1、 Page|1 An FM Based Side Channel Communication System for Serial Link Training&Background Performance&Power Optimization Peter Krotnev,Huawei Technologies Qinghong Du,Huawei Technologies Andrew Marshall,Huawei Technologies Davide Tonietto,Huawei Technologies Page|2 Abstract To achieve a target margi
2、n at optimal energy efficiency both ends of the link need to be constantly optimized at the same time during normal link operation.Existing back channel communication methods cannot achieve these goals for several reasons.They can only be used at link initialization and are protocol dependent,or the
3、y require a physical side channel.They cannot operate across multiple link segments or between optical front panels.In this paper we present a Side Channel communication which is protocol agnostic,doesnt require a physical extra interface or channel,works continuously in the background without inter
4、fering with payload and mission mode operation or SI,doesnt require extra BW,doesnt require any relevant extra circuitry not already present in the vast majority of existing SerDes,can work seamlessly with links that use multiple repeaters and across optics and is not affected by channel impairments
5、.The system is based on FM modulation of the transmitter(s)clock(s).In the paper we outline various possible implementation schemes based on pre-existing,widely used SerDes architectures,which makes this system very easy to adopt without virtually any change in the existing hardware.System test resu
6、lts over a 112Gbps serial link are presented.Page|3 Author(s)Biography Peter Krotnev received Masters Degree in Telecommunications Engineering from the Technical University of Sofia in 1988.A Sr.Principal Engineer at Huawei Technologies,signal integrity expert and a member of the High Speed I/O Syst