Sense Multiple Access

At the time it was considered the only specification of technology of last mile of the industry of net capable to reach speed of up to 240 Mbps (JNIOR, 2004), HomePNA 3,0 obtained this characteristic through implementations based on the G.9954 recommendation, transport of data with inherent requirements of QoS (Quality of Service) and with the new potentialities of the Media Access Control (MAC) used in version 3.0, that they allow that the users attribute spaces of time in the transmission of the data, guaranteeing, in this manner, the delivery of the data in Real-teams under a predetermined project of 7 latency that was projected to hinder interruptions ofthe signal.

This comes well to the meeting of the necessities of the applications multimedia. With this expanded potentiality of QoS (quality of service), one expects to allow that the service suppliers can offer to services of games on-line with access of high speed, directly for the Internet; the transmission of video on-demand on the net also can be used in this version of the HomePNA. In the MAC (Media Access Control) of version 3.0 of the HomePNA the CSMA/CA was introduced (Carrier Sense Multiple Access with Collision Avoidance) that it integrates a new system of synchronism together with the CSMA/CD (Carrier Sense Multiple Access with Collision Detection), SMAC (Synchronous MAC). The system of priorities used is based on the HomePNA version 2.0. The SMAC is used to guarantee the width of band, latency, jitter that it is the variation statistics of the retardation in the delivery of data in a net that can be defined as the measure of variation of the delay enters the successive packages of dadose the BER/PER characteristics (Bit Error Rate)/(Priority Error Rate) to support the synchronous and asynchronous transactions and to provide the function with QoS. To assist in the control of the collisions, HomePNA 3,0 uses DFPQ (Distributed Fair Priority Queuing), a distributed procedure of resolution of collision.