In pursuit of higher-capacity and higher-throughput signals, wireless operators have firmly established Long-Term-Evolution (LTE) networks in the United States. With the majority of mobile subscribers using these networks, operators are in the process of upgrading their LTE infrastructure to keep up with the rapidly growing demand for wireless data. According to a recent report from iGR Wireless Research, spending on LTE technology will continue its meteoric rise through 2020.
The report, which evaluated wireless operators throughout the United States, anticipates that about $212 billion will be spent on installing and operating LTE networks over the next five years. According to Iain Gillot, iGR president, “[This] expenditure will include both building and operating LTE networks, networks that will increasingly be densified with metrocells, remote radio heads, and distributed antenna systems."
To support additional LTE capacity, wireless operators have started to recycle spectrum previously used for 2G and 3G communications. Two years ago, AT&T began refarming 2G spectrum in the 1,900 MHz PCS band to be replaced with LTE signals. More recently, operators have begun to focus their attention on reusing the 1,800 MHz spectrum. In addition to these recycling programs, operators are still acquiring spectrum through federal auctions and private transactions. For instance, the Federal Communications Commission (FCC) has scheduled an auction early next year for 600 MHz television broadcast spectrum, which is expected to earn in the region of $60 billion.
The widespread appeal of LTE technology can largely be attributed to its ability to navigate heterogeneous network (HetNet) infrastructure—a patchwork quilt of network coverage that uses a multitude of access technologies. The LTE-Advanced (LTE-A) standard, for instance, is designed with enhanced inter-cell resource and interference coordination (eICIC) and terminal receivers with interference cancellation (IC), which together allow wireless operators to deploy small cells and macrocells over the same channel.
These features are growing increasingly important, as macrocells are slowly losing support to strategically deployed small cells and other access points. According to a recent report from SNS Research, macrocell alternatives will account for over 80% of all mobile broadband traffic by 2020.
The iGR report predicts that subsequent versions of the LTE standard will serve as the bridge to 5G wireless networks. Many analysts predict that LTE-A features, such as carrier aggregation and LTE in the unlicensed spectrum (LTE-U), which are being deployed in the latest smartphones, will eventually be incorporated in 5G technologies. That the iGR report stretches through 2020 is also significant, because that is when the first commercial 5G wireless networks are expected to be introduced.
Watch this video from the 3GPP for a brief description of the upcoming Release 13 and the organization's timeline for 5G technology, courtesy of EngineeringTV:
While iGR expects the overall cost of operating LTE networks to increase, the operating costs per gigabyte will actually decline, thanks to more efficient core networks. This is largely due to the shift toward more efficient fronthaul and backhaul, such as virtualized radio access network (vRAN) and Cloud-RAN (C-RAN) technologies. The C-RAN concept, for instance, connects a large number of distributed radio receivers to a centralized baseband unit (BBU) pool, providing high-bandwidth and low-latency communications.
Several LTE-A features in the early stages of deployment and testing are expected to have a significant role in 5G communications, according to the 4G Americas, a standards group that supports LTE evolution. These include eICIC capabilities; self-organizing network (SON) functions; and coordinated multi-point (CoMP) transmission, for improving data rates and lowering latency at the network edge.
The research into advanced 4G LTE functions provides a glimpse into the nature of 5G communications. “If 5G is in its research stage now in terms of radio,” explains Phil Twist, vice president of networks marketing at Nokia, talking about the LTE standard, “it is well beyond the research phase in terms of the network architecture and how you would need to build networks."