spread-spectrum multiple access
Quick Summary
Spread-spectrum multiple access (SSMA), also known as code-division multiple access (CDMA), is a method for sharing a communications channel among multiple users. In CDMA, signals are transmitted simultaneously within the same frequency band. Each user is assigned a unique signature waveform, generated by a spreading code, which allows the receiver to distinguish and select specific signals while rejecting others.1
This technique is used in advanced mobile cellular systems. The process involves multiplying the signal by a code sequence, which spreads the signal's power over a larger bandwidth. This eliminates the need for frequency management, allowing new users to transmit immediately upon being assigned a code, rather than waiting for an available frequency slot.1
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telecommunicationCode-division multiple access…is sometimes referred to as spread-spectrum multiple access (SSMA), because the process of multiplying the signal by the code sequence causes the power of the transmitted signal to be spread over a larger bandwidth. Frequency management, a necessary feature of FDMA, is eliminated in CDMA. When another user wishes to…
Read More…is sometimes referred to as spread-spectrum multiple access (SSMA), because the process of multiplying the signal by the code sequence causes the power of the transmitted signal to be spread over a larger bandwidth. Frequency management, a necessary feature of FDMA, is eliminated in CDMA. When another user wishes to…
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telecommunications networkSpread-spectrum multiple accessSince collisions are so detrimental to network performance, methods have been developed to allow multiple transmissions on a broadcast network without necessarily causing mutual packet destruction. One of the most successful is called spread-spectrum multiple access (SSMA). In SSMA simultaneous transmissions will…
Read MoreSince collisions are so detrimental to network performance, methods have been developed to allow multiple transmissions on a broadcast network without necessarily causing mutual packet destruction. One of the most successful is called spread-spectrum multiple access (SSMA). In SSMA simultaneous transmissions will…
Read More