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HIGH CAPACITY ADAPTIVE BASE-STATION ANTENNA SYSTEMS · PDF file WCDMA (Wideband Code Division Multiple Access) • Hardware realization • Conclusions. Ericsson Research ISART´02,

Feb 02, 2021

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  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    HIGH CAPACITY ADAPTIVE BASE-STATION ANTENNA SYSTEMS

    Anders G Derneryd

    Ericsson AB Antenna Research Center

    SE-431 84 Molndal, Sweden

    Email: [email protected]

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    Outline

    • Background • Adaptive Antenna Systems

    GSM (Global Systems for Mobile Communications) GPRS (General Packet Radio Service)

    EDGE ( (Enhanced Data Rates for Global Evolution) WCDMA (Wideband Code Division Multiple Access)

    • Hardware realization • Conclusions

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    Background

    Growth from previous year

    • Increased mobile subscribers growth

    • To satisfy capacity demand, new technology is needed

    • Conventional ways to increase capacity

    ½ More radio spectrum: Regulatory limitations and high costs ! New terminals !

    ½ Cell splitting: High costs of acquring new sites & infastructure !

    ½ Higher degree of sectorization: Increased number of hand-offs !

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    Technology for Advanced Antenna Systems

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    Basic three-sector sites

    Higher order sectorization

    Fixed multi-beam antenna

    Steered beam antenna

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    GSM Adaptive Antenna Concept

    Array antenna

    Interferer

    Interferer

    Desired

    • Narrow beams are directed from the base-station towards the mobile stations

    • A beam can be (steered towards the desired mobile station or) selected from a set of fixed beams

    • The beam for downlink transmission is determined on information derived from the uplink, the direction of arrival (DOA)

    Adaptive Antenna System

    Reduced Interference

    Tight Frequency Reuse Possible

    Large Capacity Increase

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    GSM Multi-Beam Adaptive Antenna System

    Ericsson implementation

    • Low complexity adaptive antenna system solution

    • Non-coherent radio chains

    • 8 fixed narrow interleaved beams per 120° sector

    • RF level beamforming, with no calibration requirement

    • Best beams selected for uplink combining

    • Best beam selected for downlink transmission

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    GSM Capacity Booster, RBS 2205

    Radio base-station 8-beam array antenna

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    Capacity Increase with GSM Adaptive Antenna

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    0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32

    Adaptive Ant. Sol. cells introduced in network [% of total number of cells]

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    Adative antenna systems introduced in network (% of total number of cells)

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    GSM Adaptive Antenna Characteristics

    • Tailored antenna beams reduce interference levels and enable a tighter frequency reuse pattern

    • Live field trials show a capacity increase of more than 100% at sites using GSM adaptive antennas

    • Substantial network capacity increase can be achieved by introducing adaptive antennas in only a limited number of sites

    Goal: Reduce Operator Infrastructure Cost

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

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    EDGE EDGE IntroducesIntroduces a Newa New Modulation Modulation

    GPRS: GMSK Modulation

    EDGE: 8PSK Modulation

    1 bit per symbol 3 bits per symbol

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    Basic Technical Parameters

    GPRS EDGE

    Modulation GMSK 8-PSK

    Symbol rate 270 ksym/s 270 ksym/s

    Modulation bit rate 270 kb/s 810 kb/s

    Radio data rate per time slot 22.8 kb/s 69.2 kb/s

    User data rate per time slot 20 kb/s 59.2 kb/s

    User data rate @ 8 time slots 160 kb/s 473.6 kb/s

    (including header bits) (182.4 kb/s1)) (553.6 kb/s1))

    1) Usually specifed at 115 kbps and 384 kbps, respectively.

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    C/I Simulation Results for EDGE

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    C/I [dB]

    Sec, 35 users Sec, 50 users AA, 35 users AA, 50 users AA, 65 users

    • www-traffic model

    • Link-adaptation inactive

    • Same amount of traffic

    • No protocol aspects considered

    15 dB

    C/I (dB)

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  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    9.6 - 14.4 kb/s

    57.6 kb/s

    115 kb/s

    384 kb/s

    GPRS

    HSCSD

    EDGE

    CS

    • No new license required

    • Short time to market

    • Low investment costs

    • Capacity tripled

    • Data rates tripled

    EDGE Achievements

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    Interference Environments, TDMA vs CDMA

    • TDMA - Inter cell interference

    (co-channels in distinct reuse pattern directions)

    • CDMA - Intra cell interference - Inter cell interference

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    WCDMA Downlink C/I Simulation

    C/I (dB)

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  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    Cylindrical vs. Planar Multi-Beam Antennas

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  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    Cylindrical Array Antenna Example

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    Cylindrical Omni-Directional Array Antenna

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    l 12 radiating columns

    l 2 wavelength diameter

    l 0.5 wavelength spacing

    l all columns fed

    l in-phase excitation

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    Cylindrical Multi-Beam Array Antenna

    l 12 radiating columns

    l 2 wavelength diameter

    l 0.5 wavelength spacing

    l 5 fed columns

    l co-phasal excitation

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  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    Cylindrical Array Antenna Trade-Offs

    l Radiation pattern types – Omni-directional beam for coverage and/or broadcast – Narrow multi-beams for capacity

    l Cylinder radius and number of radiating elements – Radiation pattern ripple in azimuth with omni coverage – Number of directional beams in azimuth for capacity – Sidelobe level

  • Ericsson Research ©2002 Ericsson ABISART´02, 4-6 March 2002, A Derneryd

    Adaptive Base-Station Antenna System Conclusions

    l Less interference transmitted – Minimize interference spread in downlink

    l Enable receiver interference suppression – Possibility to utilize spatial separation in uplink

    l Adaptive antenna systems show substantial performance improvements

    l Grow-on-site capacity increase in existing networks – No new additional sites – Site-by-site migration strategy

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