1 / 14

SMART ANTENNAS FOR TDMA

SMART ANTENNAS FOR TDMA. Jack H. Winters. AT&T Labs - Research Red Bank, NJ 07701-7033 jhw@research.att.com September 7, 2000. Uplink Adaptive Antenna. SIGNAL. SIGNAL OUTPUT. INTERFERENCE. BEAMFORMER WEIGHTS. BEAM SELECT. SIGNAL. BEAMFORMER. INTERFERENCE. Smart Antennas for TDMA.

zareh
Download Presentation

SMART ANTENNAS FOR TDMA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. SMART ANTENNAS FOR TDMA Jack H. Winters AT&T Labs - Research Red Bank, NJ 07701-7033 jhw@research.att.com September 7, 2000

  2. Uplink Adaptive Antenna SIGNAL SIGNAL OUTPUT INTERFERENCE BEAMFORMER WEIGHTS BEAM SELECT SIGNAL BEAMFORMER INTERFERENCE Smart Antennas for TDMA • Key enhancement technique to improve system capacity and user experience • Leverage Smart Antennas currently in development/deployment for IS-136 TDMA Downlink Switched Beam Antenna SIGNAL OUTPUT Aggressive frequency re-use(7/21,4/12,1/3) High spectrum efficiency  Increased co-channel interference Smart antennas provide substantial interference suppression for enhanced performance

  3. Smart Antennas 11.3 ft Prototype Dual Antenna Handset Rooftop Base Station Antennas Prototype Smart Antenna for Laptops

  4. SMART ANTENNAS IN SECOND GENERATION SYSTEMS • IS-136 TDMA: • On uplink, with two receive antennas, in 1999 changed from maximal ratio combining to optimum combining • Software change only - provided 3-4 dB gain in interference-limited environments • Combined with power control on downlink (software change only) - increased capacity through frequency reuse reduction • Use of 4 antennas (adaptive array uplink/multibeam, with power control, downlink) extends range and/or doubles capacity (N=7 to 4 or 3) • Clears spectrum for EDGE deployment (2002) • Limited deployment at base stations

  5. RADIO UNIT ADAPTIVE ANTENNA RECEIVER 4 Branches RSSI, BER Shared LPAs Power Control DUPLEXERS Atten SPLITTER TRANSMITTER Atten Atten Atten BEAM SCANNING RECEIVER 1 per N radios • IS-136 Smart Antenna System • 4 Branch adaptive antenna uplink for range extension and interference suppression • Fixed switched beam downlink with power control for increased coverage and capacity • Uplink and downlink are independent • Shared linear power amplifiers reduce amplifier requirements to handle maximum traffic load

  6. Smart Antenna System • Dual-polarized slant 45° PCS antennas separated by10 feet and fixed multibeam antenna with 4 - 30° beams • 4 coherent 1900 MHz receivers with real-time baseband processing using 4 TI TMS320C40 DSPs

  7. INTERFERENCE SUPPRESSION - OFFSET INTERFERER 0 -0.5 -1 -1.5 -2 -2.5 -3 -3.5 -4 10 20 30 0 Spatial Diversity: S/I = 0dB, AAA with 4 antennas vs. REF with 2 antennas • AAA(avg.) • REF (avg.) • AAA (data) • REF (data) BER SNR (dB)

  8. ADAPTIVE ARRAYS IN EDGE Spatial-Temporal processing using DDFSE for interference suppression

  9. ADAPTIVE ARRAYS IN EDGE

  10. EDGE with Interference Suppression in a Typical Urban Environment Rx DDFSE Equalizer Channel Decoder Output Data Rx Block Error Rate Signal -to-Interference Ratio (dB) Wireless Systems Research Dual Diversity Receiver Using Delayed Decision Feedback Sequence Estimator for Joint Intersymbol Interference and Co-channel Interference Suppression EDGE Smart Antenna Processing • Simulation results show a 15 to 30 dB improvement in S/I with 2 receive antennas • Real-time EDGE Test Bed supports laboratory and field link level tests to demonstrate improved performance

  11. MIMO-EDGE • Goal: 4 transmit / 4 receive antennas in EDGE can theoretically increase capacity 4-fold with the same total transmit power (3.77X384 kbps = 1.45 Mbps is actual theoretical increase) • Issues: • Joint spatial-temporal equalization • Weight adaptation • Mobile channel characteristics to support MIMO-EDGE • Our approach: • Development of multi-antenna EDGE testbed • Development of 2X2 and 4X4 DDFSE architecture with MMSE combining using successive interference cancellation • Mobile channel measurements

  12. EDGE with Wideband OFDM - MIMO Downlink • High data rates (>1 Mbps) required on downlink only • OFDM eliminates need for temporal processing => simplified MIMO processing for much higher data rates • With 1.25 MHz bandwidth, QPSK, OFDM-MIMO with 4 antennas at base station and terminal => 10 Mbps downlink

  13. SMART ANTENNA EVOLUTION • IS-136: • Optimum combining uplink / power control downlink at all base stations with existing 2Rx/1Tx antennas • 4Rx/4Tx antenna upgrade (adaptive uplink/multibeam downlink) for N=7 to 4 to clear spectrum for EDGE • EDGE: • S-T processing with IS-136 smart antennas (Data followed by VoIP) • MIMO-EDGE (1.5 –2.4 Mbps) • Wideband OFDM-MIMO downlink (10-40 Mbps)

More Related