Multiple Sensor Communications MIMO
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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
Multiple Sensor Communications MIMO
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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