MAC protocol requirements for OFDMA-PONs

This paper provides specifications of the parameters defining the design of medium access control (MAC) protocols for orthogonal frequency division multiple access (OFDMA) passive optical networks (PONs). A dynamic bandwidth allocation (DBA) algorithm exhibiting service level agreement (SLA) has displayed packet delays of less than 1.5 ms for the middle and high SLA optical network units (ONUs) at 156 Mbps, representing the maximum ONU offered load. A spectral efficiency of 93.75% the total network capacity of 40 Gbps has been achieved, for 256 ONUs and long-reach link lengths of 100 km. The new protocol functionalities have been attained by the extension of the XG-PON frame structure to demonstrate OFDMA/TDMA granularity.

1. INTRODUCTION

Orthogonal frequency division multiple access (OFDMA) Passive Optical Networks (PONs) have been gaining in capacity, reach and cost [1], in response to the targets of next generation access networks. Consolidating the requirements in service provisioning, including Ultra High Definition Television (UHDTV), 3-Dimensional TV (3DTV) and business E-Line Point-to-Point (P2P) to mention a few, the guaranteed bit rates of residential users and small businesses are expected to grow symmetrically to 400 Mbps [2]. In addition corporations and telco services require bandwidths of several tens of Gbps while base stations for long term evolution advanced (LTE-A) backhauling up to 3 Gbps per site [3]. To attend to these requirements, the FP7 project ACCORDANCE [4] aims, besides the physical layer, to develop new medium access control (MAC) designs for OFDMA-PONs.