5G Mobile Networks use much higher radio frequency bands, Massive MIMO and Beamforming technologies which require bringing Remote Radio Unit (RRU) closer to the end users and therefore much denser RRU distribution. Centralized Radio Access Networks (CRAN) are favored by many Mobile Network Architects, where remote BBU farms are built in centralized equipment rooms from where services are provided to many RRUs. Such approach fastens the 5G roll-out, reduces space requirements and rental costs in remote sites, improves maintenance and significantly simplifies transport network architecture.

Passive DWDM (Dense Wavelength Division Multiplexing) is a cost efficient approach which can be used in 5G CRAN design to interconnect BBU farms to RRUs. Passive DWDM solution consists of colored optical transceivers which are used together with passive DWDM filters. DWDM eCPRI 25G SFP28 optical transceivers use a DWDM channel plan defined by ITU-T G.694.1 (more specifically 45 channels, from Channel 17 to Channel 61 in DWDM C-Band spectrum with 100Ghz channel spacing) and with help of passive DWDM filters we can aggregate/separate different wavelength (nm) connections.

If we use double fiber between BBU farm and RRUs with passive DWDM we can have up to 45 Channel interconnection or if we use single fiber we can have up to 22 Channel DWDM eCPRI connection.

In addition, 25G Tunable DWDM SFP28 transceivers are an excellent option for those seeking added flexibility and ease in their 5G eCPRI DWDM network implementation. Modules provide 48 Tunable Channels across the ITU-T 100Ghz C-Band grid, specifically from Channel 13 to Channel 60 (191.3196.0 THz). 25G Tunable DWDM modules also support Wavelength auto-tuning functionality, which can drastically reduce the time required for service launch.

DWDM eCPRI 25G modules support latest 5G Fronthaul bit rate requirements and such applications as CPRI Option 10 (24.33 Gbps), CPRI Option 9 (12.165 Gbps), CPRI Option 8 (10.138 Gbps) and CPRI option 7 (9.830 Gbps) at the same time our DWDM CPRI 25G SFP28 optical transceivers are backwards compatible with older generation 4G/3G Mobile Base Stations.