LTE Random Access Power Control with Preamble Format Offset
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current random access procedures in LTE networks face inefficiencies due to coarse open-loop power control, leading to potential collisions and failed access attempts, especially in varying interference levels and different cell scenarios, as they do not adequately account for preamble formats and signal-to-noise ratios.
Innovation Solution
The method involves determining a desired random access reception power based on configuration parameters, such as preamble format, and adjusting the random access transmission power using a preamble format-dependent correction term to optimize detection performance, thereby adapting the power setting to individual preamble formats and improving the efficiency of the random access procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If open-loop power control is used for random access transmission, then the power control mechanism is simple, but the power control precision is coarse and cannot adapt to varying interference levels and different cell scenarios
Solution Approach 1:
The patent applies dynamics by making the power control mechanism adaptive rather than static. The base station dynamically determines a power offset value based on current interference conditions and cell characteristics, and this offset is adjusted according to different preamble formats. This allows the system to adapt to varying interference levels and different cell scenarios while maintaining relative simplicity through centralized control at the base station.
Solution Approach 2:
The patent changes the power control parameter by introducing a power offset value that is added to the open-loop power control calculation. This offset parameter is determined by the base station based on interference conditions and is specific to different preamble formats. By changing this parameter dynamically, the system achieves finer power control precision without fundamentally changing the open-loop power control mechanism.
2Reliability
If power ramping is applied to overcome open-loop power control limitations, then the random access success rate improves, but the transmission time and number of attempts increases
Solution Approach 1:
The patent applies preliminary action by having the base station pre-determine and signal the power offset value to the UE before the random access transmission. This allows the UE to calculate the appropriate transmit power in advance with higher accuracy, reducing the need for multiple power ramping attempts. The base station performs preliminary assessment of interference conditions and determines the optimal offset before the UE transmits the random access preamble.
Solution Approach 2:
The patent implements feedback by having the base station determine the power offset based on measured interference conditions and cell characteristics, then signal this offset to the UE. The base station uses feedback from the random access procedure outcomes and interference measurements to adjust the power offset values for different preamble formats, creating a closed-loop system that improves success rate while controlling transmission time.
3Ease of operation
If a fixed power level is used for random access transmission, then the transmission power setting is simple, but the detection performance varies significantly across different preamble formats and interference conditions
Solution Approach 1:
The patent applies local quality by determining different power offset values for different preamble formats based on their specific detection requirements. Each preamble format receives a tailored power offset that is optimized for its characteristics and the current interference conditions. This allows the system to maintain simple operation through automated base station control while achieving high detection performance through format-specific power adjustments.
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A user equipment (10) arranged to be comprised in a Long Term Evolution network comprises a receiver configured to receive data from a base station (20) on a radio channel indicating a random access reception power to detect a random access transmission. The user equipment (10) further comprises a transmitter configured to transmit random access data using a random access transmission power, wherein the random access transmission power to be used is based on the received data, a parameter of random access configuration that influences a detection performance of the random access at the base station (20), which parameter comprises a preamble format and/or a basic cyclic shift value of a preamble, a power ramping arranged to increase the random access transmission power based on a transmission attempt number, and also to take into account power path loss between the user equipment (10) and the base station (20).