Mobile fronthaul over latency-optimized time division multiplexed passive optical networks

Transport of mobile fronthaul traffic has a tight latency requirement of about 250us one-way. The best solutions today are based on expensive point-to-point (PtP) fiber links and PtP wavelength division multiplexing. A time division multiplexed passive optical network (TDM-PON) is less expensive, but has a poor latency of about 1ms. Guidelines are suggested to design an optimized TDM-PON with minimal latency for transport of constant bit rate fronthaul traffic. The total latency is mathematically analyzed using queuing theory, and closed-form formulas are derived which allow study of the trade-offs enabled by the different parameters. Feasibility of acceptable levels of latency of 250us or less is established in several application scenarios.