Dynamic Carrier Allocation for Cable TV Bandwidth Efficiency
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing community access television (CATV) systems face inefficiencies in bandwidth utilization, as each program channel is fixedly assigned to a limited number of carriers, limiting the number of channels that can be provided to subscribers, despite many channels being unused at any given time.
Innovation Solution
The system dynamically assigns carriers to only those program channels selected by subscribers, allowing for the addition or removal of channels based on demand, enabling more channels to be provided than the initial limited bandwidth allows, by using a controller to manage carrier allocation and send control messages to set-top terminals for tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If all program channels are simultaneously made available to each set-top terminal, then subscribers can access any channel, but the number of program channels cannot exceed the limited number of carriers M
Solution Approach 1:
The patent implements dynamic carrier assignment where carriers are not fixed to specific program channels but are dynamically allocated based on subscriber requests. The system transitions from a static allocation model (where each carrier is permanently assigned to one channel) to a dynamic model where the controller reassigns carriers in real-time according to demand, allowing the number of available channels to exceed the number of physical carriers.
Solution Approach 2:
Each carrier is designed to be universal and can carry program materials for any program channel depending on demand. Instead of dedicating specific carriers to specific channels, the system makes carriers multi-functional by allowing any carrier to transmit any channel's content when requested, thereby increasing channel capacity beyond the physical carrier limit.
2Adaptability or versatility
If the number of carriers is increased to provide more program channels, then more channels can be available, but the network bandwidth is limited and cannot accommodate more than M carriers
Solution Approach 1:
The system employs periodic reassignment of carriers to program channels based on demand patterns. Rather than maintaining permanent assignments, the controller periodically evaluates subscriber requests and reassigns carriers accordingly, allowing the same physical carriers to serve different channels at different times, thus providing more channel variety within the fixed bandwidth constraint.
Solution Approach 2:
The system changes the parameter of carrier assignment from fixed to variable. By making the carrier-channel assignment relationship changeable based on demand, the system can provide more than M channels through time-division multiplexing, where the same physical carriers are reused for different channels at different times, effectively increasing channel capacity without increasing bandwidth.
3Reliability
If carriers are fixedly assigned to program channels, then transmission is simple and reliable, but bandwidth is wasted when channels are not selected by subscribers
Solution Approach 1:
The system implements a demand-driven architecture where program materials are transmitted only when subscribers request them. Set-top terminals actively request the program materials they want to view, and the controller responds by assigning appropriate carriers and transmitting the requested content. This eliminates bandwidth waste by ensuring transmission only occurs when needed, while maintaining reliability through on-demand delivery.
Solution Approach 2:
The system uses feedback from subscriber requests to control carrier assignment and program material transmission. When a subscriber requests a channel, the controller receives this feedback and dynamically assigns a carrier to transmit the requested program materials. This feedback mechanism ensures that bandwidth is used efficiently by transmitting only the content that subscribers actually want to view.
Data Source
AI summary
In a cable television system in accordance with the invention, program materials are made available to subscribers in a neighborhood on an as needed basis. Specifically, when a subscriber at a set-top terminal selects a program channel to watch, the selection request is transmitted to a headend of the system. In response to such a request, a controller in the headend determines whether the material of the selected program channel has been made available to the neighborhood. If it has been made available, the controller identifies to the set-top terminal the carrier which is carrying the requested program material, and to which the set-top terminal tunes to obtain the requested program material. Otherwise, the controller assigns an unused carrier to carry the requested program material, and informs the set-top terminal of the identity of the newly assigned carrier. The controller also retires those carriers assigned for the program channels which are no longer watched by the subscribers in the neighborhood.