Avancerad sökning
Hittade 4 avhandlingar som matchar ovanstående sökkriterier.
1. Superimposed codes for additive channels
Sammanfattning : We consider a situation where several users send information over a single additive channel. We suppose the transmission is synchronized and that at most m of the total number of potential T users transmit simultaneously. The receiver gets a message which is the sum of the messages of the active users at that moment. LÄS MER
2. Spectrum Sensing Algorithms Based on Second-Order Statistics
Sammanfattning : Cognitive radio is a new concept of reusing spectrum in an opportunistic manner. Cognitive radio is motivated by recent measurements of spectrum utilization, showing unused resources in frequency, time and space. Introducing cognitive radios in a primary network inevitably creates increased interference to the primary users. LÄS MER
3. Improving the Efficiency of Control Signaling in Wireless Multiple Access Systems
Sammanfattning : Prior to the transmission of payload data in any multiple access system, there is generally a need to send control information such as scheduling assignments, transmission parameters and HARQ acknowledgments. This process is called control signaling and has a significant impact on the overall system performance. LÄS MER
4. HARQ Systems: Resource Allocation, Feedback Error Protection, and Bits-to-Symbol Mappings
Sammanfattning : Reliability of data transmission is a fundamental problem in wireless communications. Fading in wireless channels causes the signal strength to vary at the receiver and this results in loss of data packets. To improve the reliability, automatic repeat request (ARQ) schemes were introduced. LÄS MER