Broadband local area network

What is this patent about?

’450 is related to the field of broadband local area networking over existing in-home coaxial cable infrastructure. Traditional home cable networks are designed for downstream delivery from a point-of-entry to various terminals, often utilizing passive splitters that create high isolation between devices. This architecture typically prevents direct peer-to-peer communication between consumer electronics, as signals cannot easily traverse splitters to reach other nodes. The invention addresses the need for a high-speed data network that can coexist with existing cable or satellite services while overcoming the signal degradation and multipath interference inherent in non-terminated, dispersive coaxial environments.

The underlying idea behind ’450 is the implementation of a dynamic, mesh-like network that treats every connection between two nodes as a unique, asymmetric communication channel. Rather than using a one-size-fits-all transmission profile, the system employs adaptive bit-loading within an Orthogonal Frequency Division Multiplexing (OFDM) framework. By periodically probing the physical link between specific pairs of modems, the system identifies frequency-specific notches and interference, then optimizes the modulation constellation for each subcarrier to maximize throughput. This allows the network to maintain high data rates even across low-quality cabling and passive splitters that would otherwise stifle standard broadband signals.

The claims of ’450 focus on a coordinated network architecture where a designated network controller manages admission, timing, and optimized transmission parameters for all participating modems. The independent claims specifically cover a mechanism where the controller probes slave modems to determine individual channel characteristics and then calculates a common bit-loaded modulation scheme for broadcast traffic. This ensures that a single broadcast transmission is optimized to be decodable by all target nodes simultaneously. Furthermore, the claims define a hybrid access model that supports both best effort packet delivery for general data and reserved communications for high-priority, constant-bit-rate streams like high-definition video.

In practice, the invention functions by establishing a network controller from the first modem activated on the line, which then manages a TDMA/TDD schedule to prevent signal collisions. When new devices join, they undergo an automated admission process that includes a handshake to characterize the link's echo and multipath profile. The system dynamically adjusts transmit power control on a per-link basis, ensuring that nodes in close proximity do not create unnecessary interference for distant nodes. This localized power management allows the network to operate at peak efficiency without disrupting legacy cable television or satellite signals sharing the same medium.

This approach differs from prior solutions by moving away from the assumption that a home coaxial network is a simple, transparent bus. By acknowledging the highly dispersive environment caused by splitters and reflections, the invention replaces static modulation with a continuously adapting physical layer. Unlike standard Ethernet or early coax-networking attempts, this system specifically solves the 'splitter jump' problem through its ability to calculate a common denominator for multicast groups. This ensures that even when different rooms have vastly different signal qualities, the network can still deliver synchronized multimedia content across the entire household reliably.