Nortel Networks Corporation

Apple Inc.

Richard Thomas

Peter Arnold Giese

Jowan Masum-Thomas

Stephane Roch

Andrew V Maroney

Christopher R Fludger

A radio access network includes a transport network layer; a radio network layer having a layer 2 network for communicating between entities within the radio network layer by exchanging datagrams having a predetermined format used only within the radio network layer. Accordingly, the present invention provides for a true decoupling at layer 2 between the radio network layer and the transport network layer. Addressing at layer 2 can enable both connectionless and connection oriented using an overlay connectivity model. Layer 2 in the radio network layer is implemented as an Ethernet network.

Transport for wireless radio access networks

In a first aspect, a Raman amplifier is pumped using pumps just above and below the fiber water peak. This enables lower power pumps to be used, as the high attenuation is avoided. In a second aspect, a first pump provides a signal having a first wavelength and a first power, and a second pump source provides a plurality of signals, each having a power lower than the first power and a wavelength in a range approximately one Stokes shift higher than the first wavelength. In this way, the second pump source signals are amplified by the Raman effect by the first pump source signal, and the amplified second pump source signals cause signal amplification. The amplified second pump source signals can then include wavelengths above and below the water peak.

Raman amplification

An optical amplifier has at least first stage in the form of a distributed Raman amplifier and a second stage in the form of a discrete Raman amplifier. The discrete amplifier has an output for unused pump power, and the distributed Raman amplifier is pumped using the unused pump power from the second stage. This arrangement enables unused pump power to be used in a distributed Raman amplifier, in particular using the transmission fiber at the input to the second stage amplifier.

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Nepean, Canada

Richard Thomas