HK1173277A - Wireless communication node, method and system for utilizing smart antenna for establishing a backhaul network - Google Patents

Abstract

A wireless communication system for utilizing at least one smart antenna for establishing a backhaul network, a wireless communication node for use in a wireless communication system, and a method for utilizing smart antennas in a wireless communication system comprising a plurality of nodes are disclosed. A wireless communication system includes a plurality of nodes, and each node is capable of being connected to each other node. At least a portion of the nodes are provided with a smart antenna configured to generate a plurality of directional beams. Each node maintains a list of other nodes and beam configuration information to be used in transmission of messages to other nodes. When a source node is required to transmit to a target node, the source node retrieves the beam configuration information and transmits with a directional beam directed to the target node.

Description

Method and system for establishing backhaul network by using intelligent antenna and wireless communication node

The application is a divisional application of Chinese patent application with the application number of 200580018987.9, the application date of 2005, 6 and 7, and the name of method and system for establishing a backhaul network by using a smart antenna.

Technical Field

The present invention relates to wireless communications, and more particularly, to a method and system for establishing a backhaul network using a smart antenna, and a wireless communication node.

Background

One of the most important issues in wireless communication systems is to increase system capacity by reducing interference, and array antennas (also called smart antennas) have been developed to improve capacity and reduce interference. Smart antennas use multiple antenna elements to generate directional beams that transmit signals only to a specific azimuth. With smart antennas, wireless communication systems can increase capacity and reduce interference because signals are transmitted to a narrow area within the coverage area. Overall system capacity is increased because the transmitter may increase the transmission power level of the directed beam without causing excessive interference to other transmitters or receivers, such as wireless transmit/receive units (WTRUs) and base stations.

A wireless communication system generally includes a plurality of nodes, such as base stations and radio network controllers, etc., which are typically wired to each other, such as mesh networks or cellular networks, and which communicate with each other and transmit messages, such as backhaul messages.

However, the disadvantage of wired connections to establish a backhaul network is that they are too expensive, time consuming, and inflexible with respect to network changes or modifications. In particular, mesh networks must require nodes to be connected to each other, and when a new node joins the mesh network, it is a significant burden (in terms of cost and time) to establish a new connection to the new node for the backhaul.

There is therefore a need for a cost effective, less time consuming and resilient method and system for establishing a backhaul network.

Disclosure of Invention

The invention relates to a device and a system for establishing a backhaul network by using a smart antenna. The present invention directly uses smart antennas to improve intra-cell communication, increase throughput, and form at least a portion of a flexible backhaul network for communicating backhaul data. The present invention is for use in a wireless communication system including a plurality of nodes, wherein each node is connected together in a mesh network, at least a portion of the nodes providing one or more smart antennas configured to generate a plurality of directional beams, each node having one or more smart antennas maintaining a list including other nodes having smart antennas, beam directions, and configuration information for transmitting messages to the other nodes. When a source node needs to transmit backhaul data to a target node, the source node retrieves the beam direction and configuration information of the target node and transmits the message with a pointing beam pointing to the target node.

The present invention provides a system for establishing a backhaul network using at least one smart antenna, the system comprising: a plurality of nodes, each node connected to at least one neighboring node, each node comprising: a smart antenna configured to generate a plurality of directional beams; a memory configured to store a neighbor node list having link and beam configuration information for transmitting messages to the neighbor nodes; and a controller configured to: updating the list stored in the memory by monitoring signals received from the neighboring node and determining a configuration for transmitting data to the neighboring node; and selecting a particular directional beam for transmitting a particular message to another node using the updated list stored in the memory, at least one of the plurality of nodes being a hybrid node further comprising a wired backhaul connection to a core network.

The present invention also provides a wireless communication node for use in a wireless communication system, the wireless communication node comprising: a smart antenna configured to generate a plurality of directional beams; a memory configured to store a list of neighboring nodes and beam configuration information for transmitting messages to the neighboring nodes; and a controller configured to: updating the list stored in the memory by monitoring signals received from the neighboring node and determining an optimal configuration for transmitting data to the neighboring node; and selecting a particular pointing beam for transmitting a particular message to another node using the updated list stored in the memory to establish a backhaul network.

The present invention also provides a method of using a smart antenna in a wireless communication system including a plurality of nodes, wherein each of at least two of the plurality of nodes has a smart antenna generating at least one directional beam for connection to at least one neighboring node, the method comprising: each node transmits a beacon signal carrying a beacon message to neighboring nodes, wherein the beacon message comprises configuration information; measuring and storing a list of neighboring nodes having link and beam directions and configuration information for transmitting messages to the neighboring nodes; generating a directional beam for transmitting a specific message to a target node according to the beam direction and configuration information; and transmitting the message to the target node using the generated pointing beam.

Drawings

FIG. 1 is a block diagram of a network of nodes according to the present invention;

FIG. 2 is a block diagram illustrating the fabrication of a node according to the present invention;

FIG. 3 is a flowchart of a process for transmitting messages between nodes using smart antennas in accordance with the present invention; and

fig. 4 is an exemplary diagram of a beam pattern generated by a node in accordance with the present invention.

Detailed Description

The present invention is applicable to any wireless communication system including, but not limited to, Time Division Duplex (TDD), Frequency Division Duplex (FDD), and time division synchronous code division multiple access (TD-SCDMA), and is also applicable to Universal Mobile Telecommunications System (UMTS), CDMA 2000, CDMA in general, global system for mobile communications (GSM), integrated packet radio system (GPRS), and enhanced data rates for GSM evolution (EDGE).

The term "WTRU" as used herein includes, but is not limited to, a User Equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, or any other type of device capable of operating in a wireless environment. When referred to hereafter, the terminology "node B" includes but is not limited to a base station, a site controller, an access point, or any interfacing device in a wireless environment.

FIG. 1 is a block diagram of a network 100 of a plurality of nodes 102a-n according to the present invention. At least one of the nodes, shown as 102n, is connected to a core network 110. The operation of the core network of the wireless communication system is well known to those skilled in the art and is not the focus of the present invention, and therefore, the core network 110 will not be explained in detail herein.

Each node 102a-n serves one or more WTRUs (not shown) within the coverage area of the node 102a-n, and the network 110 may be a mesh network or a cellular network. In the description of the present invention, both mesh and cellular networks transmit backhaul information, but differ in that cellular networks typically have fixed network infrastructure and backhaul connections that are typically point-to-point connections and do not change, with one node transmitting backhaul data to another node at another location in the network and only to that location.

In mesh networks, the connections between nodes may change and therefore the backhaul data may be routed to different nodes at different times, especially in mesh networks, since the backhaul connections may change over time, it is important to be able to adapt the smart antenna so that it can be connected to different nodes without causing excessive interference to other nodes.

At least a portion of the nodes 102a-n provide at least one smart antenna (described in more detail below) and, in addition to general downloading to and uploading for reception by WTRUs, utilize the smart antenna to transmit backhaul data to other nodes 102a-n, the nodes 102a-n having the ability to generate multiple directional beams and steer the beams in azimuth.

The network 100 is expected to include nodes that are wired connections, as well as nodes that are wirelessly backhaul connected using smart antennas, thereby increasing the flexibility of the system since the connections established using smart antennas can be reconfigured and directed to different nodes. However, at least one node will have a wired connection to the core network 110 and a wireless connection to other nodes to provide a connection between the group of wireless nodes and the substantially wired core network, at least a portion of the nodes 102a-n also provide the ability to communicate backhaul information over wired or dedicated connections, and nodes having wired and wireless backhaul connections (102 n shown, hereinafter referred to as hybrid nodes) will be connected to the wired core network 110. In other words, when a node wirelessly transmits backhaul information with the help of a smart antenna, the backhaul information is eventually routed to the core network by the hybrid node 102n, so that the hybrid node 102n can receive and send backhaul information to the node via a wireless backhaul link, and also can receive and send backhaul information to the core network 110, thereby forming a bridge.

In one embodiment, the nodes 102a-n have a plurality of default beams 109a-h as shown in FIG. 4, and select one of the plurality of beams 109a-h to direct a transmission or reception. The eight directions shown in fig. 4 are beams, each of which may be generated by each node 102a-n, and it should be noted that the beams shown in fig. 4 are merely exemplary, and any number of beams, beam patterns, or any type of pattern may be implemented.

In another embodiment, each beam 109a-h may be generated and directed in real time without being picked from a predetermined set of locations.

The nodes 102a-n may dynamically or from a plurality of valid positions select the beam 109a-h direction, which provides the best performance in terms of system capacity, data throughput, interference, etc. The nodes 102a-n are typically fixed in a particular location so that once two nodes 102a-n have set a beam 109a-h and configuration, the orientation and configuration are stored and then available without modification. Because the wireless environment and traffic load may change over time, each node 102a-n needs to be able to provide more than one beam 109a-h to connect to other nodes 102a-n, so each node 102a-n monitors signals received from other nodes 102a-n to determine the wireless environment and dynamically adjusts the beam orientation and signal configuration to optimize system performance.

One embodiment of the operation of the system is as follows: a first selected node, e.g., node 102a, generates a beam and directs it toward other selected nodes, e.g., node 102b, by adjusting the composite weights for the antenna array elements, as is typically done with beamforming antenna arrays. At the same time, node 102a measures the quality of link a to node 102b, which may be measured by a signal-to-noise ratio, a bit or frame error rate, or other measure of quality indication. The transmitting node 102a finds the best antenna beam pointing, the best weight combination to maximize the link quality, and stores the link quality measurements and the corresponding beam pointing (weights). The transmitting node 102a does this for all neighboring nodes and stores the corresponding quality and beam information.

Any node 102a-n can be flexibly and wirelessly connected or disconnected from other nodes 102a-n by selecting one or more beams directed to the other nodes 102 a-n. In fig. 1, the first node 102a transmits messages to the second node 102B using a directional beam a and transmits messages to the fourth node 102d using a directional beam B, which are independently controlled and can transmit simultaneously, without causing excessive interference to other nodes 102a-n or WTRUs since each of the directional beam a and the directional beam B is only transmitted in a particular direction.

Fig. 2 is a block diagram of a node 202 according to the present invention. The node 202 includes a smart antenna 204, a controller 206, a memory 208, and an optional wired connection 210. The wired link 210 may be coupled to the core network 110 or other nodes. The node 202 performs a signal processing algorithm to accommodate user mobility, changes in the radio frequency environment, and multipath of common channel interference. A Radio Resource Management (RRM) function is performed by the controller 206 to determine how radio resources should be configured in the node 202.

Smart antenna 204 includes a plurality of antenna elements (not shown) that generate a plurality of directional beams under the control of controller 206, each beam serving as a wireless link between node 202 and other nodes, as described above, since node 202 is typically fixed in a particular location, the beam pointing directions and configurations between the two nodes can be predetermined and stored in memory 208. Memory 208 maintains a table containing other nodes, beam orientations, and configuration information for each other node, and when the node 202 needs to transmit messages to other nodes, such as backhaul data, the controller 206 retrieves the corresponding beam orientations and configuration information from the memory 208, generates a directed beam to direct to a particular direction, and transmits the message using the beam.

In the hybrid node 102n, this process is followed by establishing wireless links with other nodes with the help of the smart antenna 204. When the hybrid node 102n establishes a backhaul connection to the core network 110 or other nodes, no configuration information or beam selection is required because the wired connection 210 is physically fixed and always provides a connection between two nodes.

In accordance with the present invention, smart antenna 204 preferably has multi-beam capability, wherein each beam can be used independently, and a node 202 generates more than one directional beam to transmit backhaul data to multiple other nodes simultaneously. System capacity is also substantially increased because more than one directional beam may use the same frequency in the same coverage area.

Several nodes with several beams can be coupled together, which facilitates changing links and dynamically adapting to changes in the wireless environment. For example, two beams may be provided between two nodes for connection, and if one beam is subject to excessive interference, the node may switch to another beam to transmit a message.

The use of smart antennas makes the backhaul link between nodes flexible because each node is configured to generate multiple directional beams and direct the directional beams to any azimuth direction, so that when a new node is added to the network 100, existing nodes can establish a link to the new node by simply setting the new beam direction and configuring the new node, and in addition, when an existing node is removed from the network 100, the node can easily delete the beam pointing and configuration information of the removed node from the memory 208. The present invention enables the establishment or removal of connections between nodes without requiring additional equipment to be set up or removed, it being noted that the present invention can be implemented in a mesh network or a cellular network.

One strength of mesh networks is their ability to create new links and delete other links between nodes, which depends on a number of factors, including traffic load, interference and individual node performance. As shown in fig. 1, where multiple nodes 102a-n are coupled to each other using smart antennas, the lines between the nodes 102a-n in fig. 1 represent possible connections a-F, control may be centralized, whereby at least one node acts as a control node to control the connections between the nodes, or control may be distributed, whereby control may be distributed among several or all of the nodes. If a node is designated as a control node, the control node collects information about traffic conditions and performance of each node and determines a traffic route for optimal transmission of messages from one node to another.

Each node 102a-n preferably transmits one or more beacon signals in one or more of its beams, which provide information useful to the operation of the network. For example, the beacon signal may transmit the current power level, traffic level, interference level, and other parameters. The beacon signal may also include access, priority, security, identification, and other forms of access control and security control information. The beacon signal is periodically or aperiodically measured and the parameters are used as a basis for adjusting the connections between nodes to find the most efficient traffic route. The use of smart antennas in accordance with the present invention to form at least a portion of the wireless backhaul link allows flexibility in establishing and adjusting the link between nodes and reduces unnecessary costs.

For example, as shown in fig. 1, if the traffic load between the second node 102b and the fourth node 102s is too heavy, the other nodes can read the signals of the nodes 102b and 102d to know the traffic condition between the two nodes 102b and 102d, which will be described later. If the first node 102a wants to route traffic to the fifth node 102e, the second and fourth nodes 102b, 102d will be avoided, if applicable, and will be routed through the nth node 102N.

The present invention not only has the advantage of providing a flexible, wireless mesh network, but now also allows backhaul information (typically sent over a wireline) to be sent over the same flexible link through a smart antenna. The implementation of this dual-use smart antenna mechanism in accordance with the present invention is also a significant advantage over current wireless communication systems.

Fig. 3 is a flow diagram of a process 300 for inter-node message transmission using smart antennas in accordance with the present invention. At least some of the nodes provide at least one smart antenna configured to generate a plurality of directional beams and then independently direct the azimuth (step 302). Each beam serves as a wireless link to other nodes in addition to traffic normally downloaded to and uploaded by WTRUs. Each node maintains a list including other nodes and beam directions and configuration information for transmission to other nodes (step 304). It should be noted that steps 320 and 304 are typically performed according to a configured system or a reconfigured system to perform the actions of accepting or deleting nodes, and typically will not need to be performed under normal operation. When a source node needs to transmit to a target node, the source node retrieves the beam pointing and configuration information of the target node from memory and generates a pointing beam using the beam pointing and configuration information (step 306). Once a node is selected for transmitting backhaul data, the transmitting node selects the beam direction (weights) from the table and will use them on the antenna based on link quality and other considerations such as traffic density.

Since the environment may change, the procedures for measuring link quality and storing related information may need to be performed periodically, and beam pointing adjustments may also be necessary. The source node then transmits to the target node with the generated directional beam (step 308).

In an optional step, a network change may occur whereby a new node may be added to the network, an existing node may be removed from the network, or the radio frequency number or other state may be changed. To accommodate the changes, other nodes update the beam pointing and configuration information tables that reflect the changes (step 310).

Although the features and elements of the present invention are described in the embodiments in particular combinations, each feature or element can be used alone without the other features and elements or in various combinations with or without other features and elements of the present invention.

Claims (27)

1. A wireless communication system for using at least one smart antenna to establish a backhaul network, the system comprising:

a plurality of nodes, each node connected to at least one neighboring node, each node comprising:

a smart antenna configured to generate a plurality of directional beams;

a memory configured to store a neighbor node list having link and beam configuration information for transmitting messages to the neighbor nodes; and

a controller configured to:

updating the list stored in the memory by monitoring signals received from the neighboring node and determining a configuration for transmitting data to the neighboring node; and

using the updated list stored in the memory to select a particular pointing beam for transmitting a particular message to another node,

at least one of the plurality of nodes is a hybrid node that further includes a wired backhaul connection to a core network.

2. The system of claim 1, wherein the hybrid node further comprises a wired backhaul link connected to at least a neighboring node.

3. The system of claim 1, wherein the generated plurality of directional beams is selected from a set of predetermined locations.

4. The system of claim 1, wherein the generated plurality of pointing beams are dynamically selected and pointed in real-time.

5. The system of claim 1, wherein the directional beams are configured to provide optimal performance in terms of system capacity, data throughput, and interference.

6. The system of claim 1, wherein at least some of the nodes are configured to communicate backhaul information over the wired backhaul connection.

7. The system of claim 1, wherein the hybrid node is configured to receive and transmit backhaul information to another node over a wireless backhaul link while the hybrid node receives and transmits backhaul information to the core network.

8. The system of claim 1, wherein the plurality of nodes comprises a mesh network.

9. The system of claim 1, wherein the plurality of nodes comprise a cellular network.

10. A wireless communication node for use in a wireless communication system, the wireless communication node comprising:

a smart antenna configured to generate a plurality of directional beams;

a memory configured to store a list of neighboring nodes and beam configuration information for transmitting messages to the neighboring nodes; and

a controller configured to:

updating the list stored in the memory by monitoring signals received from the neighboring node and determining an optimal configuration for transmitting data to the neighboring node; and

selecting a particular pointing beam for transmitting a particular message to another node using the updated list stored in the memory to establish a backhaul network.

11. The wireless communication node of claim 10, further comprising a wired backhaul connection to a core network.

12. The wireless communication node of claim 11, wherein the node is configured to receive and transmit backhaul information to another node over a wireless backhaul link while the node receives and transmits backhaul information to the core network.

13. The wireless communication node of claim 10, further comprising a wired backhaul link connected to at least one other node.

14. The wireless communication node of claim 10, wherein the generated plurality of directional beams is selected from a set of predetermined locations.

15. The wireless communication node of claim 10, wherein the generated plurality of pointing beams are dynamically selected and pointed in real-time.

16. The wireless communication node of claim 15, wherein the directional beams are selected to provide optimal performance in terms of system capacity, data throughput, and interference.

17. The wireless communication node of claim 10, wherein the node is configured to communicate backhaul information over the wired backhaul connection.

18. The wireless communication node of claim 10 configured for use in a wireless mesh network.

19. The wireless communication node of claim 10 configured for use in a cellular network.

20. A method for using a smart antenna in a wireless communication system including a plurality of nodes, wherein each of at least two of the plurality of nodes has a smart antenna that generates at least one directional beam for connection to at least one neighboring node, the method comprising:

each node transmits a beacon signal carrying a beacon message to neighboring nodes, wherein the beacon message comprises configuration information;

measuring and storing a list of neighboring nodes having link and beam directions and configuration information for transmitting messages to the neighboring nodes;

generating a directional beam for transmitting a specific message to a target node according to the beam direction and configuration information; and

transmitting the message to the target node using the generated directional beam.

21. The method of claim 20, wherein each node is connected with a plurality of beams, whereby a beam is adaptively switched between beams provided for the junction.

22. The method of claim 20, further comprising the step of updating the list reflecting changes or modifications to the network.

23. The method of claim 20, further comprising the steps of obtaining information about traffic load conditions and capabilities of neighboring nodes and selecting an appropriate path for transmitting the message to another node based on the information.

24. The method of claim 20, wherein the plurality of nodes comprises a mesh network.

25. The method of claim 20, wherein the plurality of nodes comprise a cellular network.

26. The method according to claim 20, wherein one of the plurality of nodes is designed as a control node, and the control node collects information about traffic load situation and capabilities of each node and controls the determined path in each node.

27. The method of claim 20, wherein each node uses the beacon message to select an appropriate path for transmitting messages to other nodes.