NG-PON - TDMA or WDM?

Today, there is a major trend in broadband metro access networks towards FTTx (Fiber-To-The-x, where x stands for Home (H), Building (B), Curb, or Cabinet). FTTx can be based on active Point-to-Point/Ethernet, or Passive Optical Networks (PON). Many agree that PON-based FTTH/FTTB will win mid- to long-term over other deployment scenarios because of high bandwidths at comparatively low cost. However, there is also debate as to whether or not the future passive access network should be based on Time-Domain Multiple Access (TDMA, as known from GPON and EPON) or on WDM/WDMA (Wavelength-Domain Multiple Access). In this paper, we analyze requirements for the unified next-generation access and backhaul infrastructure. We conclude that this infrastructure should be based on WDM rather than TDMA in order to accommodate future band-width requirements whilst at the same time supporting backhaul and business access applications most efficiently.