KR20120052203A - Method and system for utilizing smart antennas establishing a backhaul network - Google Patents

Abstract

PURPOSE: A backhaul network establishment method using a smart antenna and system thereof are provided to effectively reduce backhaul network establishment costs and time consumption by searching configuration information for a target node. CONSTITUTION: Smart antennas which generates plural directional beams are respectively provided to nodes(302). Beam directions and configuration information are stored in order to transmit message and lists of the nodes(304). The smart antenna generates the directional beams by using the beam direction and the configuration information(306). A source node transmits messages to a target node through the directional beams(308). Other nodes update the list of the configuration information and the beam direction(310).

Description

METHOD AND SYSTEM FOR UTILIZING SMART ANTENNAS ESTABLISHING A BACKHAUL NETWORK}

The present invention relates to wireless communications. More specifically, the present invention is a method and system for using a smart antenna in establishing a backhaul network.

One of the most important issues in wireless communication systems is to increase the capacity of the system by reducing interference. Array antennas (also known as smart antennas) have been developed to improve capacity and reduce interference. The smart antenna uses a plurality of antenna elements to generate a directional beam that emits signals only in a particular direction of azimuth, and selectively detects signals transmitted from the particular direction. In the case of a smart antenna, signals are radiated in a narrow area of the coverage area, thereby increasing the capacity of the wireless communication system and reducing interference. This increases the overall system capacity since the transmitter can increase the transmit power level of the directional beam without causing excessive interference to other transmitters and receivers, such as wireless transmit / receive units (WTRUs) and base stations.

A wireless communication system generally includes a number of nodes, such as a base station and a wireless network controller. Nodes are typically connected to each other in a wired connection such as a mesh network or a cellular network. The nodes communicate with each other and send a message, such as a backhaul message.

However, wired connections are expensive, time consuming, and inflexible to modifications or changes in the network, which is disadvantageous for wired connections in setting up a backhaul network. In particular, mesh networking requires nodes to be connected to each other. When a new node is added to the mesh network, it becomes a heavy burden (both in terms of cost and time) to establish a new connection to the new node for backhaul.

Therefore, there is a need for a cost-effective, less time-consuming, and flexible method and system for establishing a backhaul network.

The present invention is implemented in a wireless communication system including a plurality of nodes, each node being connected to each other in a mesh network. At least some of the nodes are provided with one or more smart antennas configured to generate multiple directional beams. Each node with one or more smart antennas maintains a list of other nodes with smart antennas and beam direction and configuration information to be used to send messages to these other nodes. When a source node is required to send backhaul data to the target node, the source node retrieves beam direction and configuration information for the target node and transmits a message with a directional beam towards the target node.

Through the present invention, a cost effective, less time consuming, and flexible wireless communication method and system for establishing a backhaul network can be implemented.

1 is a block diagram of a network of multiple nodes in accordance with the present invention.
2 is a block diagram of a node made in accordance with the present invention.
3 is a flow diagram of a process using a smart antenna in message transmission between nodes in accordance with the present invention.
4 is a diagram of an example of a beam pattern generated by a node in accordance with the present invention.

The present invention is a method and system for using a smart antenna in establishing a backhaul network. The present invention relates to the use of smart antennas internally to form at least a portion of a flexible backhaul network that improves in-cell communication, increases throughput, and carries backhaul data. The present invention is implemented in a wireless communication system including a plurality of nodes, each node being connected to each other in a mesh network. At least some of the nodes are provided with one or more smart antennas configured to generate multiple directional beams. Each node with one or more smart antennas maintains a list of other nodes with smart antennas and beam direction and configuration information to be used to send messages to these other nodes. When a source node is required to send backhaul data to the target node, the source node retrieves beam direction and configuration information for the target node and transmits a message with a directional beam towards the target node.

The present invention applies to time-division duplication applied to Universal Mobile Telecommunications System (UMTS), CDMA2000, generally CDMA, Global System for Mobile Communications (GSM), Universal Packet Radio System (GPRS), and Enhanced Data Rate (EDGE) for GSM evolution. (TDD), frequency division duplication (FDD), and time division sync code division multiple access (TD-SCDMA), but are not limited to any wireless communication system.

In the following, the term "WTRU" includes but is not limited to a user device, mobile station, fixed or mobile subscriber unit, pager, or any other type of device capable of operating in a wireless environment. As mentioned below, the term "node" includes, but is not limited to, a base station, a Node-B, a site controller, an access point, or any other type of interfacing device in a wireless environment.

1 is a block diagram of a network 100 of multiple nodes 102a-n in accordance with the present invention. At least one of the nodes (shown diagrammatically 102n) is connected to the core network 110. Operation of the core network of a wireless communication system is well known to those skilled in the art and is not central to the invention. Therefore, the core network 110 will not be described in detail.

Each node 102a-n serves one or more WTRUs (not shown) located within the coverage area of nodes 102a-n. The network 100 may be a mesh network or a cellular network. In the context of the present invention, both mesh networks and cellular networks transmit backhaul information, but there are fundamental differences. Cellular networks typically have a fixed network infrastructure and have backhaul connections. Such connections are typically point-to-point and they do not change. One node transmits backhaul data only to that other node in another location in the network.

In the case of a mesh network, the inter-node connections change, so the backhaul data can be sent to different nodes at different times for different routing. In particular, for mesh networks, since backhaul connections may change over time, it is important to adjust the smart antennas so that connections to different nodes can be made without creating unreasonable interference to other nodes.

At least some of the nodes 102a-n are provided with at least one smart antenna (which will be described in detail below), and in addition to the normal download transmission for the WTRU, for transmission of backhaul data to other nodes 102a-n. Uses a smart antenna and uploads the reception from the WTRU. These nodes 102a-n can generate multiple directional beams and steer the beam in any direction in azimuth.

The network 100 is expected to include nodes with wired connections as well as nodes with wireless backhaul connections, using smart antennas. Connections established using smart antennas are reconfigured and directed to different nodes, thus increasing the flexibility of the system. However, at least one of the nodes 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 an essentially wired core network. At least some of the nodes 102a-n may also be provided with the ability to transmit backhaul information via a wired or dedicated connection. Nodes with wired and wireless backhaul connections (shown as node 102n, referred to hereinafter as hybrid nodes) will be connections to wired core network 110. In other words, since the nodes wirelessly transmit backhaul information with the aid of a smart antenna, this backhaul information will eventually be routed through the hybrid node 102n to the core network 110. Therefore, the hybrid node 102n may receive the backhaul information and transmit it to nodes making a wireless backhaul connection, while receiving the backhaul information and transmitting it to the core network 110, thereby forming a bridge. can do.

In one embodiment, nodes 102a-n have a number of predetermined beams 109a-h, as shown in FIG. 4, and one of the plurality of beams 109a-h for directing transmission or reception. Select. 4 shows eight beams that can be generated by each node 102a-n at an azimuth angle. The beams shown in FIG. 4 are provided only as an example and any number of beams, beam patterns, or any type of pattern can be implemented.

In other embodiments, each beam 109a-h may be generated and directed in real time rather than selected from a set of positions.

Nodes 102a-n dynamically select the beam 109a-h direction that provides the best performance with respect to system capacity, data throughput, interference, and the like, or select from among a number of available locations. Nodes 102a-n are generally fixed at a particular location. Therefore, once the configuration and beams 109a-h between the two nodes 102a-n are established, the direction and configuration can be stored and subsequently used without change. Each node 102a-n may provide more than one beam 109a-h to connect to other nodes 102a-n because the wireless environment and traffic load may change over time. Therefore, each node 102a-n monitors signals received from other nodes 102a-n to determine the wireless environment, and dynamically adjusts beam direction and signal configuration to optimize the performance of the system.

One example of the operation of the system is as follows: A first selected node, such as node 102a, generates a beam and steers it toward another selected node, such as node 102b. This can be done by adjusting the complex weights applied to the antenna array elements, which are typically done with beam forming antenna arrays. At the same time, node 102a measures the quality of link A to node 102b. The quality of the link A may be measured with a signal to noise ratio, bit or frame error rate, or some other measurable quality indicator. The transmitting node 102a finds the best antenna beam direction, in this case the best combination of weights to maximize link quality and stores both the link quality measurement and the corresponding beam direction (weighting). The transmitting node 102a does this for all nodes in the vicinity and stores the corresponding quality and beam information.

Any node 102a-n may be flexibly and wirelessly connected or disconnected to other nodes 102a-n by selectively directing one or more beams to the other nodes 102a-n. In FIG. 1, the first node 102a sends a message to the second node 102b using the directional beam A and a message to the fourth node 102d using the directional beam B. In FIG. The directional beams A and B can be controlled independently and transmitted simultaneously. Since each directional beam A and B emits only in a specific direction, it does not cause excessive interference to other nodes 102a-n or the WTRU.

2 is a block diagram of a node 202 in accordance with the present invention. Node 202 includes a smart antenna 204, a controller 206, a memory 208 and an optional wired link 210. The wired link 210 may be a link to the core network 110 or another node. Node 202 executes signal processing algorithms to adapt to multipath with user movement, changes in the radio frequency environment, and cross channel interference. The radio resource management (RRM) function executed by the controller 206 determines how radio resources should be allocated at the node 202.

The smart antenna 204 can include multiple antenna elements (not shown) to generate multiple directional beams under the control of the controller 206. Each beam functions as a wireless connection between node 202 and other nodes. As discussed above, because node 202 is typically fixed at a particular location, the beam direction and configuration between the two nodes may be predetermined and stored in memory 208. The memory 208 maintains a list of other nodes and the beam direction and configuration for each of these other nodes. When node 202 is required to send a message, such as backhaul data, to another node, controller 206 retrieves corresponding beam direction and configuration information from memory 208 and generates a directional beam that is steered in a particular direction. And transmits messages using the beam.

In the case of hybrid node 102n, this process is preceded in establishing a wireless connection to other nodes with the help of smart antenna 204. When the hybrid node 102n establishes a backhaul connection to the core network 110 or another node, there is no configuration information or beam selection since the wired link 210 will be physically fixed and always provide a connection between the same two nodes. .

According to the invention, the smart antenna 204 is preferably equipped with a multi-beam function, each beam can be used independently. Node 202 may generate more than one directional beam to transmit backhaul data to multiple other nodes at the same time. Since the same frequency can be reused for more than one directional beam of the same coverage area, system capacity is substantially increased.

Some nodes may be combined with some beams. This makes it convenient to change the connection and dynamically adapt to changes in the wireless environment. For example, two beams may be provided for a connection between two nodes. If one beam experiences excessive interference, nodes can switch to another beam for message transmission.

The use of smart antennas allows for flexible backhaul link formation between nodes. Each node is configured to generate a plurality of directional beams and can steer the directional beams in any direction in azimuth, so when a new node is added to the network 100, the conventional nodes are directed to the new node. By simply setting the beam direction and configuration, a new connection can be established at the new node. Also, when a conventional node is removed from the network 100, the nodes can simply delete the beam direction and configuration information for the removed node from the memory 208. The present invention eliminates facilities that are not needed to make additional installations or to establish or remove connections between nodes. It goes without saying that the present invention can be implemented in either a mesh network or a cellular network.

One of the strengths of mesh networking is the ability to create new links and drop other links between nodes that depend on a number of factors including traffic load, interference, and individual node performance. As shown in FIG. 1, multiple nodes 102a-n are coupled to each other using smart antennas. Lines between nodes 102a-n in FIG. 1 indicate possible links A-F. Control can be centralized, whereby at least one node can function as a control node to control or distribute connections between nodes, where control is distributed across several nodes or all nodes. If one node is designated as the control node, the control node collects information about the traffic conditions and capabilities of each node and determines the best traffic route for sending messages from one node to another. .

Each node 102a-n preferably transmits one or more beacon signals in its one or more beams, which provide useful information for network operation. For example, beacon signals may transmit current power level, traffic level, interference level, and other parameters. Beacon signals also include connection priority, security, identification, and other changing types of access control and security control information. Beacon signals are measured periodically or aperiodically, and parameters are used as the basis for coordinating connections between nodes to find the most efficient traffic route. Forming at least some of the backhaul connections wirelessly using the smart antenna according to the present invention allows flexibility and reduces unnecessary cost and time in establishing and coordinating connections between nodes.

For example, as shown in FIG. 1, if the traffic load between the second node 102b and the fourth node 102d is very large, the other nodes may be nodes 102b, d as described in detail below. The traffic conditions between the two nodes 102b, d are recognized by reading the beacon signals. If the first node 102a routes the traffic to the fifth node 102e, it will avoid the second and fourth nodes 102b, d if possible and alternatively direct traffic through the Nth node 102n. Will route.

Not only does the present invention have the advantage of providing a flexible, wireless mesh network, the backhaul information (typically transmitted over a wired line) can now be transmitted over the same flexible links via a smart antenna. Implementing this type of common smart antenna scheme in accordance with the present invention provides significant advantages over current wireless communication systems.

3 is a flow diagram of a process 300 for using smart antennas in message transmission between nodes in accordance with the present invention. At least some of the nodes are provided with at least one smart antenna, which is configured to generate multiple directional beams and then to independently steer in azimuth (step 302). Each beam is used as a wireless connection to other nodes in addition to the normal traffic of downloads to and uploads from the WTRU. Each node maintains a list of other nodes and beam direction and configuration information used for transmission to the other nodes. Steps 302 and 304 are typically performed by setting up the system or reconfiguring the system to accept or delete nodes, and typically will not need to be formed during normal operation. When the source node needs to transmit to the target node, the source node retrieves beam direction and configuration information for the target node from memory and generates a directional beam using the beam direction and configuration information (step 306). If the node is selected for transmission of backhaul data, based on other considerations such as link quality and traffic density, the transmitting node selects a beam direction (weighting) from the list and applies it to the antenna.

As the environment may change and beam direction adjustment may be necessary, the process of measuring the quality of the link and storing the relevant information needs to be done periodically. The source node transmits to the target node in the generated directional beam (step 308).

In an optional step, changes in the network may occur, such that new nodes may be added to the network, conventional nodes may be removed from the network, or radio frequencies or other conditions may change. In response to the change, the other nodes update the list of beam direction and configuration information to reflect the change (step 310).

Although the features and elements of the present invention have been described in the preferred embodiments of a particular combination, each feature or element may be used alone or in combination with or other features and elements of the present invention without the other features and elements of the preferred embodiments. It can be used in various combinations without.

Claims (20)

In a wireless communication node,
An antenna array; And
A controller operatively coupled with the antenna array and configured to establish a wireless cellular connection with a plurality of nodes,
The first node of the plurality of nodes is connected to the core network by wire,
At least a second node of the plurality of nodes is not wired to the core network,
The controller is further configured to exchange backhaul data with the first node other than the second node via a wireless cellular connection,
The controller is further configured to receive wireless beamformed backhaul data from the first node and to transmit wireless beamformed data to the second node,
The controller is further configured to change the beam to the second node in response to the measured channel conditions. The method of claim 1,
Wherein the wireless communication node is in a fixed location. The method of claim 1,
Further comprising a memory,
The controller is further configured to store beamforming data and channel quality information for at least the second node. The method of claim 3,
The controller is further configured to transmit wireless beamformed data to a third node,
And the wireless beamformed data is not backhaul data. The method of claim 1,
And the controller is further configured to transmit beamformed backhaul data to the first node. In the method,
A plurality of nodes by a wireless communication node-a first node of the plurality of nodes is wired to a core network, and at least a second node of the plurality of nodes is wired to the core network. Not connected with-establishing a wireless cellular connection with; And
Exchanging backhaul data with the first node other than the second node via a wireless cellular connection by the wireless communication node.
Including;
The backhaul data received from the first node and the data transmitted to the second node are beamformed,
The beam formed by the second node is changed in response to measured channel conditions. The method of claim 6,
And the wireless communication node is in a fixed location. The method of claim 6,
Storing, by the wireless communication node, beamforming data and channel quality information for at least the second node in a memory. The method of claim 8,
The wireless communication node transmits wireless beamformed data to a third node,
And the wireless beamformed data is not backhaul data. The method of claim 6,
Wherein the wireless communication node transmits beamformed backhaul data to the first node. In a fixed position wireless communication node,
An antenna array;
A wireline connection coupled operatively with at least the core network; And
A controller operatively coupled with the antenna array and the wireline connection and configured to exchange backhaul data over the wireline connection
Including,
The controller is further configured to establish a wireless cellular connection with the plurality of nodes,
The controller is further configured to exchange backhaul data via a wireless cellular connection of a first node with a first node of the plurality of nodes,
The controller is further configured to transmit wireless beamformed backhaul data to the first node using the antenna array,
The controller is further configured to exchange data that does not include backhaul data through a wireless cellular connection of a second node with a second node of the plurality of nodes,
The controller is further configured to transmit wireless beamformed data to the second node using the antenna array,
And the controller is further configured to adjust beams to the first node and the second node in response to measured channel conditions. The method of claim 11,
Further comprising a memory,
The controller is further configured to store beamforming data and channel quality information for at least the first node and the second node. The method of claim 11,
The controller is further configured to transmit wireless beamformed data to a third node,
And the wireless beamformed data is not backhaul data. The method of claim 11,
And the controller is further configured to receive wireless beamformed backhaul data from the first node. The method of claim 11,
The controller is further configured to transmit non-backhaul data to the first node,
And the non-backhaul data is for a third node connected to the first node and not to the wireless communication node at the fixed location. In the method,
Exchanging backhaul data via a wireline connection, the wireline connection coupled to at least the core network, by a wireless communication node in a fixed location;
Establishing, by the fixed location wireless communication node, a wireless cellular connection with a plurality of nodes;
The backhaul data transmitted to the first node through the wireless cellular connection of a first node and a first node of the plurality of nodes by the wireless communication node of the fixed location is beamformed. Exchanging;
The wireless communication node at the fixed location does not include backhaul data through a wireless cellular connection between a second node and a second node of the plurality of nodes-data transmitted to the second node is beamformed ( beamformed); And
Adjusting beams to the first node and the second node in response to measured channel conditions by the fixed position wireless communication node.
≪ / RTI > The method of claim 16,
And the wireless communication node at the fixed location stores beamforming data and channel quality information for at least the first node and the second node. The method of claim 16,
Transmitting, by the wireless communication node at the fixed location, wireless beamformed data to a third node
More,
And the wireless beamformed data is not backhaul data. The method of claim 16,
Receiving, by the wireless communication node at the fixed location, wireless beamformed backhaul data from the first node
≪ / RTI > The method of claim 16,
The wireless communication node in the fixed position transmits non-backhaul data to the first node,
And the non-backhaul data is for a third node connected to the first node and not to the wireless communication node at the fixed location.

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