The research found that as much as 88% of an operators licensed spectrum was underutilized in enterprise campus buildings, while on upper floors of high rise buildings a mobile device could handover as many as 51 times, due to the constantly fluctuating signal strength between all the visible cell sites.
The results of the study reveal the limitations of serving in-building coverage primarily by an outdoor macro network and that coverage inside does not equate to sufficient capacity for an ever-growing demand for always-on broadband. With approximately 80 percent of all mobile voice and data traffic occurring indoors, the in-building mobile data user consumes a disproportionate amount of network resources, requiring the outdoor macro network to assign more resources relative to the outdoor mobile device for a given end-user data rate.
When operators attempt to use the outdoor macro network to provide in-building coverage and targeted capacity to a relatively small geographic area, this research shows that they are falling short. Their spectrum, which is their most valuable asset and in which theyve invested billions of dollars, is not only being under-utilized, in some indoor scenarios isnt being used at all, said Michael Thelander, CEO, Signals Research Group. However, while there are indoor coverage and capacity alternatives that give the user a range of ways to obtain connectivity, the outdoor user has no other means. It is the RAN or nothing. So, by shifting the in-building mobile voice and data traffic on to an in-building solution, not only is in-building coverage and capacity improved but there is also a direct impact on the capacity of the outdoor macro network.
The construction materials used in a building were also found to have a direct impact on indoor coverage. Signals Research Group found that an unintended consequence of material designed to be more energy efficient was that it was also very effective at blocking RF signals from the outside. The material is designed to keep sunlight out and control air temperature by absorbing large amounts of radiated signals. However, the RF signals from the outdoor macro RAN were also adversely affected.
A range of in-building scenarios were tested by Signals Research Group, including college and enterprise campuses, high-rise buildings, shopping malls, hotels and airports. Highlights of the research results include:
- Enterprise campus: The utilization of spectrum can vary immensely between buildings on a single campus site. While in some buildings 100% of available spectrum was used, SRG found that in other buildings the utilization rate was as low as just 12%. The combination of lack of an in-building solution and the construction materials used in the building all affected the indoor coverage and capacity and this is despite the fact that one of the buildings housed over 500 employees and was the global HQ for a universally recognized brand.
- University campus: In performance tests conducted on a university campus, on average just 30% of the spectrum was utilized indoors. On some floors of the buildings that were tested there was extremely poor or non-existent coverage, while in other buildings it was nearly 100%. Capacity requirements compounded the issue due to the propensity of students with smartphones to consume large amounts of data in a concentrated indoor environment.
- High-rise building: Sometimes a building can also have too much coverage. High-rise buildings in particular can be exposed to a large number of visible cell sites, causing high interference level. Signals Research Group found that just walking around one floor of a high-rise building could require a mobile device to handover as many as 51 times, due to the constantly fluctuating signal strength between all the cells. This has a direct impact on the performance of the device, significantly impacting battery life. Furthermore, because the device is effectively always operating at the end of a constantly changing cell, throughput is affected in a way that is akin to the cell suffering from limited capacity. Users in a downtown high-rise environment therefore share network resources not only with outdoor users, but also with users in adjacent buildings.
- Hotels: While larger hotels sometimes have in-building solutions, the experience between hotels was marked. A San Francisco hotel had a spectrum utilization of just 38%, in contrast to a Dallas hotel, which hit 61% spectrum utilization.
Signals Research Group points out that Wi-Fi is not always an adequate alternative to in-building cellular coverage and capacity in the hospitality sector as an acceptable alternative for cellular voice. Voice over Wi-Fi mobility and throughput falls well below the threshold that signifies a good mobile data experience as soon as many users are congregated together and connected to the Wi-Fi service.
This research proves what peoples personal experience of having poor indoor coverage at work or network congestion at the shopping mall is already telling them the user experience of in-building coverage and capacity is at best mixed and at worst practically non-existent, said Ronny Haraldsvik, CMO, SpiderCloud Wireless. Not only that, but recent end-user research uncovered that over one third of senior IT managers would be likely to move to a wireless carrier that could guarantee better indoor mobile coverage and capacity. This makes for a coverage and capacity double-whammy. Not only is valuable spectrum being left underutilized, but it is also directly impacting the end-user experience and creating opportunities for subscriber churn.
Scalable Small Cell Systems for Enterprise Deployments by Mobile Operators
SpiderCloud is the first company to offer a true multi-mode access system with 3G, LTE/4G and dual-band Wi-Fi for reliable mobile services indoors for enterprise customers of any size, called an Enterprise Radio Access Network (E-RAN). The E-RAN system consists of a Services Node (SCSN) that can control over 100 self-organizing and multi-access 3G, Wi-Fi and LTE/4G small cells that can be installed in just days using an enterprise-Ethernet Local Area Network (LAN) as managed service by a mobile operators network. In addition to providing reliable coverage and capacity, the E-RAN with the Services Node includes an Applications Programming Interfaces (API). The API inside the Services Node provides trusted connections to the Radio Nodes and a logical view into all devices on the E-RAN, to enable secure services to any mobile device on the network.
The third-party performance analysis was conducted by Signals Research Group on behalf of SpiderCloud Wireless. The report is available by request from SpiderCloud Wireless.