Synchronization controller cuts costs in mobile networks

For the introduction of femtocells in the telecom market, distribution of precise time and frequency is a major challenge for a mass deployment in the heterogeneous networks. The high cost for achieving the required accuracy has been a barrier for this emerging consumer market. The operator defined price target of $100 is easily upset by the cost of the clock reference technologies alone. Imsys offers products based on IEEE 1588 technology to overcome this.

While current industry solution providers see challenges in achieving a 100ns timestamp accuracy, the Imsys technology delivers a 10-fold better performance running from its internal oscillator. Where existing solutions require an additional switch and an extra IP address from the operator, Imsys can share the IP address with the local network processor in designs with data payloads up to 60Mbit/s.

Precise time with nanosecond accuracy, synchronized to UTC (Coordinated Universal Time), is made possible by the Precision Time Protocol (PTP) IEEE 1588 version 2. The Imsys IM3240 IC can distribute stratum 1 accuracy over the packet-switching Ethernet, with a reference signal from a GPS receiver. Synchronized time can now become commodity for use in networked systems. An IM3240-based Edge GrandMaster can act a local area network service provider of time and frequency to clustered small cell base stations in the new generation mobile networks.

The functionality is delivered by the IM3240, an application specific controller with an integrated hardware Time Stamp Engine (TSE) for Ethernet based protocols. In implementing the IEEE 1588 protocol software the IC delivers highest accuracy, with a peak-to-peak error of 11ns in the timestamping of PTP messages, compared to the GPS input reference.

The features of the IM3240 make it suitable for new generation mobile networks as they now move indoors. In grandmaster mode it will transmit its GPS based reference to other nodes. When operating in slave mode and without a GPS signal it will use one of the network's grandmasters as reference.

The value of the IP network time and synchronization controller IM3240 is clear when comparing total cost of implementing the Ethernet connection, communication stacks and synchronization in a slave application. As part of the data path it supports up to 60Mbit/s layer 2 designs in the network, requiring only one IP address for most applications.

"Now system developers of 4G infrastructure have a viable technical solution which also supports their low cost targets. Looking at the development cycle, we can reduce the time for working prototype from months to days due to the high level of integration. The customers can concentrate on the wireless side of things," said Ola Andersson, Imsys president and CEO.

The IM3240-P40 from Imsys is an OEM board for developing products for this application. Connected to a low cost GPS receiver with a Pulse Per Second output signal, it will prototype a PTP GrandMaster in no time. All necessary hardware and software is included. The small form factor (83mm x 50mm) and design quality of the Imsys IM3240-P40 platform enables compact design and OEM prototyping with a roadmap to optimizations.