A comparison of subwavelength optical switching networks for LTE mobile backhauling

Optical slot switching is a networking technology that can provide statistical multiplexing energy-efficiently. In this paper, we propose and study the dimensioning of two such sub-wavelength granularity optical transport technologies applied to mobile traffic backhauling in LTE cellular networks. In particular, we focus on Time-Domain Wavelength Interleaved Network (TWIN), which exploits optical slot switching in mesh networks, and on Packet Optical Add/Drop Multiplexers (POADM), which exploits optical slot switching over rings. TWIN and POADM are compared for the first time in terms of the network planning cost, in a small but realistic mobile backhaul scenario. The traffic in LTE is composed of unicast and multicast part; the latter can be driven by IPTV and Coordinated MultiPoint transmission (CoMP), a joint transmission/receiving technology for better user experience. We propose 3 different methods to support the multicast traffic. Simulations compare the efficiency of different multicasting techniques in terms of the needed resources, and indicate the suitable networking scenario for each of the optical slot switching technique.