Lossless data delivery at route changes in wireless radio networks

Abstract

The described technology is generally directed towards lossless delivery of data when there are route changes, e.g., in an integrated access and backhaul (IAB) multi-hop relay network. When a route changes is to occur, the last unchanged node in a multiple hop route preserves the data (e.g., copies unacknowledged and unsent PDCP PDUs from the protocol stack corresponding to the radio link control layer of the failed relay hop, and populates a replacement protocol stack for the node in the new route with the preserved data. Also described is pre-emptive detection of link failure, which triggers a route change based on monitoring retransmissions to detect a deteriorating link, which can occur before complete link communication failure.

What is claimed is: 
     
         1 . A method, comprising,
 based on a detected condition, changing, by a network node comprising a processor, a route that comprises the network node, comprising:
 switching from a next network node in the route adjacent to the network node to a replacement next network node; 
 copying unacknowledged and unsent data units maintained in a first protocol stack associated with the next network node; 
 populating the unacknowledged and unsent data units in a second protocol stack associated with the replacement next network node; and 
 transmitting the unacknowledged and unsent data units to the replacement next network node before transmitting any new data units that are received from an incoming link and are destined for the replacement next network node. 
   
     
     
         2 . The method of  claim 1 , wherein copying the unacknowledged and unsent data units comprises copying the unacknowledged and unsent data units from a first radio link control layer of the first protocol stack, and wherein populating the second protocol stack comprises populating the unacknowledged and unsent data units in a second radio link control layer of the second protocol stack. 
     
     
         3 . The method of  claim 1 , further comprising resetting, by the network node, the first protocol stack after copying the unacknowledged and unsent data units of the first protocol stack. 
     
     
         4 . The method of  claim 1 , wherein the detected condition comprises a deterioration of a radio link between the network node and the next network node. 
     
     
         5 . The method of  claim 4 , wherein the deterioration of the radio link comprises control retransmissions satisfying a function of a threshold value. 
     
     
         6 . The method of  claim 1 , wherein the detected condition comprises a failure of a radio link between the network node and the next network node. 
     
     
         7 . The method of  claim 1 , wherein the replacement next network node is a backup network node predefined as the backup network node. 
     
     
         8 . Network equipment, comprising:
 a processor; and   a memory that stores executable instructions that, when executed by the processor, facilitate performance of operations, the operations comprising:
 altering a route comprising hops based on a criterion, wherein the network equipment is a hop in the route, comprising:
 determining to switch from a next hop in the route adjacent to the hop to a replacement hop; 
 copying unacknowledged and unsent data maintained in a first protocol stack associated with the next hop; 
 populating the unacknowledged and unsent data in a second protocol stack associated with the replacement hop; and 
 transmitting the unacknowledged and unsent data to the replacement hop before transmitting any new data received that is to be sent to the replacement hop. 
 
   
     
     
         9 . The network equipment of  claim 8 , wherein copying the unacknowledged and unsent data comprises copying the unacknowledged and unsent data from a first radio link control layer of the first protocol stack, and wherein populating the second protocol stack comprises populating the unacknowledged and unsent data in a second radio link control layer of the second protocol stack. 
     
     
         10 . The network equipment of  claim 9 , wherein the operations further comprise resetting the first radio link control layer after copying the unacknowledged and unsent data units of the first radio link control layer. 
     
     
         11 . The network equipment of  claim 8 , wherein the criterion comprises a degradation of a communication link between the hop and the next hop. 
     
     
         12 . The network equipment of  claim 11 , wherein the degradation of the communication link comprises a quantity of retransmissions being determined to have transitioned a threshold value. 
     
     
         13 . The network equipment of  claim 8 , wherein the criterion comprises a failure of a communication link between the hop and the next hop. 
     
     
         14 . The network equipment of  claim 8 , wherein the replacement hop is predefined as a backup hop for the next hop. 
     
     
         15 . A non-transitory machine-readable medium, comprising executable instructions that, when executed by a processor of integrated access and backhaul equipment, facilitate performance of operations, the operations comprising:
 modifying a route comprising nodes based on a criterion, wherein the integrated access and backhaul equipment is comprised in a node in the route, comprising:
 switching from a next node in the route adjacent to the node to a replacement node; 
 copying unacknowledged and unsent protocol data units maintained in an existing protocol stack associated with the next node; 
 populating the unacknowledged and unsent protocol data units in a new protocol stack associated with the replacement node; and 
 transmitting the unacknowledged and unsent protocol data units to the replacement node before transmitting any new protocol data units received that are to be sent to the replacement node. 
   
     
     
         16 . The non-transitory machine-readable medium of  claim 15 , wherein copying the unacknowledged and unsent protocol data units comprises copying the unacknowledged and unsent protocol data units from a first radio link control layer of the existing protocol stack, and wherein populating the new protocol stack comprises populating the unacknowledged and unsent protocol data units in a second radio link control layer of the new protocol stack. 
     
     
         17 . The non-transitory machine-readable medium of  claim 16 , wherein the operations further comprise resetting the first radio link control layer after copying the unacknowledged and unsent data units of the existing protocol stack. 
     
     
         18 . The non-transitory machine-readable medium of  claim 15 , wherein the criterion comprises a degradation of a communication link between the node and the next node. 
     
     
         19 . The non-transitory machine-readable medium of  claim 18 , wherein the degradation of the communication link comprises a quantity of retransmissions being determined to have reached a threshold value. 
     
     
         20 . The non-transitory machine-readable medium of  claim 15 , wherein the criterion comprises a failure of a communication link between the node and the next node.