SDR: the next big thing?

How can cost savings, resource efficiency, and flexible management be achieved at the same time in the RAN department? Our solution is the SatSite base station, because of the solution chosen to build it, software-defined radio (SDR).

SDR systems can accurately be catalogued as ‘software-defined’ if they run on general purpose hardware, in a context where many existing technologies define themselves as SDR while running on special-purpose equipment.

With the adoption of more demanding technologies such as LTE, operators need to handle more traffic and deliver higher quality, meaning that mobile infrastructure needs to be run more efficiently and more profitably.

The reason for turning to SDR is the inflexibility of special-purpose hardware and software currently used in conventional base stations and what this entails in terms of costs, power consumption, and equipment.

Because they are physically larger, base stations using conventional DSPs are more difficult to manage. What’s more, DSP boards can’t be modified to perform new functions or improve existing ones, so extending the RAN infrastructure usually requires new equipment to be added, leading to increased capital investment. Used on commodity hardware, SDR systems have lower manufacturing costs, making them more profitable when compared to the current heavy, static network equipment.

Software Defined Radio (SDR) advantages compared to the conventional, DSP-based Radio Access Network equipments

Conventional BTS issue no. 1: increased power consumption

Special-purpose hardware products designed to perform complex functions come with high power demands. SDR allows more functions to be added to the same board, leading to the use of smaller equipment, with a lower power consumption.

Conventional BTS issue no. 2: limiting operators to a particular vendor

Another disadvantage of special-purpose equipment is that it is usually produced, serviced and supported by a particular vendor. In this case, operators are limited in recurring to different suppliers, as new equipment needs to inter-work with existing set-ups. SDR has the advantage of running on commodity hardware to avoid the use of specialized components and allow more flexibility to reconfigure or repurpose the hardware.

Conventional BTS issue no. 3: dedicated staff training

Specialized hardware/software usually comes with specific vendor training and support. SDR offers operators more autonomy in configuring and managing base station equipment, relying entirely on their personnel.

SDR allows a high level of flexibility in designing and managing the RAN, with network functions being upgraded or reprogrammed with the simple use of software. While it is not a new concept, most base stations continue to use chip sets like DSPs, which are built on special purpose hardware, keeping equipment heavy, costly, and inflexible for changing traffic needs.

SDR is essential for the expansion of mixed networks to provide access across multiple technologies, such as 2G/4G, and prioritize service allocation depending on the needs. SatSite base station simultaneously provides 2G and 4G coverage using from the same equipment.

Built on general purpose hardware and using a non-proprietary operating system, the SatSite allows operators to build smaller cell towers, with lower costs. SatSite cell sites can be suitably disposed to match the traffic needs in any area, and network performance can be improved remotely and easily, with a simple software change.

The SatSite uses a high level language which enables it to support more complex functions than a conventional base station using a DSP. In highly populated areas or situations, increasing the network capacity to serve more subscribers usually requires a higher density of cell towers. SatSite can be dynamically reprogrammed to meet higher subscribers capacities by a software configuration for multiple-TRX.

Due to the flexibility, capacity, power and cost efficiency SDR brings to mobile networks design, its future probably holds good news.

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