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Examples of channel access methods:

• Frequency division multiple access (FDMA)
• Time-division multiple access (TDMA)
• Code division multiple access (CDMA)
• Frequency-hopping spread spectrum (FHSS)
• Space division multiple access (SDMA)
• Wavelength division multiple access (WDMA)
• Carrier sense multiple access with collision detection (CSMA/CD)

In the OSI seven layer model, channel access methods are typically placed at layer 1, the physical layer.

Where these methods are used for dividing forward and reverse communication channels, they are known as duplexing methods, such as:

• Time division duplex (TDD)
• Frequency division duplex (FDD)

Note that hybrids of these techniques can be and frequently are used: for example, GSM combines the use of frequency division duplex to prevent interference between outward and return signals, with TDMA to allow multiple handsets to work in a single cell.

See also:

• modulationFor the musical use of "modulation", see modulation (music . Modulation describes a range of techniques for encoding information on a carrier signal typically a sine-wave signal. A device that performs modulation is known as a modulator . Modulation techn
• spread spectrumSpread-spectrum telecommunications is a technique in which a signal is transmitted in a bandwidth considerably greater than the frequency content of the original information. Note Frequency hopping, direct sequence, PN spreading, time scrambling, chirp, a
• EthernetEthernet is a packet-based computer networking technology for local area networks (LANs). It defines wiring and signaling for the physical layer, and packet formats and protocols for the media access control (MAC)/ data link layer of the OSI model. Ethern