encapsulation of Forward Traffic Channel Data Packet in Physical Layer 1024 bits Physical Layer-P 1002 bits FCS 16 bits TAIL 6 bits Data Packet in Physical Layer 2048 bits Physical Layer-P 1002 bits PAD Physical Layer-P 22 bits 1002 bits FCS 16 bits TAIL 6 bits Data Packet in Physical Layer 3072 bits PAD Physical Layer-P PAD Physical Layer-P Physical Layer-P 22 bits 22 bits 1002 bits 1002 bits 1002 bits FCS 16 bits TAIL 6 bits Data Packet in Physical Layer 4096 bits PAD Physical Layer-P PAD Physical Layer-P PAD Physical Layer-P Physical Layer-P 22 bits 22 bits 22 bits 1002 bits 1002 bits 1002 bits 1002 bits FCS 16 bits TAIL 6 bits HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 42 Physical Layer Parameters of Forward links Packet data (bits) 1,024 1, 024 1,024 1,024 1,024 2,048 Data rate 38.4 76.8 153.6 307.2 614.4 307.2 slot 16 8 4 2 1 4 2 1 Physical code Data rate modulation (bits) 1/5 1/5 1/5 1/5 1/3 1/3 QPSK QPSK QPSK QPSK QPSK QPSK 2,560 2,560 2,560 2,560 1,536 3,072 Symbol Size (symbol) 24,576 12,288 6,144 3,072 1,536 6,272 3,136 1,536 3,136 1,536 3,136 1,536 Preamble (chips) Repetition 1024 9.6 4.8 2.4 1.2 1 2.04 1.02 1 1.02 1 1.02 1 512 256 128 64 128 2,048 2,048 3,072 3,072 4,096 4,096 614.4 1,228.8 921.6 1,843.2 1,228.8 2,457.6 1/3 1/3 1/3 1/3 1/3 1/3 QPSK QPSK 8PSK 8PSK 16QAM 16QAM 3,07 2 3,072 3,072 3,072 3,072 3,072 64 64 64 64 64 64 2 1 2 1 Slot Multiplex Modes:SM1;SM2;SM3;SM4. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 43 Slot Multiplex Mode of Forward Physical Layer Preamble 64chips Pilot&MAC 224chips Pilot&MAC 224chips SM1 Data 336chips Data 800chips Data 400chips one slot 1536 Data Modulation Symbols Preamble 64chips Pilot&MAC 224chips Pilot&MAC 224chips Pilot&MAC 224chips SM2 One slot or multi-slots Data 336chips Data 800chips Data 400chips Data 400chips 3072 Data Modulation Symbols HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 44 Slot Multiplex Mode of Forward Physical Layer Preamble N chips Pilot&MAC 224chips Pilot&MAC 224chips Pilot&MAC 224chips SM3 Data 400-N chips Data 800chips Data 400chips Data 400chips 2560 or 3720 Data Modulation Symbols 2-4 Slots ,preamble is less than 400chips Preamble 112chips for 8 slots 624chips for 16 slots Pilot&MAC 224chips Pilot&MAC 224chips Pilot&MAC 224chips SM4 Preamble 400chips Data 668chips for 8 slots 176chips for 16 slots Data 400chips Data 400chips 2560 Data Modulation Symbols 2-4 Slots, preamble is more than 400chips HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 45 Forward Traffic Channel Process(307.2kbps/4 slots) 128 preamble chips Data flow after Modulation 6272 data chips divided into 4 TS First slot Interval Slot *2 Preamble 128 chips Data 272 chips MAC 64chips Pilot 96chips MAC 64chips Data 400chips Data MAC MAC MAC Pilot 96chips MAC 64chips Data 400chips 400chips 64chips Data 400chips MAC 64chips Pilot 96chips MAC 64chips Data 400chips Data Data Pilot 96chips MAC 64chips Data 400chips 400chips 64chips Final slot Data 400chips MAC 64chips Pilot 96chips MAC 64chips Data 400chips Pilot 96chips MAC 64chips Data 400chips 400chips 64chips 2048 chips Multiple users are TDM in traffic channels. Preamble should be sent in the first slot. Preamble is the repetition result of 32-ary Walsh code. preamble chips indicated by MAC index, is used to identify different users. Huawei Confidential Page 46 HUAWEI TECHNOLOGIES CO., LTD. Reverse Channel Characteristics 1. CDM is used in reverse channels with supplementary of TDM. Pilot and RRI channels of traffic channels are time division multiplexed, and Pilot/RRI, DRC, Data, ACK are code division multiplexed. Long code is used in access channel to identify users. Different from forward channels, frame (time period is 26.67ms) is the transmission unit of reverse channels. And the time of transmitting one packet is 16 slots, which is 1.667ms*16=26.67ms. 2. Reverse rate is adjustable and power control is adopted. Reverse rate is adjustable:153.6, 76.8, 38.4, 19.2, 9.6kbps, these five rate levels can be supported and Turbo coding and BPSK are adopted. The initial rate is generally 9.6kbps, and increases based on certain probability. Reverse power control and the function of reverse pilot are similar with 1x system. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 47 Reverse Access Channel Reverse access channel transmits the information of terminals which access the network. Access channels consist of Pilot and Data channels, and Pilot and Data is transmitted in I path and Q path respectively. Pilot is used for demodulation of reverse links modulation and timing synchronization, and helps terminals to access the network. It is all 0 bit stream transmitted continuously. Data carries the terminal access information and transmits physical packet data with the rate 9.6kbps. Pilot Access Data Access Probe Pilot Pilot-I Access Data-Q Capsule Frames Preamble Frames tp persistence probe 1 probe sequence 2 3 1 Np tp tp persistence 1 2 3 Ns Np Time ts persistence 1 2 3 2 Np ... HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 48 Reverse Traffic Channel Reverse traffic channels include Pilot/RRI, DRC, Data, ACK. Pilot and RRI are TDM, and Pilot/RRI, DRC, Data, ACK are CDM. Pilot and RRI are TDM:1 Slot = 2048 Chips, in which 256 chips for RRI ,1792 chips for Pilot. Pilot is all 0 bit stream and RRI indicates the rate of reverse traffic channels and is useful for demodulation at the BTS side. w 16 0 Pilot RRI Pilot Pilot Pilot RRI RRI 1 frame 16 Slots = 26.67 ms RRI 1.67 ms 1 Slot = 2048 Chips: 256 chips for RRI /1792 chips for Pilot (7:1) HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 49 Reverse Traffic Channel RRI,DRC,ACK channels are the dedicated control channels and MAC channels include RRI and DRC sub-channel. RRI channel reports the current rate of terminals. DRC channel is used to transmit the requested rate of terminal to the system. Data channel transmits packet data of reverse traffic channels and supports five rate levels from 9.6k to 153.6k.Turbo coding and BPSK are adopted. ACK channel indicates whether terminals receive the forward packet correctly or not and confirms the received packets. w 16 0 w 16 8 Pilot/RRI 1.67 ms DRC 1.67 ms 1.67 ms 1.67 ms w4 2 w 8 4 Data ACK 1/2 Slot 1.67 ms HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 50 Physical Layer Parameters of Reverse Links Code rate 1/4 1/4 1/4 1/4 1/2 Data Rate (kbps) 9.6 19.2 38.4 76.8 153.6 packet time period （ms） 26.67 26.67 26.67 26.67 26.67 Symbol rate 38.4 76.8 153.6 307.2 307.2 Data rate after modulation (kbps) 307.2 307.2 307.2 307.2 307.2 modulation BPSK BPSK BPSK BPSK BPSK slot 16 16 16 16 16 Packet bits 256 512 1024 2048 4096 Symbol 1024 2048 4096 8192 8192 HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 51 Reverse Access Channel Structure W 016 Pilot Channel ( All 0’s) 128 Binary Symbols per Physical Layer Packet Signal Point Mapping 0+1 1-1 W 24 I A Data Channel Physical Layer Packets 256 bits 9.6 kbps Encoder 1/4 1024 symbol Channel Interleaver 38.4 kbps Interleaved Packet Repetition 307.2 kbps Signal Point Mapping 0+1 1-1 Data Channel Correlation Gain Q B I A I’ Filter Spreading Q B Q’ Filter PNI PNQ Short PNQ Long PNQ Short PNI Long PNI HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 52 Reverse Traffic Channel Structure RRI Symbols One 3-Bit Symbol Per 16–Slot Physical Layer Packet Pilot Channel ( All 0’s) Simplex Encoder Codeword Repetition (Factor =37) 259 Binary Symbols per Physical Layer Packet W 016 T D M 7: 1 Puncture Last 3 Symbols 256 Binary Symbols per Physical Layer Packet Signal Point Mapping 0+1 1-1 128 Binary Symbols per Physical Layer Packet W 816 A 1.2288 Mcps 7 Binary Symbols per Physical Layer Packet DRC Symbols One 4-Bit Symbol Per Active Slot Bi-Orthogonal Encoder 8 Binary Symbols per Active Slot Codeword Repetition (Factor=2) 16 Binary Symbols per Active Slot Signal Point Mapping 0+1 1-1 B 1.2288 Mcps Walsh Cover W i8, i=0,…,7 W 48 DRCCover Symbols One 3-bit Symbol Per Active Slot ACK Channel 1 Bit Per Slot Bit Repetition Factor=128 128 Binary Symbols per slot (Transmitted in ½ Slot ) Signal Point Mapping 0+1 1-1 W 24 C 1.2288 Mcps Data Channel Physical Layer Packets Encoder Channel Interleaver Interleaved Packet Repetition Signal Point Mapping 0+1 1-1 D 1.2288 Mcps HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 53 Summary 1.Which channels does forward channels include? What are their characteristics? 2.What is the frame/slot structure of forward channels? 3.Please describe the slot multiplex modes adopted in forward links. 4.Which channels does reverse channels include? What are their characteristics? 5.Which rate does EVDO system support? HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 54 Chapter 1 EVDO Overview Chapter 2 EVDO Air Interface Chapter 3 EVDO Key Technique HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 55 Chapter 3 EVDO Key Technique 3.1 Time Division Multiplex 3.2 HARQ 3.3 Rate Control 3.4 Handoff HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 56 Time Division Multiplex Each slot is shared with different forward channels at different time and each channel transmits with full power. Different users share the slot resource and in each slot only the specific user is served by the system. In each slot, the user with best link quality is served considering the service fairness. In this way, higher multi-users diversity and system capacity can be achieved. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 57 Time Division Multiplex Power 614k AT _1 307.2k AT _2 1.2M AT _3 2.4M 1.8M 614k 614k AT _1 AT _3 307.2k Time AT _2 614k AT _1 614k Time AT _1 AT _1 307.2k AT _2 1.2M 2.4M 614k 614k 1.8M 307.2k Time AT _2 AT _2 1.2M AT _3 2.4M 1.8M 614k Time AT _3 Huawei Confidential Page 58 AT _3 HUAWEI TECHNOLOGIES CO., LTD. Chapter 3 EVDO Key Technique 3.1 Time Division Multiplex 3.2 HARQ 3.3 Rate Control 3.4 Handoff HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 59 HARQ DRC value requests 153.6 kbps R-DRC Channel One half slot offset 1st Slot F-Traffic Channel n n+1 n+2 n+3 2ndSlot n+4 n+5 n+6 n+7 3thSlot n+8 4thSlot n+9 n+10 n+11 n+12 n+13 n+14 n+15 Decode Failed R-ACK Channel Normal receiving 3 Slots delay NAK 3 Slots delay Decode Failed Decode Failed Decode Successful NAK 3 Slots delay NAK 3 Slots delay ACK Decode Failed R-ACK Channel Decode Failed 3 Slots delay Terminate in advance NAK 3 Slots delay NAK 3 Slots delay ACK HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 60 HARQ Combined with FEC (Forward Error Correction) and ARQ (Automatic Repeat Request) techniques, HARQ is adopted in EVDO system. In HARQ technique, data decoded incorrectly can be saved and combined with retransmitted data to improve probability of correct decoding. Incremental redundancy (IR) is introduced in HARQ. In IR technique, redundancy increases with the transmission times to improve probability of correct decoding. When transmitting data for the first time, high coding rate and low redundancy is adopted, and if the receiver does not decode it correctly, the data will be retransmitted with lower coding rate and higher redundancy; The receiver combines the data packets which contain the same information. This process repeats until that the data is decoded correctly or it reaches the maximum retransmission times. Multiple slots interleaving is also introduced in EVDO. There are 3 slots between neighbor transmission intervals which can be used to transmit new packets. Because of high decode complexity of Turbo, multiple retransmissions costs high latency. As a result, HARQ is limited in real time services. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 61 Chapter 3 EVDO Key Technique 3.1 Time Division Multiplex 3.2 HARQ 3.3 Rate Control 3.4 Handoff HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 62 Rate Control-Forward Principle of forward rate control: In each slot, terminals measure the SINR (C/I) of forward pilot and estimate the maximum rate supported by the forward links in the next slot, and then send the rate request to the BTS. BTS allocates wireless resource according to the requests from the terminals. So in forward links of EVDO, time slot is the unit of rate control. Rate allocation of Forward Links Rate supported by DO Rate supported by DOA HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 63 Rate Control-Forward Process: 1. 2. 3. 4. Pilot SINR evaluation: In each slot, the station delivers 96*2 bits of forward pilot signal. The terminal calculates the SINR (C/I) of the forward pilot. Channel evaluation: According to the signal noise ratio of the forward pilot in the past period, evaluate the signal noise ratio of the forward pilot in the next slot. According to the signal noise ratio threshold that is set or adapted, query from the table to get the maximum transmission rate that can be supported by the forward link in the next slot. The AT reports the values of DRC Value and DRC Cover to the AN through the DRC channel. The value of DRC Cover determines the sector that serves the AT. The AN learns the expected receiving rate from the DRC Value. Input of forward pilot channel Pilot C/I evaluation Channel evaluation Target FER Packet selection Threshold DRC request rate Adjustable C/I threshold error packet data of reverse traffic channel Serving Sector AT Decoding ACK HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 64 Rate Control-Reverse Process: 1. BTS measures ROT (Rise Over Thermal) of the reverse links in each frame and compares with the threshold to calculate the system current RAB. If the ROT exceeds the threshold, RAB=1;or else, RAB=0. 2. BTS send the RAB information to the served terminals through RA sub-channel of forward MAC channels. 3. Terminal combines the RAB information in the active set and indicate the reverse traffic MAC channels to choose the rate according to the defined restrictions. P1 P2 P3 P4 Not Busy 9.6 kbps 19.2 kbps 38.4 kbps 76.8 kbps 153.6 kbps If RAB = 0 (Not Busy), the transmission rate is increased at the probability p. q1 q2 q3 q4 Busy 9.6 kbps 19.2 kbps 38.4 kbps 76.8 kbps 153.6 kbps If RAB = 1 (Busy), the transmission rate is decreased at the probability q. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 65 Chapter 3 EVDO Key Technique 3.1 Time Division Multiplex 3.2 HARQ 3.3 Rate Control 3.4 Handoff HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 66 EVDO Handoff 1xEVDO handoff includes handoff inter-EVDO and handoff between 1x and EVDO. Inter-EVDO handoff: Forward links support virtual soft handoff; Reverse links support softer and soft handoff; handoff in dormant state between ANs; Handoff in active state between ANs. handoff between 1x and EVDO includes: handoff in dormant state between EVDO and 1x network, handoff in active state between EVDO and 1x network, handoff in dormant state from 1x to the EVDO network, in which handoff in active state from EVDO to 1x network is a indirectly handoff. It first switches to the dormant state, and then finishes the handoff. HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 67 Virtual Soft Handoff Virtual soft handoff: AT monitors the SINR of all the pilot signals in the Active Set at the same time, and choose the BTS with the largest SINR as the serving BTS. AT chooses the serving sector with the best quality and it only receives signaling and traffic data from this chosen sector. Through the DRC Cover information, cells know whether it is chosen or not. APB APA Serving AP change DRC DRC Serving AP AP1 AP2 APC Time AP: Access Point t1 HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 68 Summary 1.Which key techniques does EVDO include? 2.What is the application time division multiplex in forward and reverse links? 3.How to realize the HARQ technique? 4.What is the process of rate control forward and reverse links 5.What are differences of handoff between DO and 1x systems? HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 69 Thank You www.huawei.com