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Wireless Multiple Access Multiple Simultaneous Connections By Dr. Larry Hash.

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Presentation on theme: "Wireless Multiple Access Multiple Simultaneous Connections By Dr. Larry Hash."— Presentation transcript:

1 Wireless Multiple Access Multiple Simultaneous Connections By Dr. Larry Hash

2 Multiplexing Multiple information streams combined FDM Separate frequency for each user For example - cable TV TDM Separate time slot for each user For example – T1 Synchronization is controlled at a single point for both downlink and uplink

3 Multiple Access Similar to Multiplexing except Each uplink transmission comes from an independent transmitter Uplink synchronization control is distributed Types FDMA – Frequency Division Multiple Access For Example - Analog cell phones TDMA – Time Division Multiple Access For Example – GSM cell phones CDMA – Code Division Multiple Access For Example – 3 rd Generation cell phones

4 FDMA Separate frequency for each user Uplink transmitter controls Frequency agile Frequency control Bit sync

5 TDMA Separate time slot for each user Uplink transmitter controls Time slot timing Propagation time compensation Bit sync

6 CDMA Separate code for each user Uplink transmitter controls Power control Bit sync

7 Duplexing The reverse channel Mobile to Base FDD – Frequency Division Duplexing Reverse channel is assigned a separate frequency Separation from forward channel TDD – Time Division Duplexing Reverse channel is assigned a separate time slot CDD – Code Division Duplexing Reverse channel is assigned a separate code


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