Demonstration of end-to-end cloud-DSL with a PON-based fronthaul supporting 576-Gb/s throughput with 48 eCDMA-encoded 1024-QAM discrete multi-tone signals

Abstract

We experimentally demonstrate an end-to-end ultra-broadband cloud-DSL network using passive optical network (PON) based fronthaul with electronic code-division-multiple-access (eCDMA) encoding and decoding. Forty-eight signals that are compliant with the very-high-bit-rate digital subscriber line 2 (VDSL2) standard are transmitted with a record throughput of 5.76 Gb/s over a hybrid link consisting of a 20-km standard single-mode fiber and a 100-m twisted pair.

High speed OFDM-CDMA optical access network

“…If the OFDM-based transmitters and receivers are encoded and decoded with orthogonal codes, they can benefit from dense subcarrier spacing, ease of equalization, multiple access, and crosstalk cancellation. Hence the combination of OFDM and CDMA has been shown to be a potential important evolution route for future low-cost and high-speed NG-PONs [7,8]. Building on this concept, we implement a system using an OFDM modulation scheme which then encounters CDMA encoding/decoding separately for each user for high-aggregate data rates.…”

“…Different from [7,8], the signals are mapped into all the OFDM subcarriers and then the OFDM symbols in each user are spread and encoded using a unique Walsh-Hadamard code rather than the reverse order. Now the nth CDMA encoded OFDM symbol can be written as y q c l modq;M x ⌊q∕M ⌋ ; q 0; 1; 2; …MN − 1:…”