Multi-hop wireless backhaul network and method

Abstract

Some embodiments of the invention provide an implementation for a multi-hop wireless backhaul network. These embodiments can advantageously be deployed in dense urban areas and / or co-located with wireless access nodes, such as base-stations of a cellular wireless communication system. Preferably wireless links between constituent network nodes are set-up hierarchically. A basic result of this is that peer-to-peer (child-to-child) communication is generally prohibited and circuits are forced to conform to a topology. The multi-hop wireless backhaul network may be used to carry delay sensitive, high-density last mile circuit traffic over Non-Line-Of-Sight (NLOS) broadband radio links. Moreover, some embodiments of the invention provide a method of path-healing for re-routing of circuit traffic from circuits that have experienced catastrophic failures.

Description

RELATED APPLICATIONS[0001]This application is a divisional application of U.S. application Ser. No. 10 / 747,942 filed on Dec. 31, 2003 and claims the benefit thereof.FIELD OF THE INVENTION[0002]This invention relates generally to communication systems and, in particular, to backhaul networks.BACKGROUND[0003]Backhaul networks serve to efficiently transport large amounts of data across and between communication systems. The data carried in a backhaul network typically originates from (or is destined to) multiple sources in one geographic area and is destined for (or originates from) multiple other sources located in other geographic areas. As such, a backhaul network must provide aggregation points for data in each geographic area and efficiently transport aggregations of data between different geographic areas.[0004]Knowledge about the ultimate destinations (e.g. particular end-user devices, web-servers, etc.) of data is not required since backhaul networks do not provide direct acces...

AI Technical Summary

Benefits of technology

The invention is a multi-hop wireless backhaul network that provides a hierarchical topology of active wireless connections between a network access node and base nodes or access network nodes. The network adapts to establish virtual circuits with allocated bandwidth for delay-sensitive traffic, and can adapt to failures or changes in network conditions. The network can also adapt to dynamically allocate bandwidth to each active connection. The technical effects of the invention include improved network reliability, improved network performance, and improved network flexibility.

Problems solved by technology

Each of these technologies has a number of flaws that make deployment restrictive and expensive in dense urban areas.

Wireline and optical links require the expensive installation of a physical medium (e.g. twisted pair copper lines, optical fibers, etc.) to carry signals between backhaul network nodes.

In dense urban areas, where real estate is relatively expensive and the disruption of daily life is unwelcome, the placement of supporting equipment and the physical medium is a problem that network planners and operators would like to avoid.

Wireline and optical links become even less cost-effective for the amount of capacity provided beyond 3 to 4 T1's of capacity.

However, PTP microwave based systems are more expensive to integrate into wireless access systems (e.g. cellular wireless networks).

The absolute LOS requirement is an impractical requirement in dense urban areas.

The need for a dedicated frequency channel for each communication link introduces a number of problems discussed below.

Consequently, PTP microwave based systems are difficult to expand because frequency assignments must be adjusted and new radio equipment added to existing backhaul network nodes every time there is a requirement to increase capacity.

In fact, employing PMP broadcast radios actually enforces a less flexible network topology than the use of PTP links in that PMP broadcast radios do not easily lend themselves to circuit emulation and typically do not provide very high capacity.

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