Dynamic Frequency Allocation for Mobile Ad Hoc Network Latency
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Solution Overview
Problem
Existing multiple access methods in mobile ad-hoc networks, such as TDMA, FDMA, and CDMA, face challenges including latency, reduced bandwidth due to guard times/bands, and the 'near-far effect, which hinder efficient high-speed data transmission and dynamic resource allocation in mobile ad-hoc networks.
Innovation Solution
A CDMA-based multiple access method that allocates distinct reception frequency bands to each node, uses asynchronous codes to minimize interference, and implements a dynamic frequency allocation algorithm to reuse frequency bands, ensuring efficient resource sharing and reducing latency through synchronous handover mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If TDMA multiple access method is used, then time segments are allocated to users, but transmission latency increases and medium access time is constrained
Solution Approach 1:
The patent implements dynamic frequency band allocation where nodes can switch between different frequency bands based on real-time network conditions and topology changes. This dynamic adaptation allows the system to optimize resource allocation without fixed time segments, reducing latency while maintaining efficient medium access.
Solution Approach 2:
The patent divides the frequency spectrum into multiple bands and allocates different bands to different nodes simultaneously. This segmentation of frequency resources allows multiple nodes to transmit at the same time without interference, eliminating the need for time segments and reducing transmission latency.
2Reliability
If guard time is introduced between time segments, then interference between users is prevented, but available bandwidth is reduced
Solution Approach 1:
The patent segments the frequency spectrum into multiple bands and assigns different bands to different nodes. This allows simultaneous transmission without requiring guard time, as the frequency separation naturally prevents interference between concurrent transmissions.
Solution Approach 2:
The patent transitions from time-based separation (TDMA) to frequency-based separation (FDMA/CDMA), adding a frequency dimension to the resource allocation. This dimensional change eliminates the need for guard time while maintaining interference prevention, thereby preserving full bandwidth availability.
3Reliability
If guard bands are introduced between frequency bands, then interference between users is prevented, but available bandwidth is reduced
Solution Approach 1:
The patent uses frequency band segmentation to allocate distinct bands to different nodes. By carefully selecting non-overlapping frequency bands, the system prevents interference without requiring additional guard bands, thus maximizing the utilization of available bandwidth.
4Adaptability or versatility
If CDMA access method is used, then all users can communicate on the same frequency, but the near-far effect saturates closer terminals
Solution Approach 1:
The patent implements dynamic frequency band allocation where nodes can switch between different frequency bands based on real-time network conditions. This dynamic adaptation allows the system to optimize resource allocation and mitigate the near-far effect by assigning appropriate frequency bands to different nodes based on their relative positions and transmission requirements.
Solution Approach 2:
The patent assigns different frequency bands to different nodes based on their specific communication requirements and relative positions. This localized frequency allocation strategy ensures that nodes experiencing the near-far effect are assigned frequency bands that minimize interference from closer terminals, thereby maintaining communication quality.
5Power
If directional antennas are used, then directivity gain is increased, but spatial reuse of frequency bands is limited
Solution Approach 1:
The patent implements dynamic frequency band allocation that adapts to the network topology and node positions. This dynamic allocation allows the system to optimize frequency band assignment based on real-time conditions, enabling better spatial reuse of frequency bands while maintaining the directivity gain from directional antennas.
Data Source
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AI summary
The invention relates to a method for multiple access to radio resources in a mobile ad hoc network comprising a plurality of mobile communicating terminals or nodes Ni, Nj, Nk, Nl, with known geographical coordinates, characterised in that said method comprises at least the following steps: a step of setting up said network; a step of allocating reception frequency bands B0, B1, B2, Bn to each one of said active nodes of said network, said frequency bands B0, B1, B2, Bn having identical bandwidths and being separated by a predetermined minimum guard band dB; a step of allocating a spreading code performed by each one of said active receiving nodes Ni of said network for each one of said adjacent transmitting nodes Nj, Nk, Nl to which the former is directly connected by an active link according to an asynchronous CDMA method; a power-management step performed by each one of said receiver nodes Ni of said network for each one of said adjacent transmitting nodes Nj, Nk, Nl to which the former is directly connected by an active link.