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Multiple Sensor Communications MIMO. MESA Meeting. O ur proposal. Provide a low cost system with the necessary throughput Rely on existing standards Increase the system capacity with limited system impact Specialise an existing system to fulfil the MESA like system requirements
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Multiple Sensor Communications MIMO MESA Meeting
Our proposal • Provide a low cost system with the necessary throughput • Rely on existing standards • Increase the system capacity with limited system impact • Specialise an existing system to fulfil the MESA like system requirements • MESA wireless system should cope with many transmissions scenarios • Large-short coverage • Indoor and out door • We propose to adapt the 802.16 standard • Increase rate with • Limit the system impact at the access point
MESA transmission context • Provide high data rate transmission • Many propagation scenarios • Indoor • Indoor to outdoor • Outdoor • Privilege the uplink • Changes form the mass market considerations • Coverage • Form 100 m to few Km • Central access point
Different MIMO contexts • Diversity coding & point to point multiplexing • Pros • Full diversity codes exist (for codes) • Rate increase • No synchronisation issues • Cons • No benefit when no diversity (few scatters) • Large existing standard modifications • Where to put the antennas • Multi-user transmissions (multi-point to point) • Pros • Capacity increase • Terminals can be standard (ex: low cost 802.16) • Complexity at the access point • Works even with no scatters (SDMA like) • Cons • System synchronisation between the transmitters • Exists in TDMA/TDD systems
Operational contexts : Spatial diversity The technique should be adapted to the environment • No scatters + SDMA well suited + Multiplexing (multi-point to point) - Multiplexing (point to point) - Diversity coding • Channel with few scatters + Multiplexing (multi-point to point) Diversity coding Multiplexing (point to point) - SDMA • Channel with many scatters + Multiplexing (multi-point to point) + Diversity coding + Multiplexing (point to point) - SDMA
Sub optimal MMSE : Rayleigh Channel • Normalizing the transmitting power (P constant nb Tx) For a given power the system capacity is increased. Identical performance are achieved compared to the SISO system with a sub-optimal low cost receiver Further improvements in range/robustness/coverage are achievable with a little more complexity in the receiver P P/3 P/3 P/3 P/4 P/4 P/4 P/4 Eb/No for one user
Conclusions • The simultaneous multiple user transmission technique seem the better adapted to increase the capacity of existing standards (802.16) • Provides enhancements in all transmission scenarios • MESA mainly outdoor or indoor to outdoor • Provides large systems improvements with minor changes to existing standards • The terminals need a minor layer 1 and 2 modification • Privileges the uplink • The complexity is deported to the access point • Low cost terminals allow larger access to the system