Multi-acked multicast protocol

Abstract

Multicast transmissions do not allow for individual receivers to acknowledge that data was received by each receiver in the network. This is not acceptable for isochronous systems that require specific levels of QoS for each device. A multimedia communications protocol supports using multicast transmissions (one-to-many) in multimedia isochronous systems. A transmitter establishes a Multi-ACKed Multicast protocol within which a group of receiving devices can acknowledge the multicast transmission during a multi-acknowledgment period.

What is claimed is: 
     
         1 . A method, comprising:
 providing a contention period in which a transmitter is granted contention free access to a medium;   communicating using a Multi-ACKed Multicast protocol comprising:
 initialization of a multicast group of receivers by assigning an acknowledgement time within a multi-acknowledgment period based on Frame Length (FL) specified in a Start of Frame (SOF) delimiter; 
 transmitting by a transmitter of a multicast transmission comprising a first SOF delimiter and a medium access (MAC) data payload; 
 wherein the first SOF delimiter contains a first FL field that establishes a multi-acknowledgment period; 
 transmitting by each receiver of an acknowledgement at its acknowledgement time to the transmitter of the multicast transmission during the multi-acknowledgment period; and 
 wherein each acknowledgment contains a second FL field that indicates a time until the FL specified in the first FL field of the first SOF delimiter expires; and 
 terminating multicast transmission at the use of one of: a selective ACK (SACK) or expiration of the multi-acknowledgment period, 
 wherein communicating using the Multi-ACKed Multicast protocol is compatible and compliant with a native communications protocol. 
   
     
     
         2 . The method of  claim 1 , wherein the Multi-ACKed Multicast protocol is compatible and compliant because it does not affect interoperability with non-participating group receivers in the network that are using the native protocol. 
     
     
         3 . The method of  claim 1 , wherein the Multi-ACKed Multicast protocol is compatible and compliant because it may be terminated without affecting interoperability of any device in the network using the native protocol. 
     
     
         4 . The method of  claim 1 , wherein the acknowledgment time is established at one of: time of manufacture of the group of receivers or by a user of each receiver. 
     
     
         5 . The method of  claim 1 , wherein the acknowledgement time is calculated by the receivers based on an offset time multiplied by a device group sequence number. 
     
     
         6 . The method of  claim 1 , where the acknowledgement is a Reverse SOF (RSOF) delimiter containing the FL in the second FL field that is calculated to be equal to the time remaining in the FL of the first FL field. 
     
     
         7 . The method of  claim 1 , wherein the acknowledgement contains digital information about communications quality, further comprising using the digital information about communications quality by the transmitter to determine best parameters to use in a common Tone Map for subsequent multicast transmissions. 
     
     
         8 . The method of  claim 1 , further comprising:
 utilizing a second and subsequent SOF delimiter having a tone map for a subgroup of devices whose acknowledgment window falls after the first SOF but before one of: a subsequent SOF, or SACK or expiration of the multi-acknowledgment period;   wherein each tone map is used to optimize communications efficiency for that subgroup of receivers.   
     
     
         9 . The method of  claim 8 , further comprising: discontinuing the multicast transmission in favor of a native protocol method when the transmitter determines that the performance of the network is not as effective as a native protocol transmission. 
     
     
         10 . The method of  claim 9 , wherein the native distribution protocol method is unicast. 
     
     
         11 . A method, comprising:
 receiving by a receiver of a multicast transmission which includes a first start of frame (SOF) delimiter and a medium access (MAC) data payload, wherein the first SOF contains a first Frame Length (FL) field that establishes a multi-acknowledgment period;   responding by the receiver with a transmission of an acknowledgement at an acknowledgement time during the multi-acknowledgment period, wherein the acknowledgment contains a second FL field that indicates a time until a duration of the multi-acknowledgment period expires; and   calculating the acknowledgment time by the receiver based on an offset time multiplied by a device group sequence number.   
     
     
         12 . The method in  claim 11 , further comprising terminating multicast transmission in response to a selective ACK (SACK) by the receiver. 
     
     
         13 . The method in  claim 11 , further comprising terminating multicast transmission in response to expiration of the multi-acknowledgment period. 
     
     
         14 . The method in  claim 11 , where the acknowledgement is a Reverse SOF (RSOF) delimiter containing the second FL field. 
     
     
         15 . The method of  claim 11 , wherein the acknowledgement contains digital information about communications quality, further comprising using the digital information about communications quality to determine one or more best parameters to use in a common Tone Map for subsequent multicast transmissions. 
     
     
         16 . A multicast communications method for a carrier sense multiple access (CSMA) network, comprising:
 transmitting, by a transmitter, of a multicast transmission to a plurality of receivers comprising a first start of frame (SOF) delimiter, a second SOF delimiter and a medium access (MAC) data payload, wherein the first SOF delimiter contains a first Frame Length (FL) field that establishes a multi-acknowledgment period and wherein the multicast transmission is terminated by the use of one of: a selective ACK (SACK) by one of the receivers and an expiration of the multi-acknowledgment period;   wherein the second SOF delimiter contains a tone map that is optimized for a subgroup of receivers whose acknowledgment window falls at one of: after the second SOF delimiter but before a subsequent SOF delimiter, or SACK or expiration of the multi-acknowledgment period specified in the first FL field;   transmitting, by each of the receivers, of an acknowledgement at an acknowledgement time during the multi-acknowledgment period to the transmitter of the multicast transmission; and   wherein the acknowledgment contains a second FL field that indicates a time until a duration of the multi-acknowledgment period expires.   
     
     
         17 . The method in  claim 16 , wherein the acknowledgement time is established by one of: at time of manufacture of a group of devices which include the receivers or by a user of each receiver. 
     
     
         18 . The method in  claim 16 , wherein the acknowledgment time is calculated by each of the receivers based on an offset time multiplied by a device group sequence number. 
     
     
         19 . The method in  claim 16 , where the acknowledgement is a Reverse SOF (RSOF) delimiter containing the second FL field that indicates information calculated to be equal to a time remaining in the multi-acknowledgment period set by the first FL field. 
     
     
         20 . The method of  claim 16 , wherein the acknowledgement contains digital information about communications quality, further comprising using the digital information about communications quality by the transmitter to determine one or more best parameters to use in a common Tone Map for subsequent multicast transmissions. 
     
     
         21 . The method of  claim 16 , wherein each tone map is used to optimize the communications efficiency for that subgroup of receivers. 
     
     
         22 . The method of  claim 16 , wherein a link identification (LID) is used by different SOF delimiters to create separate subgroups of receivers. 
     
     
         23 . The method of  claim 16 , wherein the acknowledgment contains digital information about communications quality, and further comprising using the digital information about communications quality by the transmitter to group the receivers into subgroups that share a subgroup-specific Tone Map that is optimized for that subgroup; wherein the Tone Map is used by the SOF delimiter and the devices within the subgroup are assigned to acknowledgement times at one of: after the SOF delimiter and before a subsequent SOF, or SACK or expiration of the multi-acknowledgment period specified by the first FL.