Inter-sector Interference Control via Selective Power Attenuation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In frequency hopping OFDMA systems, inter-sector interference significantly degrades performance for disadvantaged users, particularly those at the edge of sectors, due to overlapping FH sequences with neighboring sectors, leading to increased interference and reduced data transmission power.
Innovation Solution
Implementing selective blanking or attenuation of transmit powers for interfering users in neighboring sectors by forming a blanking pattern based on the target user's FH sequence, allowing each sector to reduce or eliminate transmissions on specific subbands that collide with the target user's subbands, thereby minimizing inter-sector interference without requiring changes at the terminals or over-the-air signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pseudo-random FH sequences are used for each sector to randomize inter-sector interference, then the average interference is reduced, but disadvantaged users still experience high interference levels that significantly degrade performance
Solution Approach 1:
The patent applies local quality by making different sectors have different transmit power levels on specific subbands based on their impact on target users. Each sector identifies subbands that cause interference to target users in other sectors and reduces transmit power on those specific subbands, creating localized power adjustments rather than uniform power control across all subbands.
Solution Approach 2:
The patent changes the transmit power parameter selectively for interfering sectors on specific subbands where they cause interference to target users. By adjusting the power parameter locally rather than globally, the system reduces interference for disadvantaged users while maintaining overall system performance.
2Object-affected harmful factors
If transmit power is reduced for interfering users to reduce inter-sector interference, then interference for target users decreases, but overall system throughput and productivity are degraded
Solution Approach 1:
The patent applies local quality by making different sectors have different transmit power levels on specific subbands based on their impact on target users. Each sector identifies subbands that cause interference to target users in other sectors and reduces transmit power on those specific subbands, creating localized power adjustments rather than uniform power control across all subbands.
Solution Approach 2:
The patent applies partial action by reducing transmit power only on the specific subbands where interference occurs, rather than reducing power across all subbands. This partial power reduction is sufficient to protect target users while minimizing the impact on overall system throughput.
3Object-affected harmful factors
If selective blanking or attenuation is implemented for interfering transmissions, then inter-sector interference is reduced for target users, but the complexity of coordinating between sectors increases
Solution Approach 1:
The patent applies preliminary action by having each sector pre-identify the subbands on which they will reduce transmit power, based on information about target users in other sectors. This advance planning allows sectors to coordinate their interference reduction strategies without requiring complex real-time coordination during data transmission.
Solution Approach 2:
The patent uses feedback mechanisms where sectors share information about target users and their FH sequences with neighboring sectors. This feedback loop enables each sector to make informed decisions about which subbands to attenuate, reducing interference while maintaining system-wide coordination.
Data Source
AI summary
Inter-sector interference for a target user in a sector may be controlled by selectively blanking or attenuating transmit powers for interfering users in neighboring sectors whenever their transmissions collide. The sector provides the frequency hopping (FH) sequence or subband usage for the target user to the neighboring sectors. Each neighboring sector uses the target user's FH sequence to form a blanking pattern. Each neighboring sector then either blanks or reduces transmit power for each subband in its blanking pattern. Each user in each neighboring sector receives either (1) punctured symbols for subbands in the blanking pattern, if blanking is performed, or (2) lower energy symbols for these subbands, if attenuation is performed. In any case, the target user and each neighboring user may process their received symbols in the normal manner and do not need to be informed of the blanking/attenuation.