Bitmap-Based Fast-Feedback Channel Allocation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current IEEE 802.16 wireless communication systems face inefficiencies in fast-feedback channel allocation, leading to wasted bandwidth due to gaps in channel usage and high signaling overhead, particularly when devices intermittently require or stop requiring feedback channels.
Innovation Solution
The implementation of a bitmap-based method to dynamically allocate fast-feedback channels, where a bitmap is broadcast to devices indicating which channels to use, allowing each device to determine its channel allocation and enabling compact occupation of the fast-feedback region without gaps, thereby reducing signaling overhead and ensuring full channel utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If semi-dynamic fast-feedback channel allocation is used, then implementation simplicity is maintained, but bandwidth efficiency deteriorates due to gaps in channel usage
Solution Approach 1:
The patent implements dynamic fast-feedback channel allocation where the base station assigns specific fast-feedback channel indices to subscriber stations on a per-frame basis. This dynamic assignment eliminates gaps in channel usage by ensuring that all allocated channels are fully utilized, thereby improving bandwidth efficiency while maintaining implementation simplicity through centralized control.
Solution Approach 2:
The patent changes the allocation parameter from static/semi-dynamic to fully dynamic by introducing a bitmap-based allocation mechanism. The bitmap indicates which fast-feedback channels are assigned to which subscriber stations, allowing the system to adapt channel assignments to current traffic conditions and eliminate unused channels, thus improving bandwidth efficiency without complicating the implementation.
2Productivity
If index adjustment messages are transmitted frequently to avoid gaps, then channel utilization is improved, but signaling overhead increases
Solution Approach 1:
The patent applies preliminary action by having the base station pre-allocate fast-feedback channel indices to subscriber stations before they are needed. The bitmap-based allocation mechanism prepares channel assignments in advance, allowing subscriber stations to immediately use assigned channels without requiring frequent index adjustment messages, thus improving channel utilization while reducing signaling overhead.
Solution Approach 2:
The patent uses a bitmap representation to copy and transmit channel allocation information efficiently. Instead of transmitting individual index adjustment messages for each subscriber station, the system creates a compact bitmap copy of the allocation state and transmits it once, achieving full channel utilization information dissemination with minimal signaling overhead.
3Reliability
If fast-feedback channels are allocated for all devices, then feedback coverage is ensured, but bandwidth is wasted when devices do not require feedback
Solution Approach 1:
The patent applies local quality by allocating fast-feedback channels selectively to only those subscriber stations that currently require feedback. The bitmap-based allocation mechanism allows different parts of the system (different subscriber stations) to have different channel assignments based on their local needs, ensuring feedback coverage for active users while avoiding bandwidth waste for inactive users.
Solution Approach 2:
The patent implements dynamic channel allocation where the set of subscriber stations receiving fast-feedback channel assignments changes over time based on their feedback requirements. This dynamic approach ensures that feedback coverage is maintained for all stations that need it while automatically eliminating allocations for stations that don't require feedback, thereby preventing bandwidth waste.
Data Source
AI summary
A method includes allocating channels in a fast-feedback channel region for a plurality of devices, and transmitting to the plurality of devices at least one bitmap defining fast-feedback uplink channel allocations for individual ones of the plurality of devices. In one embodiment a plurality of bitmaps are transmitted, the plurality of bit maps together informing individual ones of the plurality of devices of permission to use none, one or more than one particular fast-feedback channel. In this case each bitmap includes a plurality n of bit positions corresponding to n indices, where each device is identified by an associated one of the n indices, and where a bit at an index value p in a first bitmap and a bit at the same index value p in a second bitmap, when concatenated together, equal a number of fast-feedback uplink channels that are allocated to a particular device associated with the index value p.