BEYOND OFDM A Systems Approach to Non-Line-of-Sight Fixed Wireless Rajeev Krishnamoorthy Broadband World Wireless Forum, San Francisco, CA February 19, 2001

BEYOND OFDM - A Systems Approach to NLOS Fixed Wireless Rajeev Krishnamoorthy, Senior Engineering Director, Iospan Wireless / Slide 2 Broadband World Wireless Forum - San Francisco, CA - February 19, 2001 Broadband Market Requirements  A Mass-Deployable system with a price point that will compete favorably to DSL and Cable:  Low Capital Costs for Installed CPE & Infrastructure  DSL/Cable-like QoS/Availability  Easy Management/Provisioning These features require:  True Non-Line-of-Sight Coverage  Multi-cell with largest possible radius (6-miles or greater) and superior frequency reuse (scalable)  Consumer installable CPE  Can re-use existing cellular sites  Minimum of 90% service coverage (homes passed)

BEYOND OFDM - A Systems Approach to NLOS Fixed Wireless Rajeev Krishnamoorthy, Senior Engineering Director, Iospan Wireless / Slide 3 Broadband World Wireless Forum - San Francisco, CA - February 19, 2001 Fading Frequency Selective -- OFDM Space Selective -- MIMO + MAC Time Selective -- Link Adaptation + RLP Channel Impairments in Multi-Cell Co-channel Interference time  frequency  space  C I

BEYOND OFDM - A Systems Approach to NLOS Fixed Wireless Rajeev Krishnamoorthy, Senior Engineering Director, Iospan Wireless / Slide 4 Broadband World Wireless Forum - San Francisco, CA - February 19, 2001 Physical Layer Characteristics  Multicarrier (OFDM) Modulation Important Foundation, but OFDM ALONE IS NOT ENOUGH TO ACHIEVE NLOS!  MIMO (Multiple Input, Multiple Output) – Dynamic Per-user Spatial Processing Techniques  Antenna Diversity Techniques to Increase Cell Size and Provide Complete Service Coverage  Spatial Multiplexing: Increased Bit Rate to Users  Aggressive Spectrum Reuse due to Interference Cancellation  Dynamic Per-user Adaptive Modulation and Coding ( Link Adaptation)  Delivers Optimal System Capacity by:  Exploiting good conditions to increase user data rates  Accommodating poor air-link conditions  Done in conjunction with QoS Requirement & MAC Scheduling

BEYOND OFDM - A Systems Approach to NLOS Fixed Wireless Rajeev Krishnamoorthy, Senior Engineering Director, Iospan Wireless / Slide 5 Broadband World Wireless Forum - San Francisco, CA - February 19, 2001 MAC Characteristics  Differentiated Grades of Service & Quality of Service  Reservation Schemes for Low Delay Jitter Services  Dynamic Bandwidth Allocation & Scheduling for Bursty Data  Fragmentation & Reassembly and Link-Layer Retransmission  Increases Link Integrity and Improves TCP Performance  Better Frequency Reuse  Support for Unique PHY Modes of Operation  Spatial Multiplexing and Transmit Diversity  Adaptive Modulation and Coding  Power Control  Uplink & Downlink Transmission Scheduling  Support for multiple Service Flows (distinct QoS) on each link  Service Flow Attributes - Class of Service, Bandwidth, Loss, Latency  Other Important Functions  Admission Control, Link Initialization & Maintenance, Authentication & Security, etc.

BEYOND OFDM - A Systems Approach to NLOS Fixed Wireless Rajeev Krishnamoorthy, Senior Engineering Director, Iospan Wireless / Slide 6 Broadband World Wireless Forum - San Francisco, CA - February 19, 2001 Fundamental System Design Requirements  Low-cost RF enabled by digital pre-distortion, increased phase noise tolerance, carrier tracking loops, dynamic link adaptation, etc.  Low-cost mechanical design of CPE by monitoring heat dissipation, antenna design, etc.  QoS jointly guaranteed by the MAC and dynamic link adaptation  High throughput by adaptive techniques, and by ensuring TCP behavior is matched to MAC and Radio Link Protocol  Link optimization by matching QoS (error rate and latency) with the scheduling, ARQ, adaptive modulation, coding, and diversity  Low required SINR (modem set-point) results in greater coverage, higher capacity, lower PA cost, and aggressive frequency reuse A high-performance and low-cost system requires an integrated design encompassing Antennas, RF, PHY, MAC, mechanicals, the network layer, and applications

Supporting Slides

BEYOND OFDM - A Systems Approach to NLOS Fixed Wireless Rajeev Krishnamoorthy, Senior Engineering Director, Iospan Wireless / Slide 8 Broadband World Wireless Forum - San Francisco, CA - February 19, 2001 Diversity using antennas Demonstrating Performance SISO 1  1SIMO 1  2MIMO 2  3 Tx Rx Tx Rx Tx Rx Trials Early Deployment Mass Deployment

BEYOND OFDM - A Systems Approach to NLOS Fixed Wireless Rajeev Krishnamoorthy, Senior Engineering Director, Iospan Wireless / Slide 9 Broadband World Wireless Forum - San Francisco, CA - February 19, 2001 Features & Benefits of Iospan Approach

BEYOND OFDM - A Systems Approach to NLOS Fixed Wireless Rajeev Krishnamoorthy, Senior Engineering Director, Iospan Wireless / Slide 10 Broadband World Wireless Forum - San Francisco, CA - February 19, 2001 The Iospan Advantage