Clock recovery and distribution solutions for all-IP RANs

RAD’s award-winning RAN (radio access network) gateways offer high-performance, robust synchronization solutions over packet-switched transport, with state-of-the-art clock recovery and distribution schemes and multi-standard TDM and ATM pseudowire support. Our cell-site and aggregation site gateways incorporate the following attributes to support operators in their migration to all-IP cellular backhaul:

Reconstruct original clocking data over packet, using standard pseudowire flows, to comply with G.823/824 synchronization interface requirements per G.8261 specifications

Interoperable with third-party radio network elements such as the Cisco 7600, Nortel MSS and Alcatel 7750

Support definite frequency accuracy limits for various services, including 50 ppb for GSM and 16 ppb for 2G CDMA and 3G UMTS

Designed to support the latest PTP (precision time protocol) IEEE 1588v2 standard

Feature holdover mechanism of 1ppb per 24 hours to protect against clock stream failures

Offer dedicated unicast or multicast pseudowires for clock distribution

Ensure QoS priorities for clock traffic

For packet transport to meet required “SDH/SONET or better” performance levels for mobile networks, there is a need for resilient clocking and synchronization schemes. Without proper mechanisms to negate the effect of impairments such as packet delay, delay variation and packet loss, all of which are inherent to packet-switched networks, operators run the risk of service disruptions, impaired cell hand-offs and excessive dropped calls.

As a result, accurate clock recovery and distribution methods have been developed to handle packet transport’s inefficiencies, capture the average transmission rate of the original bit stream, and distribute accurate timing information to all network elements. These methods include NTR, NTP, ITU-T G.8261, Synchronous Ethernet, and the recently approved IEEE 1588v2.

The pioneering author of various TDM over packet standards and a leader in the field of pseudowires, RAD has dedicated extensive efforts to the development of timing over packet solutions. To learn more, please refer to our ToP white papers: ITU-T G.823/824 Compliance in Packet Networks using Adaptive Clock Recovery and History of RAD’s Timing over Packet Solutions.