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Elimination yield –Non Pre-emptive Multiple ACCESS (EY-NMPA) is a SCHEME which uses several phases to SENSE the medium. Access the medium and for contention RESOLUTION... PRIORITY schemes can also be included. This is actually used in HIPERLAN1 specification.

Elimination yield –Non Pre-emptive Multiple Access (EY-NMPA) is a scheme which uses several phases to sense the medium. Access the medium and for contention resolution... Priority schemes can also be included. This is actually used in HIPERLAN1 specification.

Logical LINK Control(LLC)
MEDIA ACCESS Control(MAC)

Logical Link Control(LLC)
Media Access Control(MAC)

In FDMA, the base STATION and the mobile station establish a duplex CHANNEL. The TWO directions, mobile station to base station and vice versa are separated using different frequencies. This Scheme is CALLED Frequency DIVISION Duplex (FDD)

In FDMA, the base station and the mobile station establish a duplex channel. The two directions, mobile station to base station and vice versa are separated using different frequencies. This Scheme is called Frequency Division Duplex (FDD)

Space Division Multiple Access (SDMA) is used for allocating separated spaces to users in WIRELESS networks. The BASIS for the SDMA ALGORITHM is formed by cells and sectorized antennas which constitute the infrastructure IMPLEMENTING space division multiplexing (SDM)

Space Division Multiple Access (SDMA) is used for allocating separated spaces to users in wireless networks. The basis for the SDMA algorithm is formed by cells and sectorized antennas which constitute the infrastructure implementing space division multiplexing (SDM)

In p-persistent CSMA system nodes also SENSE the medium, but only transmit with a probability of p. With the STATION deferring to the NEXT SLOT with the probability 1-p, i.e. access is slotted in addition.

In p-persistent CSMA system nodes also sense the medium, but only transmit with a probability of p. With the station deferring to the next slot with the probability 1-p, i.e. access is slotted in addition.

In, non-persistent CSMA, stations SENSE the carrier and start sending immediately if the medium is idle., if the medium is BUSY, the STATION pauses a random AMOUNT of time before sensing the medium again and repeating this pattern.

In, non-persistent CSMA, stations sense the carrier and start sending immediately if the medium is idle., if the medium is busy, the station pauses a random amount of time before sensing the medium again and repeating this pattern.

There are SEVERAL VERSIONS in CSMA, they are as FOLLOWS

• non-persistent CSMA
• p-persistent CSMA
• 1-persistent CSMA

There are several versions in CSMA, they are as follows

Code Division MULTIPLE Access systems use codes with certain characteristics to separate different users. To enable access to the shared MEDIUM without interference. The users use the same FREQUENCY and time to TRANSMIT data. The main problem is to find good codes and to separate this signal from noise. The good code can be FOUND the following 2 characteristic

1. Orthogonal.
2. AutoCorrelation.

Code Division Multiple Access systems use codes with certain characteristics to separate different users. To enable access to the shared medium without interference. The users use the same frequency and time to transmit data. The main problem is to find good codes and to separate this signal from noise. The good code can be found the following 2 characteristic

Spread Aloha Multiple ACCESS is a combination of CDMA and TDMA. The CDMA better SUITS for connection oriented services only and not for connection less bursty DATA traffic because it requires to program both sender and receiver to access different users with different CODES.

Spread Aloha Multiple Access is a combination of CDMA and TDMA. The CDMA better suits for connection oriented services only and not for connection less bursty data traffic because it requires to program both sender and receiver to access different users with different codes.