Method for enhancing fairness and performance in a multihop ad hoc network and corresponding system

A system to enhance fairness and performance in a multihop ad hoc network, the system comprising:

• a first processor configured to provide contention synchronization information regarding a transmission between a first set of nodes of the network, and configured to provide the information to a second set of nodes in a range of two hops from the first set of nodes participating at the transmission;
• a second processor configured to set a waiting time for the first set of nodes after a successful finish of the transmission, in which the first set of nodes backoff from accessing a transmission medium;
• a first node configured to receive a transmission request or a transmission clearance, and configured to generate a black burst energy signal by each such receipt, the black burst energy signal indicating a busy time of the transmission medium according to a mapping scheme to provide the contention synchronization information;
• and
• a wireless local area network,
• wherein, in the first node, the transmission request comprises a request-to-send packet, the transmission clearance comprises a clear-to-send packet, and the waiting time comprises a time for a request-to-send/clear-to-send-handshaking and a total backoff time of a minimum contention window.

A wireless local area network node, wherein:

• the node is configured to back off using a random value uniformly chosen between 0 and CWmin before accessing a channel, when a packet arrives to a Medium Access Control Layer from a higher layer;
• the node is configured to generate a black burst energy signal according to a mapping scheme, when the node receives a request-to-send or clear-to-send not for itself, wherein the black burst energy signal is not sent if the node detects the channel is busy;
• the node is configured to receive the black burst energy signal and attempts to access the channel for limited times before an end point of a time indicated by the black burst energy signal, wherein these attempts are not added to retransmission times for the packet;
• the node is configured to start a backoff timer at the end point of the time indicated by the black burst energy signal by using a random value uniformly chosen between 0 and CWmin, while a contention window for the node is not reset, if the node detects the channel is idle,
• wherein only an earliest time point is used if more than one black burst energy signal is received;
• and
• the node is configured to wait for a time period after a successful transmission, before the channel is accessed again, wherein length of the time period comprises a time for a request-to-send/clear-to-send-handshaking and a total backoff time of a minimum contention window.