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The paper presents a testbed for Wireless Sensor Networks (WSN) located at Universidad del Norte in Barranquilla Colombia, created for testing different communication protocols in a real scenario with non-line of sight (NLOS) links and interference. The testbed uses XTend RF Modules at 900MHz, with 1 mW transmission power, and covers an area of 11,000 m2. Results show that the testbed has propagation...
We consider a cooperative overlay cognitive network, where the secondary exploits the primary retransmissions. We show that by using cooperation, the secondary rate can be considerably increased when compared to other schemes, without causing major impact on the primary performance. The best configuration for the proposed scheme is that in which the secondary nodes are close to the primary transmitter.
The emerging IEEE 802.11ac standard introduces spatial division multiplexing access, in its downlink version, to the wireless local access world. Through this multi-user multiple input multiple output (MU-MIMO) technique the access point (AP) can simultaneously transmit multiple independent groups of streams to different stations. The consequent precoding requires precise channel knowledge and thus...
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