ETSI is now into the second phase of its work on NFV, having completed 11 specfications documents during its first phase.
ETSI
ETSI enters NFV Phase 2
C-RAN trial results
Work has started on producing 28 new documents and more are expected over the coming 2 years. The main objectives of this second phase of work are to encourage interoperability, building upon the achievements made in the first two years of the ISG. This new phase of work will include both normative and informative content. Adding normative requirements will provide the clarity required for interoperability and formal testing. Another key element of Phase 2 will be to work more closely with other standards bodies to help focus their work and to avoid duplication, and to collaborate within open source projects developing NFV implementations.
Power consumption down 41%
Rental expenses down 71%
Capex down 15% overall
Opex down 50% overall
d u o l C > n a R
Overview of China Mobile Cloud RAN Activities When it comes to virtualisation of the radio access network, no operator other than China Mobile (CMCC) has perhaps been more supportive of Cloud RAN; and for good reasons. China Mobile boasts over 800 million subscribers served by 900,000 GSM and 500,000 TD-SCDMA base stations. By mid 2014, China Mobile operated 410,000 TD-LTE base stations as part of a plan to roll out 500,000 by the end of 2014. However, like many wireless network operators, EBITDA margins are eroding and stand at 38% in 2013, down from 51% in 2009. Cloud RAN provides a solution to control costs by centralising baseband function in data centers to reduce energy, site rental and operational expenses. Cell sites account for 72% of CMCC energy consumption, 46% of which is due to HVAC. In one trial in Changdun where 506 GSM base stations were aggregated in a few centers, CMCC reported 41% reduction in power consumption due to shared air conditioning. In a second trial in Zhuhai where 18 new TD-SCDMA sites were rolled out in centralised configuration, site rental expenses are reduced by 71%. Today, 40% of the Zhuhai 3G network is centralised. In general, CMCC estimates that C-RAN saves up to 15% in capex and 50% in opex. As cell sites only have remote radios and antennas on premises, site roll out
time is reduced by a third. In addition to cost savings, Cloud RAN enhances performance especially at the cell edge. Field trials by CMCC show uplink CoMP gain for a 6-macrocells cluster is between 40~100% in weak coverage areas corresponding to increase in throughput between 1 – 2 Mbps. Similar if not higher gains are expected for heterogeneous network deployment where low power remote radios are used as small cells. CMCC continues to develop its strategy for Cloud RAN by conducting a number of field and market trials. In Jilin, 1400 GSM sites were centralised. In Guangzhou, CMCC deployed the first 3G/4G dual-mode network where the same remote radio is shared between the two technologies. Today, there are at least 5 field trials for TD-LTE in centralised configuration to evaluate different aspect of Cloud RAN. In these and other trials, CMCC relies heavily on its fiber assets for fronthaul. These assets will prove pivotal for the implementation of Cloud RAN as a single 20 MHz TD-LTE channel with 8x8 MIMO configuration requires 9.8 Gbps fronthaul data rate. Optimising the architecture of Cloud RAN to maximise its advantages while leveraging existing fibre infrastructure to minimise additional investments, is an evolving topic of study for the months to come. By Frank Rayal, XONA Partners
TMNQUARTERLY 39