Real-Time Demonstration of Concurrent Upstream and Inter-ONU Communications in Hybrid OFDM DFMA PONs

This paper presents the first real-time experimental demonstration of concurrent upstream and inter-ONU communications in a hybrid OFDM DFMA PON, enabled by a simple low-cost alteration to the remote node. Real-time FPGA-based DSP, incorporating a 128-pt FFT and a joint sideband processing technique, is used to demultiplex different sub-wavelength channels at the ONU and OLT receivers. The simple modification in the remote node removes the need for direct user-to-user data to pass via the OLT and core network thus providing ultra-low latency inter-ONU connectivity to support a variety of newly emerging latency sensitive 5G services. The presented PON is validated with two subwavelength bands, each capable of carrying one of two possible orthogonal channels ( I or Q ). The dynamic channel and subcarrier allocation allows flexible allocation of PON capacity between upstream and inter-ONU links for dynamic on-demand capacity allocation and also performance optimisation according to the different length dependent link characteristics. Moreover, the backscattering effect associated with upstream signals is shown to have negligible effect on the BER performance of the inter-ONU communications

Using Responsive Evaluation to Evaluate a Professional Conference

In a statewide conference on alternative methods for assessing students’ learning, we incorporated responsive evaluation methods into the structure of the conference. The application of these interactive evaluation techniques serves as a pilot study that illustrates the possible utility of these tech-niques in evaluating conferences. This paper provides a brief review of the literature surrounding responsive evaluation, a description of the responsive evaluation methods applied to this conference, and a discussion of the results and implications of this pilot study