Distributed Time Slot Allocation in Ad Hoc Wireless Networks
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Solution Overview
Problem
Centralized time slot allocation in ad hoc wireless communication networks is inefficient due to the need for extensive network management information exchange, which consumes valuable bandwidth and is problematic in mobile multi-hopping networks with frequently changing topologies, where not all routes can support the quality of service (QoS) requirements of data streams.
Innovation Solution
A distributed method for time slot allocation is implemented, where nodes maintain a Local Communication Map (LCM) and use scouting messages to determine available time slots that meet QoS requirements, allowing for dynamic allocation and de-allocation of slots to maximize spatial reuse and adapt to topology changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centralized time slot allocation is used, then time slot allocation can be managed systematically, but extensive network management information exchange is required which consumes valuable bandwidth
Solution Approach 1:
The patent segments the centralized time slot allocation function into distributed components at each node. Each node independently manages its own time slot allocations and makes decisions based on local information, eliminating the need for extensive centralized coordination and reducing bandwidth consumption for management information exchange.
Solution Approach 2:
Each node in the ad hoc network performs self-service by autonomously allocating and managing its own time slots based on local communication maps and QoS requirements. This self-service approach eliminates dependency on centralized control and reduces the overhead of network-wide information exchange.
2Reliability
If centralized time slot allocation is used, then allocation decisions can be made centrally, but information propagation from periphery nodes to central node and back takes significant time
Solution Approach 1:
The patent divides the network into autonomous node segments that make allocation decisions locally without waiting for centralized coordination. This segmentation eliminates the time required for information to propagate across the entire network to a central node and back, as each node operates independently based on local information.
Solution Approach 2:
Nodes maintain local communication maps that are continuously updated with network topology and QoS information. This preliminary action of maintaining up-to-date local information enables nodes to make immediate allocation decisions without waiting for centralized coordination, reducing information propagation time.
3Reliability
If centralized time slot allocation is used, then all nodes can be reached through a central authority, but the technique is inefficient for mobile multi-hopping networks with frequently changing topologies
Solution Approach 1:
The patent implements dynamic time slot allocation where each node continuously updates its local communication map based on changing network topology. This dynamic approach allows the system to adapt to mobile multi-hopping networks with frequently changing topologies, as nodes can reconfigure their allocations in real-time without relying on centralized control that would be inefficient in such environments.
4Loss of energy
If distributed time slot allocation is used, then bandwidth consumption is reduced and adaptability to topology changes is improved, but nodes must independently determine available slots meeting QoS requirements
Solution Approach 1:
Nodes perform preliminary actions by continuously maintaining updated local communication maps that contain information about network topology, neighbor nodes, and QoS requirements. This preliminary preparation of local information reduces the complexity of slot determination, as nodes can make allocation decisions based on pre-collected local data rather than complex real-time calculations.
Solution Approach 2:
The patent implements feedback mechanisms where nodes exchange information about their local communication maps and QoS requirements with neighboring nodes. This feedback allows nodes to independently determine available slots meeting QoS requirements by using information from the network, reducing the complexity of local determination while maintaining distributed operation.
Data Source
AI summary
In a network comprising a source, a destination, and intermediate nodes along a route between the source and the destination, techniques are provided for allocating one or more time slots to transmit a particular data stream along the route based on the QoS requirements to transmit the particular data stream. In one implementation, a Scout Request message (SRM) is sent from the source to the destination to allocate time slots along the route to transmit a particular data stream to the destination. The SRM can include QoS requirements to transmit the particular data stream. Each intermediate node along the route can allocate one or more time slots to transmit the particular data stream based on the QoS requirements needed to transmit the particular data stream along the route.