Technical Approaches for 3GPP2 Evolution Dr. Byung K Yi Chair, TSG-C LG Electronics

1 Executive Summary Background Evolution Phase 1 Evolution Phase 2 Multiple Antenna Technologies Spectral Efficiency –Spatial Processing –Interference Reduction Other Features Summarizing Remarks Outline

2 Significant support has been expressed for cdma2000 evolution Air Interface Evolution Technical Experts Meeting (AIE TEM) for 3GPP2 Evolution was held during March, 2005 in Denver, CO, USA. AIE TEM workshop was intended to share the views of the future 3GPP2 evolution. 10 requirement and 11 technical contributions were presented. Phased approaches for evolution were proposed and discussed. This presentation summarizes proposed technical solutions for phased evolution. Executive Summary

3 Proposed specifications for future wireless cellular systems included: –Increased spectral efficiency e.g.,  4 bps/Hz –Higher peak data rates and system capacity Long-term targets for peak data rate –FL: 100 Mbps ~ 1 Gbps –RL: 50 ~ 100 Mbps Background

4 N x cdma2000: Phase I –Maximize Return on Investment (ROI) by maintaining backward compatibility for short-term –Fast time-to-market to maintain a market leadership –Number of 1.25 MHz carriers, N, 15  N  1 –Both symmetric and asymmetric FL/RL assignments Minimum N = 1 for backward compatibility Multi-carrier cdma2000 (1/4)

5 Symmetric and asymmetric carrier assignments. Example of asymmetric assignment is FTP download. Multi-carrier cdma2000 (2/4)

6 N x cdma2000: Phase II Enhancements of existing Multi-carrier cdma2000: –Backward compatibility –Rapid time-to-market for broadband services –Technologies under consideration: Interference Cancellation Enhanced FL Equalizer Advanced FEC Antenna Techniques Multi-carrier cdma2000 (3/4)

7 Coexistence of new modulation over existing multi- carrier HRPD: –Providing improved spectrum utilization and peak data rates while maintaining backward compatibility –New modulation: OFDM –OFDM symbols in cdma2000 slots –Advanced Technologies: MIMO SDMA Multi-carrier cdma2000 (4/4)

8 Example: 1xEV-DO, NxEV-DO, and broadband OFDM coexist in the same N = 3 carriers. Multi-carrier EV-DO

9 Bandwidth up to 20 MHz or more Peak data rates –FL: 100 Mbps ~ 1 Gbps –RL: 50 Mbps ~ 100 Mbps Criteria for new air interface –Ease of scalable bandwidth operation –Excellent performance in frequency-selective channels in broadband –Reduced handset complexities –Easy accommodation of advanced technologies New Air Interface

10 OFDM –Bandwidth scalability with orthogonal frequency separation –Full utilization of frequency selectiveness –High performance in a multipath channel –Narrow sidelobes MC-CDMA –CDMA + OFDM DS-CDMA with higher chip rate Single carrier with cyclic prefix and frequency domain equalizer –Comparable performance to OFDM –Reduced peak-to-average power ratio (PAPR) Possible Candidate Multiplexing Technologies

11 Graphical representation of OFDM in time and frequency domain OFDM

12 Example: OFDM + CDMA –One time slot (2048 chips) is divided into 4 OFDM-CDMA symbols –One carrier has 512 tones –Each chip is mapped to one tone OFDM + CDMA

13 Use of multiple antennas at the transmitter and receiver –Improves SNR through beamforming array gain –Reduces CCI or MAI Improves coverage, capacity, and data rate –Enhances spatial diversity Improves signal quality –Increases spectral efficiency by means of spatial multiplexing Spatial Processing –Spatial multiplexing –Space Time Codes (STC) –Beamforming –SDMA Multiple Antenna Technologies (1/2)

14 Multiple antennas at both the transmitter and receiver is a key technology for broadband wireless communications. Multiple Antenna Technologies (2/2)

15 To achieve higher data rate and reduced cost per bit, higher spectral efficiency is required Spatial signal processing has opened another domain in addition to time and frequency domain to provide higher spectral efficiency  Space Domain. In cellular environments, inter-cell interference is a major hurdle for higher spectral efficiency. Spectral Efficiency

16 Exploiting the spatial dimension in signal processing for cellular communication networks to improve: –Coverage –Signal Quality –Spectral Efficiency Higher spectral efficiency comes by means of spatial multiplexing. –Multiple spatial data pipes between TX and RX Spatial Processing (1/3)

17 SDMA with fixed beams –Low complexity  Beam selection only –Example below shows maximum 6 times bandwidth reuse using overlapped 12 beams (12 antennas) Spatial Processing (2/3) Directional Gain [dB] Angle [degree] #a #b#c#d#e#f #g #h#i#j#k#l Beam IDs

18 Spatial Multiplexing (SM) Technologies –Multiple antenna technique for achieving higher data rate efficiently –Independent data streams transmitted on each antenna –Requires multiple receive antennas and sophisticated SM receiver processing –Works best in scattering channels Spatial Processing (3/3)

19 BS cooperation approach to reduce inter-cell interference: Each MS measures and reports which beam cause inter-cell interference. BSs make schedules in cooperation to avoid beam collision. Advanced Signal Processing Techniques –Enhanced forward link equalizer –Interference Cancellation –MUD Interference Reduction BS1 BS2 Receive data from BS2-beam3 without interference Receive data from BS1-beam4 without interference Interference due to beam collision Exchange beam schedule MS1 MS2 MS3

20 Additional improvements to broadcast and multicast services (BCMCS) –Cellular Digital Multimedia Broadcast (CDMB) Compatible with 1x and Nx CMDA channels Other Features

21 Common Objectives for 3GPP2 Evolution –Increase data rate to maintain a market leadership over other wideband systems –Latency reduction –Backward compatibility for near-term Two-step phased approaches for evolution were proposed to leverage investments while exploiting the promising technologies for each phase. Summarizing Remarks (1/3)

22 Summarizing Remarks (2/3) Phase I –Cost effective and straightforward migration to provide higher transmission rates and spectral efficiency –Nx CDMA systems –Peak data rates: FL Peak Data Rate: at least 3 x HRPD Rev A FL (3.01 Mbps) up to 50 Mbps RL Peak Data Rate: at least 3 x HRPD Rev A RL (1.8 Mbps) up to 29 Mbps

23 Phase II –Further enhancements beyond Phase I by providing higher data rates and spectral efficiency –Peak data rates greater than 100 Mbps –Candidate Technologies: CDMA with Equalizer or Interference Cancellation OFDM(A) IFDMA MIMO, SDMA Advanced Modulation and Coding Summarizing Remarks (3/3)

24 All AIE TEM presentations may be found at: –ftp://ftp.3gpp2.org/Work_Shops/AIE_TEM Denver/ References cdma2000 ® is the trademark for the technical nomenclature for certain specifications and standards of the Organizational Partners (OPs) of 3GPP2. Geographically (and as of the date of publication), cdma2000 ® is a registered trademark of the Telecommunications Industry Association (TIA-USA) in the United States.

25 7. C00AIE AR1, “ HRPD Evolution Technology Enhancements ”, Lucent, March C00AIE , “ Motorola ’ s View on cdma2000 Air Interface Evolution ”, Motorola, March C00AIE , “ A Look at Evolving cdma2000 Technical Approaches ”, Nokia, March C00AIE , “ 3GPP2 Air Interface Evolution ”, Nortel, March C00AIE R1, “ cdma2000 Evolution Technical Summary ”, Qualcomm, March C00AIE R1, “ Key Technologies for cdma2000 Evolution ”, Samsung, March C00AIE , “ CDMB-Cellular Digital Multimedia Broadcast ”, Via Telecom, March 2005 Technical Contributions (2/2)