Single band requirements

Description

Single band requirements are a set of RF performance criteria defined in 3GPP TS 37.105 and TS 37.145 for base station (BS) and user equipment (UE) operating in a single frequency band. These requirements set the minimum acceptable performance levels for key parameters such as output power, frequency error, unwanted emissions, blocking, and intermodulation. They are the foundation for ensuring that devices can operate reliably in a specific band without considering the complexities of multi-band operation, such as carrier aggregation or dual connectivity.

The architecture of these requirements revolves around the concept of an 'operating band,' which is a designated frequency range (e.g., Band 1, Band 3) with specific duplexing (FDD or TDD) and channel bandwidths. Single band requirements are defined for each operating band independently. They assume no exclusion bands—that is, the entire band is available for operation—and they do not include multi-band provisions like inter-band carrier aggregation. The requirements are typically expressed as limits, such as maximum allowed spurious emissions or minimum receiver sensitivity, and are verified through conducted or radiated test procedures.

Key components of single band requirements include transmitter characteristics (e.g., maximum output power, power control accuracy, spectrum emission mask), receiver characteristics (e.g., reference sensitivity, blocking characteristics), and performance requirements (e.g., throughput, demodulation). These are specified for both BS and UE, with different classes (e.g., wide area BS, local area BS) and power classes. The specifications TS 37.105 and TS 37.145 are part of the 3GPP TSG RAN WG4 series, which deals with radio performance and protocol aspects.

In the network, single band requirements play a crucial role in ensuring that devices from different vendors can interoperate and that they meet regulatory requirements for spectrum usage. They are used by manufacturers during design and testing, by network operators when deploying equipment, and by regulators when certifying devices. Without these baseline requirements, the deployment of cellular networks would be chaotic, with frequent interference and poor performance.

The evolution of single band requirements has been gradual, reflecting the introduction of new bands and technologies. The terminological definition itself has remained unchanged from Rel-13 through Rel-19, indicating that the fundamental concept is stable. However, the specific numerical requirements and test cases have been updated with each release to accommodate new frequency bands, higher bandwidths, and advanced features like massive MIMO. The term continues to be relevant as a building block for more complex multi-band scenarios.

Purpose & Motivation

Single band requirements exist to provide a clear, unambiguous baseline for RF performance when a device operates in a single frequency band. Before the formalization of such requirements, early cellular systems had varied performance expectations, leading to interoperability issues and inefficient spectrum use. The problem was that without a common set of requirements, a device certified in one network might cause interference or perform poorly in another, even within the same band.

The motivation for these requirements came from the need for global harmonization of spectrum and the desire to enable roaming and multi-vendor deployments. As cellular technology evolved from 2G to 3G to 4G and now 5G, the number of frequency bands increased dramatically, and each band needed its own set of performance criteria. Single band requirements provide a modular approach: first define requirements for each band individually, then build multi-band requirements by combining them with additional provisions.

Historically, the introduction of single band requirements in Rel-13 coincided with the maturation of LTE-Advanced and the beginning of 5G studies. The specifications TS 37.105 and TS 37.145 were created to consolidate requirements for multi-standard radio (MSR) and active antenna systems (AAS). The term 'single band requirements' was introduced to distinguish from 'multi-band requirements,' which include exclusion bands and other multi-band provisions. This distinction is important because multi-band operation introduces new challenges such as inter-band interference and the need for coordinated resource allocation. Single band requirements serve as the foundation upon which multi-band requirements are built, ensuring that even in complex multi-band scenarios, each band still meets its individual performance targets.