t Ethernet Radios 100 Mbps 1.0 Gbps MPLS-TP Transport for NGMN IP over DWDM Frequency Spectrum LOS Unavailability -- High VSAT OPEX -- High Leased Lines OPEX Gigabit Ethernet Radios Shortages License-free Radios (for remote areas) Fiber Deployment Fiber CAPEX Fiber Cuts Gigabit Ethernet Radios Constraints TDM/IP Hybrid Radios TDM/ATM transition to IP ROW Traffic In-homogeneousness Traffic Aggregation MPLS-TP Figure 7.27 Transport challenges and potential solutions Summary Insights Chapter 7 provided details of the mobile transport network including its three segments, backhaul, metro network and backbone. A number of technological options for all these segments have been presented. Some backhaul network design and planning guidelines are also provided in the chapter. Later sections discussed the evolution of transport networks and perspective of the industry on the different emerging transport technologies. In summary, the challenges and drivers we discussed in this chapter can be addressed with a combination of high capacity microwave systems, Carrier Ethernet (MPLS-TP) and IP/MPLS solutions (Figure 7.27). The fundamental challenge is to find the right combination of transport technologies to address the problems at hand in a cost effective manner. References 1. Chia, S., Gasparroni, M., and Brick, P. (2009) The next challenge for cellular networks: Backhaul. IEEE Microwave Magazine, 10 (5), 54-66. 2. ITU-R Recommendation ITU-R P.676-7 (2007) Attenuation by atmospheric gases. 3. ECC Recommendation (05)07 (2009) Radio Frequency Channel Arrangements for Fixed Service Systems Oper- ating in the Bands 71-76 and 81-86 GHz, ECC with CEPT. 4. ETSI EN 302 217-3 (V1.3.1) (2009) Fixed Radio Systems; Characteristics and requirements for point-to-point equipment and antennas; Part 3: Equipment operating in frequency bands where both frequency coordinated or uncoordinated deployment might be applied; Harmonized EN covering the essential requirements of article 3.2 of the R&TTE Directive, ETSI, July. 5. Recommendation ITU-R P