Mobile TV, mobile video, mobile advertising, mobile search … in the early days of cellular telephony none of these functions occurred to the few who could afford a mobile phone. Based on years of relatively small advances with hardwired phone units, and weighed down with bulky mobile handsets and batteries, it was hard to imagine cell phone would so quickly evolve into the smart, lightweight phones of today. In extreme contrast with the voice only use of early mobile, modern day users are increasingly familiar with web surfing, cyber payments, online gaming and more. Globally, mobile operators are striving to popularize mobile broadband services, the ARPU contributions from which are steadily rising. In Europe, the income derived from broadband mobile services is over 20 percent of total revenue and, in Japan and Korea, it already exceeds 30 percent.
Huawei believes the mobile communications market will continue to support traditional voice services as a basic communication tool while incorporating the expectation that integrated, convergent, and broadband services will emerge as dominant. A dominant evolutionary goal for mobile networks is convergence with the Internet. Rapid development of mobile broadband services will therefore impose new demands on base stations' air interface and backhaul technologies; in turn this will trigger essential transport network transformation.
The development of mobile communications technologies is represented by high-speed packet access (HSPA), WiMAX, and Long-Term Evolution (LTE) systems. In the HSPA mobile system, for example, a WCDMA network can evolve into HSDPA, HSxPA, eHSPA, or LTE, and the air interface bandwidth will be expanded from 384 kb/s respectively to 14.4 Mb/s downlink + 5.76 Mb/s uplink, 25 Mb/s downlink + 12.5 Mb/s uplink, or 100 Mb/s downlink + 50 Mb/s uplink.
The evolution of mobile backhaul involves three stages aligned to mobile broadband development: start-up, growth, and maturity. In the start-up phase, very few broadband base stations are deployed, and few FE interfaces emerge in mobile networks. At the outset, bandwidth demands on mobile backhaul are relatively low. The growth stage sees an increase in the number of broadband base stations with equivalently increased bandwidth needs. The most significant feature at this point of evolution is the coexistence of broadband and narrowband base stations. The maturity stage involves replacing or upgrading most narrowband base stations. Essentially all of Huawei’s new base stations are built to be broadband in nature. Whether an operator network is optical-, microwave- or copper-based, Huawei is prepared with solutions for each stage of evolution.
In this age of narrowband base stations, operators who build their own transport networks have already constructed large-scale optical transport networks as represented by NG-SDH/MSTP. Backhaul network bandwidth is sufficient to support future base station capacity expansion. The operators can meet bandwidth requirements by upgrading NG-SDH/MSTP equipment, replacing 155 Mb/s SDH rings with 622 Mb/s SDH rings or by dividing a 155 Mb/s ring into two 155 Mb/s rings. For operators employing leased lines, Huawei recommends construction of proprietary fiber or microwave transport networks in order to cut down exorbitant leased line expenditures.
In the start-up stage, Huawei's experience shows that existing microwave devices in the backhaul network can be upgraded to meet the bandwidth requirements in certain sections of broadband base stations. If the corresponding interfaces are IMA E1, then large-capacity E1 modules can be added to the microwave devices to expand bandwidth. If they are FE, interface cards can be introduced to the microwave devices to implement hybrid transport of FE and E1. Existing microwave devices located at the convergence point can adopt simple L2 convergence to improve bandwidth utilization. The internal, multiple add/drop multiplexer (MADM) or switching dispatch capability can convert microwave transmission links to networks in order to achieve carrier-class protection switching.
During the start-up stage, bandwidth needs related to copper cable transport networks are fairly low, and operators who own or rent cable resources can use G.SDHSL technology to support E1/FE traffic access from base stations. If the traffic loads on a single copper cable of a base station exceed 2 Mb/s, G.SDHSL wire bonding technology can achieve a transport capacity of 5.6 Mb/s.
