Microsoft Technology Licensing, LLC

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Daehyeok Kim

Anuj Kalia

Paramvir Bahl

Tao Ji

Nikita Lazarev

Methods and systems for dynamically re-routing layer traffic between different servers with little user-visible disruption and without modifications to the vRAN software stack are provided. For instance, transformations on messages between the L2 and PHY, such as duplication and filtering, enable the system to maintain one or more low-overhead 'hot, inactive' PHY clones. A hot, inactive PHY clone may be a duplicate of an operational PHY, where the PHY clone is primed to process a PHY workload of the operational PHY (e.g., “hot”) but is not currently responsible for processing the PHY workload (e.g., low-overhead, inactive). In this way, a PHY workload may be automatically and seamlessly migrated to the hot PHY clone in response to planned downtime (e.g., scheduled maintenance, software upgrades) or unexpected events (e.g., server failures) within the strict transmission time intervals (TTIs) required for processing the PHY workload.

Creating elasticity and resiliency in virtualized RANs

Methods and systems for dynamically re-routing layer traffic between different servers with little user-visible disruption and without modifications to the vRAN software stack are provided. This approach enables operators to initiate a PHY migration either on demand (e.g., during planned maintenances) or to set up automatic migration on unexpected events (e.g., server failures). It is recognized that PHY processing in cellular networks has no hard state that must be migrated. As a result, layer traffic such as the PHY-L2 traffic or L2-PHY traffic can be simply re-routed to a different server. This re-routing mechanism is realized by interposing one or more message controllers (e.g., middlebox) in a communication channel between the PHY and L2.

Dynamic re-routing and modification of layer traffic in virtualized RANs

Described are examples for providing a distributed fault-tolerant state store for a virtualized base station. In an aspect, a first server at a datacenter may perform physical layer processing for at least one virtualized base station. While performing the physical layer processing, the first server may generate inter-slot physical layer state data during a first slot. The inter-slot physical layer state data is to be used in a subsequent slot. The first server may periodically transmit the inter-slot physical layer state data to one or more other servers of the plurality of servers within the datacenter. One of the other servers may take over the physical layer processing for the at least one virtualized base station based on the inter-slot physical layer state data, for example, in response to a fault at the first server or a migration of the at least one virtualized base station.

Distributed fault-tolerant state store for virtualized radio access networks

Described are examples for providing cell level migration of physical layer processing in a virtualized base station. A system for operating virtualized base stations includes a plurality of physical layer (PHY) servers within a datacenter and a media access control (MAC) server. Each respective PHY server includes: a memory storing instructions and at least one processor coupled to the memory. The at least one processor is configured to perform physical layer radio access network processing for a cell at the respective PHY server. The MAC server includes a memory storing instructions and at least one processor coupled to the memory. The at least one processor is configured to migrate the physical layer radio access network processing for the cell from a first server of the plurality of PHY servers to a second server of the plurality of PHY servers within the datacenter at an inter-slot boundary.

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