Frequency Hopping Sub-band Allocation for Interference Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In communication systems using Frequency Division Multiple Access (FDMA) techniques, determining and signaling the appropriate frequency hopping scheme to user devices for efficient resource allocation is challenging, particularly in ensuring no collisions and minimizing inter-cell interference while maintaining frequency diversity and single carrier properties.
Innovation Solution
A communications node applies a frequency shift to initially allocated frequency resources using a pseudo-random frequency hopping sequence, defined by the equation y={x+a(t)N} mod NRB, where NRB is the total number of frequency resources, N is the number of contiguous resources in each sub-band, x is the initial resource, t is a time counter, and a(t) is an integer value, to determine frequency resources for communication, ensuring contiguous resource allocation and reducing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency hopping is implemented in FDMA systems, then frequency diversity and interference avoidance are improved, but signaling overhead and system complexity increase
Solution Approach 1:
The frequency spectrum is divided into multiple sub-bands, and frequency hopping is applied within these segmented regions. This segmentation allows controlled frequency diversity while reducing the complexity of managing complete spectrum hopping patterns.
Solution Approach 2:
The patent modifies the frequency allocation parameters by introducing sub-band based hopping patterns and adjusted frequency shift values. This changes the hopping behavior to achieve diversity without requiring complex signaling for every possible frequency transition.
2Object-affected harmful factors
If frequency hopping sequences are applied to allocate frequency resources, then inter-cell interference is reduced, but collision risk between users increases if not managed properly
Solution Approach 1:
Different frequency hopping patterns and shift values are assigned to different users within the same cell. This local differentiation ensures that while all users benefit from reduced inter-cell interference through coordinated hopping, individual users are assigned non-conflicting patterns that prevent collisions.
Solution Approach 2:
The system dynamically adjusts frequency allocations and hopping patterns based on user requirements and interference conditions. This dynamic adaptation allows the system to maintain low interference while avoiding collisions by adjusting patterns in real-time.
3Loss of energy
If frequency resources are allocated contiguously, then power amplifier efficiency is improved, but frequency diversity is reduced
Solution Approach 1:
The system implements periodic frequency hopping within contiguous resource blocks. This periodic action allows the system to maintain contiguous allocation for power efficiency during each hop cycle, while the periodic switching between different contiguous blocks provides the necessary frequency diversity over time.
Data Source
AI summary
A communications node operable to communicate with another communications node over a communications channel having a plurality of frequency resources, the communications node includes data defining a division of the communications channel into a plurality of contiguous sub-bands each having N frequency resources, wherein each frequency resource in a sub-band has a corresponding frequency resource in each of the other sub-bands, data defining an initial allocation of the frequency resources, a resource determination module operable to apply a frequency shift to the initially allocated frequency resources in accordance with a frequency hopping sequence to determine frequency resources to use for communicating information with the other communications node, wherein the frequency shift applied moves the initially allocated frequency resources to corresponding frequency resources in another sub-band, a transceiver for communicating information with the other communications node using the determined frequency resource.