UTRAN Position Radio Resource Management

Description

The UTRAN Position Radio Resource Management (U-PRRM) function is a specialized resource manager within the UTRAN positioning architecture, typically implemented in the Radio Network Controller (RNC). Its domain is the allocation and supervision of radio resources dedicated to positioning operations. When the U-PRCF coordinates a positioning procedure (e.g., an OTDOA session requiring reference signal transmission from multiple cells), it consults the U-PRRM to secure the required resources. The U-PRRM makes decisions on which physical resource blocks, time slots, or codes can be used for positioning reference signals (PRS). It manages the trade-off between positioning accuracy (which may require more resources) and the impact on capacity for user data traffic. The function handles potential conflicts, such as when positioning resource requests from multiple UEs or services overlap. It also manages resources for positioning-related signaling, such as measurement command and report messages on dedicated or common channels. By having a dedicated RRM entity for positioning, the network can implement sophisticated policies—for example, prioritizing emergency positioning requests over commercial LBS requests or dynamically adjusting positioning resource allocation based on overall cell load.

Purpose & Motivation

The U-PRRM was introduced to solve the critical problem of radio resource contention between positioning services and conventional voice/data services in UTRAN. Positioning activities, especially methods like OTDOA that require periodic reference signal transmission from multiple cells, consume valuable radio resources (power, bandwidth, codes). Without dedicated management, these activities could indiscriminately degrade network capacity and quality of service for other users. The U-PRRM provides a controlled, policy-based mechanism to allocate resources specifically for positioning. This ensures that location services, particularly mandated emergency services, can be guaranteed the necessary resources to meet accuracy and latency requirements, while minimizing negative impact on the broader network performance. Its creation reflects the evolution of cellular networks into multi-service platforms where resource management must be granular and service-aware. It addresses the limitations of earlier, more monolithic RRM approaches that were not designed to handle the specific, periodic, and measurement-intensive demands of advanced positioning technologies.

Key Features

• Allocates and manages radio resources (e.g., power, time slots, codes) for positioning signals and procedures
• Handles resource scheduling for Positioning Reference Signal (PRS) transmission in OTDOA
• Manages resources for positioning-related signaling channels and measurement reporting
• Implements policy-based prioritization (e.g., emergency vs. commercial positioning requests)
• Optimizes resource usage to balance positioning accuracy with overall cell traffic capacity
• Interfaces with the U-PRCF to grant or deny resource requests for specific positioning sessions

Evolution Across Releases

Defining Specifications