CHANNEL ACCESS CONTROL PERFORMANCE IN SATELLITE COMMUNICATION
MAC protocols are created to coordinate the transmission of packets, retransmission of damaged packets, and resolution of collisions between stations within a contention period. The MAC protocols include fixed assignment protocol, demand assignment protocol, random access protocol, reservation protocol, cross of reservation protocol and random gain access to protocols and adaptive protocols. Satellite connection systems have typically been made for voice targeted traffic. Multiple get protocols intended for conflict resolution have typically recently been channel-oriented with either set or require assignment. Data communications, nevertheless , have a lot more diverse visitors characteristics and transmission requirements than tone communications. A great access process suitable for wideband pack satellite network portion a limited number of bursty buffered users is suggested. The overall performance of the proposed scheme is evaluated which is compared with other protocols. Several stratergies in making reservations are thought. The efficiency criteria contain high channel throughput, low transmission wait, channel steadiness and low complexity.
The MACINTOSH sublayer supplies addressing and channel access control systems that make it possible for several terminals or network nodes to communicate within a multiple gain access to network that incorporates a shared method, e. g. Ethernet. The hardware that implements the MAC is known as a channel access control mechanism. The MAC PC sublayer acts as an software between the logical link control (LLC) sublayer and the network's physical coating. The MACINTOSH layer emulates a full-duplex logical interaction channel within a multi-point network. This route may provide unicast, multicast or transmission communication assistance.
FIXED-ASSIGNMENT MULTIPLE ACCESS PROTOCOLS
In fixed-assignment multiple get protocols, the allocation of channel bandwidth to a place is a static assignment which is independent of stations actions. This is created by partitioning the bandwidth space into slot machines, each given to a stop. Suitable once stations generate a steady stream of information that that makes useful use of dedicated channel.
FREQUENCY DIVISION MULTIPLE ACCESS
The regularity division multiple access (FDMA) channel- access scheme will be based upon the frequency-division multiplex (FDM) scheme, which provides different consistency bands to be able to data-streams. In the FDMA case, the data fields are invested in different nodes or equipment. In FDMA no coordination or synchronization is required. Each station may use its own music group without interference. This technique has the advantage of simpleness, but lacks flexibility and re-configurability.
PERIOD DIVISION MULTIPLE ACCESS
Enough time division multiple access (TDMA) channel get scheme is dependent on the time division multiplex (TDM) scheme, which provides different time-slots to different data-streams. For example , station 1 might use time position 1, place 2 period slot a couple of, etc . before the frame ends. Then it begins all over again, within a repetitive style, until every data is transmitted and that slot becomes free or assigned to a new station. TDMA provides better channel throughput. In general TDMA (G-TDMA), the allowance of bandwidth to a station is proportionate to the volume of targeted traffic generated by station, thus higher throughput can be achieved.
CODE SPLIT MULTIPLE ACCESS
A conflict-free protocol that allows overlap tranny, in both equally frequency-division and time-division methods, is CDMA or spread spectrum multiple access. The code department multiple get (CDMA) system is based on pass on spectrum. Down sides: higher difficulty of a receiver. All signals should have similar strength for a device. Advantages: Every terminals can use the same frequency. Forward problem correction and encryption could be easily built-in. Since were interested in the...
References: п‚— Medium Access Control Protocol in Satellite Conversation, Hassan Peyravi, Kent Condition University. (IEEE communications journal march 1999)
п‚— Communication Sites (Basic Concepts And Essential Architectures)- alberto leon- garcia & indra widja
п‚— Medium Access Control Protocols for Space and Satellite television Communications: A Survey and Assessment, L. Peyravi
п‚— Satellite Box Communication-Multiple Get Protocols and gratification. - Claire S. Lam, member, IEEE (IEEE orders on communications, vol. com-27, no . 10, october 1979).