Multiplexing and multiple accessing are similar concepts that provide solutions for complex electronic communication. While multiplexing involves transmitting multiple signals and streams simultaneously, multiple accessing is shared access of resources by multiple users in different geographical locations. Multiple accessing is based on schemes such as frequency division, time division or code division.
Frequency Division Multiplexing
Frequency-division multiplexing is a system that divides carrier bandwidth into sub channels. Analog transmission is delivered with this method. Carrier bandwidth makes up the wireless channels that deliver signals by simulating frequencies of the electromagnetic spectrum. Carrier service providers such as Zayo Group offer high bandwidth solutions for delivering multimedia.
Time Division Multiplexing
Time-division multiplexing delivers multiple signals sent over one channel over different time slots. Digital transmission uses this method. A high capacity communications channel such as a T1 line bundles 24 channels and delivers 8,000 readings per second, which defines the time slot. Time-division multiplexing is useful when existing multiple channels are already available.
Code Division Multiplexing
Code division multiplexing delivers signals from different sources simultaneously over the same channel. Orthogonal codes, which are independent of the information being sent, are used to spread the signal over wide bandwidth. This transmission technique is known as spread spectrum, which is used to improve reliability and security in wireless transmission.
A wireless communication system using multiple inputs and outputs to transmit multiple signals is a model for spectral efficiency in a point-to-point network. Modern wireless systems are designed to reduce the deficiencies of multipath,fading, which is signal loss due to obstructions in line of sight transmission. Power line communication is a robust alternative multiple accessing scheme but presents unfavorable conditions such as heavy load, noise and interference.
- Search Networking: Multiplexing
- Rice University: A Comparative Study of Multiple Accessing Schemes
- AccessScience: Multiplexing and multiple access
- Zayo Group: Carrier Bandwidth Infrastructure Solutions
- National Instruments: Theory of Time Division Multiplexing
- National Instruments: Theory of Code Division Multiplexing
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