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Purpose

Purpose. Introduce IS-2000 in terms of basic features or capability supported Standard is not organized by features, but rather they are largely hidden in specification wording Assuming knowledge of IS-95 Focus on differences and enhancements from IS-95

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Purpose

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  1. Purpose • Introduce IS-2000 in terms of basic features or capability supported • Standard is not organized by features, but rather they are largely hidden in specification wording • Assuming knowledge of IS-95 • Focus on differences and enhancements from IS-95 • A high-level description intended for internal and external audiences

  2. Third Generation (3G) Terms and Conventions • Spreading Rate • Spreading Rate 1 (1x) • Forward and Reverse Channels use DSSS carrier at 1.2288Mcps • Spreading Rate 3 (3x) • Forward Channel uses three DSS carriers at 1.2288Mcps each • Reverse Channel uses one DSSS carrier at 3.6864Mcps • RTT: Radio Transmission Technology • Collection of air interface technologies for telecommunication systems • 1xRTT EV-DV: • RTT: Radio Transmission Technology • EV: 1xEVolution is the migration path of 1x systems to higher packet data rates • DV: Data and Voice • 3GPP2: 3G Partnership Project 2 • Collaboration of many Standards Development Organizations • Global specifications for IS-41 based networks

  3. Goals for 3G CDMA • Backward compatible to IS-95 • Enhanced Wireless Services • Voice • Circuit Switched Data • Packet Switched Data • Double the voice capacity • Data rates up to 2Mbps

  4. CDMA 2000 Family of Standards • Release 0 – Completed 7/1999 • First 3G CDMA specification • Completed under a tight schedule • Not all physical layer features are supported by the signaling specification of Release 0 • Today’s CDMA 1x typically offer up to 153kbps data rate, upload and download • Release A – Completed 3/2000 • Contain signaling support for the entire Release 0 physical layer • Technically, Release A is the first complete 3G CDMA air interface specification • Most people consider Release 0 as the baseline 3G standard today

  5. CDMA 2000 Family of Standards • Release B • A small release that served the purpose to timely introduce some urgent carrier requirements • Release C – Completed 5/2002 • 1x EV DV (1xRTT Evolution, Data and Voice) was first introduced • Allows up to 3.1Mbps on the forward link • Release D • DV reverse link improvement • Close to completion

  6. 1x EV DO (1xRTT Evolution, Data-Only) • A separate series of specification that belongs to the CDMA2000 family of standards – (IS-856) • A completely different air interface standard but operate on the same 1xRTT spectrum • Both 1x and 3x are included in IS-2000, although 3x is becoming obsolete and no longer of interest to any carriers • Different than 1x EV DV, it requires a complete 1.25MHz CDMA carrier • Baseline 1x EV DO spec was published in 2001 • A new release, namely 1xEV DO Release A is currently under going standardization, targeting major reverse link improvements

  7. CDMA2000 versus WCDMA Even though both are based on CDMA technology they are significantly different: • Spreading rate is 3.84Mcps (versus 1.2288Mcps) • BS not Synchronized to GPS time • Core network is GSM MAP based (versus ANSI-41) • Vocoders are different

  8. Agenda • CDMA2000 Protocol Layers • Air Interface Physical Layer • Data Multiplexing • Power Control Enhancements • Rel. C Features

  9. CDMA 2000 Protocol Layers • IS-95 mixes layers • CDMA 2000 separate different layers • One of the most visible feature from the specification itself • Architecture impact to implementation • CDMA 2000 Layers • PHY: Physical Layer - cdma2000 volume 2 • MAC: Medium Access Layer - cdma2000 volume 3 • LAC: Link Access Layer - cdma2000 volume 4 • L3: Layer 3 Signaling - cdma2000 volume 5

  10. CDMA2000 Protocol Layers

  11. Agenda • CDMA2000 Protocol Layers • Air Interface Physical Layer • Logical and Physical Channel Naming • New Physical Channels • Radio Configurations • Variable Walsh Spreading • Quasi-Orthogonol Codes • Turbo Coding • 5 ms Frame Support • Modulation Differences • Data Multiplexing • Power Control Enhancements • Rel. C Features

  12. Logical vs. Physical Channels • Forward Link and Reverse Link • Forward Link: BS to MS, written in f-<chan> or F-<CHAN> • Reverse Link: MS to BS, written in r-<chan> or R-<CHAN> • Logical Channels • Always written in lower case • csch: common signaling channel, include f-csch and r-csch • Signaling channel shared by more than one MS • dsch: dedicated signaling channel, include r-dsch and f-dsch • Signaling channel assigned to one MS • dtch: dedicated traffic channel, include f-dtch and r-dtch • All traffic channels, prior to Rel D, are usually dedicated to one user/MS • Physical Channels • Expressed in capital letters

  13. Physical Channels Naming – Common Channels Forward Common Channels • F-PICH Pilot channel, same as IS-95 • F-SYNC Sync Channel, same as IS-95 • F-PCH Paging Channel, same as IS-95 • F-CCCH Common Control Channel • F-BCCH Broadcast Control Channel • F-CACHChannel Assignment channel • F-CPCCHCommon Power Control channel • F-QPCHQuick Paging channel • F-TDPICH Tx Diversity Pilot channel • F-APICH Dedicated Auxilary Pilot channel • R-ATDPICH Aux Tx Diversity Pilot channel Reverse Common Channels • R-ACH Access Channel, same as IS-95 • R-PICH Reverse Pilot channel • R-CCCHReverse Common Control channel • R-EACHReverse Enhanced Access channel

  14. Physical Channels Naming – Traffic Channels • Forward and Reverse • F/R-FCHFundamental channel • F/R- DCCHDedicated Control channel • F/R- SCHSupplemental channel • F/R- SCCH Supplemental Code channel (same as IS-95B)

  15. Logical to Physical Channel Mapping • MAC function maps logical channels with one or more physical channels • Dedicated channels are setup for each call

  16. New Physical Channels: Reverse Link Pilot Channel • R-PICH is used by the BS receiver to estimate the carrier phase and perform pilot added coherent demodulation • Increase in Reverse Link Capacity • The IS-95 reverse link transmission is based on non-coherent detection • R-PICH can be used to estimate the energy of the received traffic channel and to perform reverse link inner loop power control

  17. New Physical Channels: Forward Link Transmit Diversity • Transmit Diversity increases the Forward Link Capacity since a lower Eb/N0 is required • Transmit Diversity reduces the effects of deep fades since each path is separated in space or time; requires two antennas • Two methods are optionally provided for: • Space Time Spreading (STS) Transmit Diversity • Uses an orthogonal subsequence so that all symbols are transmitted on both antennas • Orthogonal Transmit Diversity (OTD) • Splits the symbols into two streams. Each stream is spread with a different Walsh sequence and transmitted via a different antenna. • OTD auxiliary pilot is required to support the second antenna – not expected to be used

  18. New Physical Channels: Quick Paging Channel • QPCH is introduced to decrease the wake time of a MS in slotted mode, that is the time the MS has to periodically demodulate the PCH or F-CCCH. • Increase MS battery life • MS monitors Paging Indicators on an assigned QPCH slot based on its IMSI. The QPCH slot proceeds its assigned PCH slot by 100 ms. • BS sets the PI bit to the ‘ON’ state to inform the MS that it should receive the F-CCCH or PCH in the next slot • Compared with demodulating 1 or 2 80ms PCH/F-CCCH frame • Tradeoff: Requires additional Forward Link Channel and may introduce signaling latency

  19. New Physical Channels: Access Channel Enhancements Four new physical channels: R-EACH, R-CCCH, F-CACH and F-CPCCH were introduced to support four different types of new access modes on top of the basic IS-95 access methods. • Basic Access (BA) mode is mandatory • R-EACH is required for this mode • Reservation Access (RA) mode is mandatory • R-EACH, R-CCCH, F-CACH and F-CPCCH are required for this mode • Power Controlled Access (PCA) mode (Rel. B) • R-EACH, F-CACH and F-CPCCH are required for this mode • Designated Access (DA) mode (Rel. B) • R-CCCH, F-CCCH and F-CPCCH are required for this mode Access Channel Enhancements reduces probability of packet collision.

  20. New Physical Channels: New Traffic Channels • Three new dedicated traffic channels: FCH, DCCH and SCH. • All traffic channels are code multiplexed. • The independent gain settings and QoS requirements such as FER or BER on the traffic channels can be set independently for optimal allocation of link resources. • Benefits: • Compared to IS-95, IS-2000 Dedicated Traffic Channels allow flexible support of different services in a more efficient manner. • SCH allows the transport of scheduled high speed data. • DCCH allows better voice quality for premium voice services and can reduce packet scheduling delay.

  21. New Physical Channels: New Traffic Channels • The FCH supports variable-rate transmission with blind rate detection • Maximum data rate is 9.6 or 14.4 kbps for Rate Set 1 or 2 • The SCH is used to carry data traffic in circuit or packet mode • SCH data rate is a multiple (1x, 2x, 4x, 8x, or 16x) of the fundamental data rate used by the corresponding FCH or DCCH, that is, either 9.6 or 14.4 kbps for Rate Set 1 or 2, respectively. • The data rate of the SCH must be scheduled using signaling, unlike the FCH that employs variable-rate transmission with blind rate detection. • DCCH is a dedicated channel for signaling and mini-signaling messages directed to a particular user • Can be in Discontinuous Transmission Mode (DTX) when no signaling data is to be sent • Possible to share the same F-DCCH for multiple mobiles on time-shared basis to conserve the Walsh Code resource • Although DCCH may also carry regular voice or data traffic, it should typically be reserved for signaling

  22. New Radio Configurations • Radio Configurations (RC)are introduced to specify a given code rate, modulation, and spreading rate. • The IS-95 Rate Set 1 and Rate Set 2 replaced by Radio Configurations for Forward and Reverse Links. • Forward Link: RC 1-5 for 1x and RC 6-9 for 3x • Reverse Link: RC 1-4 for 1x and RC 5-6 for 3x Forward Link Radio Configurations * per Supplemental Channel C= Convolutional, T = Turbo

  23. New Radio Configurations Reverse Link Radio Configurations * per Supplemental Channel C= Convolutional, T = Turbo • The requirements to support IS-2000 RC are as follows: • IS-95 compatible mode: F/R (1,1) and (2,2) • 1x cdma2000 mode: F/R (3,3), (4,3), and (5,4)

  24. Walsh Code Notation and Generation • Walsh codes generated using tree structure: • Walsh code Wim represents a Walsh code of length m using index I • IS-95 uses length 64 Walsh Codes • cdma2000 uses variable length Walsh Codes with base rate 128 (Wi128)

  25. Variable Length Walsh Codes • Variable length Walsh spreading achieves higher data rates on the forward link • Assigning a shorter Walsh function to a user while increasing the data rate results in a constant chip rate • Shorter codes are higher up in the tree structure, longer codes generated from this code can not be used at the same time (maintain orthogonality between channels) • Improved Walsh resource utilization: Certain code channels such as the Auxiliary pilot may be spread using a long Walsh function, which can enlarge the set of Walsh resources

  26. Variable Length Walsh Codes • Some cdma2000 Forward Link Channel Walsh Codes • Forward Pilot W064 • Quick Paging Channel W80128 • Transmit Diversity Pilot W16128

  27. Quasi-Orthogonal Function (QOF) • Forward Link may run out of Walsh code space • Increased capacity improvements • Additional overhead channels • Variable Walsh code spreading • Quasi-Orthognoal Function can be used to enlarge the number of code channels • Generated by multiplying Walsh Codes by masking functions with QPSK symbols. QOF’s are not orthogonal to the Walsh space but are close to orthogonal (“Quasi”). • QOF is mandatory for IS-2000 mobiles. A 2-bit QOF field is added in Extended Channel Assignment (ECAM) and Universal Handoff Direction Message (UHDM) to support QOF assignment

  28. Turbo Codes • Turbo codes require lower Eb/No than traditional convolutional codes at a high rate – Increased capacity! • In IS-2000 turbo codes can be used on SCHs, typically when the data rate  19.2 kpbs • Turbo codes generated using two parallel convolutional encoders with an interleaver before the second encoder • Turbo decoding usually requires long processing delay and is used for delay-tolerant packet data services

  29. Support of 5 ms frames • Shorter frame sizes allows faster signaling between MS and BS • 5ms mini frames can be operated on FCH, DCCH, or some of the common channels such as F-CCCH and R-CCCH • 5ms frames are intended to carry small signaling messages that require a fast turn around time • For example, the mini-PPSMM message, Supplemental Channel Request Mini Message (SCRM), Forward/Reverse Supplemental Channel Assignment Mini Message (SCAM), etc. • The 5ms frame support is optional for MS and BS

  30. Physical Layer Modulation Differences • Forward Link Differences • True QPSK using Complex Spreading on I and Q channel • More robust to mitigate interference • Reverse Link Differences • IS-95 Reverse Link is either Access or Traffic channel • cdma2000 transmits multiple channels simultaneously • Each channel assigned either I or Q path • Each channel can have different rates and power levels • Walsh sequences separate physical channels • Complex Spreading on I and Q channel • No PCG power gating as with IS-95

  31. Agenda • CDMA2000 Protocol Layers • Air Interface Physical Layer • Data Multiplexing • Power Control Enhancements • Rel. C Features

  32. Radio Access Bearer Profile Support • RAB: A service connection with a BS • MAC controls profile of RAB assigned to a single user • MAC also control logical to physical mapping • Even though multiple service options may be connected between the Core Network and the MS, each of them corresponding to a RAB, MAC may still map two or more bearers onto a single physical channel • LPM (Logical to Physical Channel Mapping) • Key for supporting complex services such as Concurrent Services for multimedia applications (e.g. parallel voice and video streams).

  33. RABs supported by CDMA2000 • V1 (Voice Option 1): Signaling and Voice on FCH • V2 (Voice Option 2): Voice on FCH; Signaling on DCCH • P1 (Packet Option 1): Signaling and Data on FCH; Data Bursts on SCH • P2 (Packet Option 2): Signaling and Data on DCCH; Data Bursts on SCH • P3 (Packet Option 3): Data on FCH; Signaling on DCCH; Data Bursts on SCH • VP1 (Voice and Data Option 1): Signaling, Voice, and Data on FCH; Data Burst on SCH • VP2 (Voice and Data Option 2): Signaling and Voice on FCH; Data on DCCH; Data Burst on SCH • CH (Control Hold Mode): Only Reverse Pilot Tx (reduced power) Power Control is on FCH if present, DCCH otherwise

  34. Bearer Profile Support Requirements Requirements: • V1: Mandatory for MS and BS • V2: Optional, but Mandatory if DCCH is supported • P1: Optional, but Mandatory if SCH is supported • P2: Optional, but Mandatory if both DCCH and SCH are supported • VP1: Optional, but Mandatory if SCH is supported and Concurrent Services is supported • P3, VP2: Optional for MS and BS

  35. IS-2000 Data Multiplexing • Traffic Types • Primary Traffic: User Voice • Secondary Traffic: User Data other than Voice • Signaling: Call Control Messaging • Mode A: IS-95 compatible • FCH for signaling and primary and/or secondary traffic • Up to 7 SCCH channels for Medium Data Rate (MDR) • Mode B: cdma2000 enhancement • FCH and/or DCCH for signaling and primary and/or secondary traffic • Up to 2 SCH channels for High Speed Data (HSD) • FCH Dim-and-Burst and Blank-and-Burst • Primary Traffic Only • Dim-and-Burst Rate: 1/2, 1/4, 1/8 division of Primary traffic and Signaling or Secondary traffic • Blank-and-Burst: Signaling Only

  36. IS-2000 Data Multiplexing • Multiplexing: Tx and Rx function routing under QoS priorities • RLP: Radio Link Protocol for segmentation and reassembly of packets (IS-707A)

  37. RLP Types • Type 1: Rate Set 1 (9600 bps) • FCH supports full, 1/2, 1/4, 1/8 rate • DCCH, SCH, SCCH supports full rate • Type 2: Rate Set 2 (14400 bps) • FCH supports full, 1/2, 1/4, 1/8 rate • DCCH, SCH, SCCH supports full rate • Type 3: Used on SCH to select RS, block size, and rate multiplier (19.2 kbps to 230.4 kbps) • Type 4: Used on FCH and DCCH supporting 5ms for signaling • Type 5: Used on SCH, single service data only, variable length • Type 6: Used on FCH and DCCH, multiple services

  38. Logical Transmit Unit (LTU) Processing • LTU: Logical Transmission Unit • Split higher rate frames into sub-frames (LTU) with their own CRCs inserted at the MAC layer. • Physical layer frame is the same regardless of number of LTUs • When LTUs processing is used and the physical frame is received in error, the multiplexing sublayer will perform CRC checking on a per LTU basis and may be able to recover one or more LTUs • More efficient than discarding the entire frame in error

  39. MuxType for RLP Type 3 Data • Service Negotiation between MS and BS results in time limited bandwidth reservation Above tables applies per SCH (0/1)

  40. Agenda • CDMA2000 Protocol Layers • Air Interface Physical Layer • Data Multiplexing • Power Control Enhancements • Rel. C Features

  41. Fast Forward Link Power Control • Major contributor to increased capacity (2x voice capacity) by decreasing the overall interference on the Forward Link • In IS-2000 the forward link dedicated traffic channels (FCH, DCCH, SCH) can be jointly power controlled at a rate of up to 800 Hz • ‘Up’/’Down’ power control bits in 1dB, 0.5dB, or 0.25dB • The power control information bits are carried over the reverse power control subchannel, which is time multiplexed with the Reverse Link Pilot Channel

  42. Fast Forward Link Power Control Modes • Five forward link power control modes in Release 0, plus two more modes added in Release A • Mode 0x00: • The reverse power control subchannel is entirely dedicated to either the forward FCH or DCCH • The power control subchannel rate is in this case equal to 800 Hz • Each traffic channel frame carries 16 power control groups • Mode 0x01 or 0x10: • Two reverse power control subchannels are time multiplexed • The primary subchannel controls either the forward FCH or DCCH, while the secondary subchannel controls the SCH. • Primary and secondary can be both operated at 400 Hz, or can be operated at 200 and 600 Hz, respectively. • Mode 0x11 or 0x100: • The power control subchannel bits are all set equal to the Erasure Indicator Bit (EIB) or the Quality Indicator Bit (QIB), therefore slowing down the effective rate of the power control subchannel to 50 Hz. • Mode 0x11: Equivalent to the power control method used in IS-95B Rate Set 2 transmission

  43. Fast Forward Link Power Control Modes • Mode ‘101’ (Rel A): • MS uses the QIB definition with 800 bps feedback on the Reverse Power Control Subchannel are grouped into 50, 25, or 12.5 bps depending on the frame length of that F-SCH. • Mode ‘110’ (Rel A): • MS maintains a 400 bps feedback on the F-FCH or the F-DCCH (similar to FPC_MODE = ‘001’) • Remaining 400 bps are grouped into 50, 25, or 12.5 bps feedback to send the EIB (similar to FPC_MODE = ‘011’) on the master F-SCH • The BS gains much faster feedback on the true quality of the F-SCH without incurring much signaling load

  44. Enhanced Reverse Link Open Loop Power Control • IS-95B uses fixed power estimate parameters for R-FCH • IS-2000: the R-PICH open loop power control is specified, and each code channel output power for the reverse traffic channels are set relative to the pilot channel • BS controls power levels on per call basis • Allows the most reliable call setup balanced with reverse link network capacity

  45. Agenda • CDMA2000 Protocol Layers • Air Interface Physical Layer • RLP Type 3 and Multiplex Options • Power Control Enhancements • Rel. C Features

  46. Fundamentals of EV-DV • 1x Evolution to Data and Voice (1xEV-DV) • Single 1.25 MHz bandwidth shared between voice and data users • 3.1 Mbps peak data rate on Forward Packet Data Channel (F-PDCH) • Voice users are usually scheduled first • Dynamic allocation of the unused BS power to data users every slot cycle (1.25 ms)

  47. Some Details • EV-DV scheduler controls the allocation of Walsh space and BS power based on user traffic type (voice, ftp, http, etc.), buffer size and channel conditions • MS monitors and reports its channel condition (C/I) every 1.25 ms

  48. Major Feature Enhancements • 3.1 Mbps data rate on Forward Packet Data Channel (F-PDCH) • Two Forward Packet Data Control Channels (F-PDCC0/1) to support F-PDCH operations • Two Reverse Control Channels (R-CQICH and R-ACKCH) to provide scheduler feedback • Adaptive Modulation and Coding (AMC) • BS rate control based on MS channel conditions • Hybrid ARQ using Autonomous Adaptive Incremental Redundancy (AAIR)

  49. Dynamic Link Adaptation • Variable parameters = transmit power, modulation, code rate, packet length (1, 2, 4 slots), Walsh space • BS receives C/I values from each MS • Uses C/I and current BS load to decide transmit parameters • If mobile is able to successfully decode the PDCH it sends an ACK on the ACK channel • If NAK sent, packet will be re-transmitted using HARQ* (AAIR - Autonomous Adaptive Incremental Redundancy) • Up to 4 HARQ channels in parallel to reduce latency • HARQ combines information from previous transmission (not a simple re-transmission) * Hybrid Automatic Retransmission and Queing

  50. EV-DV Link Adaptation

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