FIELD OF THE INVENTION

The present invention relates to wireless communication and more particularly to backhauling the traffic wirelessly.

DESCRIPTION OF THE BACKGROUND ART

In wireless communication, providing backhaul means to get data from an end user to a node in a major network such as the Internet, network of any academic institution or government agency etc.

Fig. 1 shows typical backhaul network architecture 100. The architecture comprises one or more optical hubs wirelessly connected to a plurality of leafnodes.

Manufacturers of network switching equipment use the term backhaul to refer to the process of getting data to the network backbone. Backhaul is also used to get non-live audio and video material to distribution points at major broadcast news organizations.

A typical mechanism to backhaul 2G/3G traffic is to use microwave in 15GHz and 23GHz band. Backhaul in the metro area involves using the microwave to backhaul the traffic from 2G and 3G Base station. The usage of

TDM (Time Division Multiplexing) to Ethernet converter in 2G and the Ethernet option for backhaul in 3G requires migration of existing TDM based microwave to hybrid/packet based microwave.

However, the microwave based backhaul is inefficient as it uses symmetric link for both Downlink (DL) and Uplink (UL). The microwave backhaul are usually connected in a hub and hence do not provide mechanism for redundancy in case of hub failure Publication number: US 2011/0044279 A1 describes a method implemented in an anchor base station configured performing a proxy operation at an anchor base station in which the anchor base station acts as a proxy between a second S-GW or an MME node and a self-backhauled base station. The method includes receiving a data packet destined for the user equipment and mapping the received data packet from an incoming General Packet Radio Service (GPRS) Tunneling Protocol (GTP) tunnel to an outgoing GTP tunnel. The method also includes receiving a control message and modifying elements of the control message while copying other elements in the control message and forwarding the control message between the self-backhauled base station and the second S-GW or MME node.

The above-mentioned patent publication does not teach how to provide redundancy option in case of changes in the traffic.

Publication number: US 2009/0323621 A1 mentions a method and system for providing wireless backhaul in a wireless radio access network having an overall allocated access bandwidth for access communication, the system including a radio access base station designed for out-of-band backhaul, the base station including an access transceiver communicating over an allocated frequency channel within the overall allocated access bandwidth, and an in-band backhaul unit coupled to the access base station including means for in-band communication of backhaul of the access base station.

The above-mentioned patent publication does not provide backhauling for whole spectrum.

Therefore there is required a novel scheme of backhauling for wireless communication.

SUMMARY

An object of this invention is to provide multi-sector user LTE (Long Term Evolution) scheme with directed antennas to provide backhaul.

In accordance with this there is provided a method and a system for backhauling traffic wirelessly in an Ethernet communication network.

In one embodiment of the present invention atleast two hub nodes are configured wherein one act as a master hub node and another as a slave hub node. Each hub node may be connected to one or more leaf nodes using dual homed directed antennas from the leaf node to two hub nodes. The directed antenna in the hub node and leaf node may be aligned in a manner such that antenna lobes of both the antenna are directed to each other and provide the highest signal to noise ratio along the radio link using 256 QAM in both uplink and downlink.

In one embodiment herein, all the traffic may be sent from the leaf nodes to the hub nodes. If multiple leaf node are present, few nodes consider any one hub node as master and the remaining nodes consider the another hub node as master thereby improving efficiency by load balancing.

In case a leaf node happens to know of the failure of master hub node on non-reception of signal, it would initiate the connection to the slave hub node.

In one embodiment herein, the hub nodes exchange periodic information with each other at regular intervals. Also a keep-alive message may be provided and all higher overhead information may be stopped from being sent to keep the interface overhead to minimum.

Other objects, features and advantages of the invention will be apparent from the drawings, and from the detailed description that follows below.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will be made to embodiments of the invention, examples of which may be illustrated in the accompanying figures.

Fig. 1 shows typical backhaul network architecture.

Fig. 2 shows expanded view of a leaf node as per an embodiment of the present invention.

Fig. 3 is a flowchart illustrating the backhauling as per an embodiment of the present invention.

DESCRIPTION OF THE INVENTION

The present invention described herein, discloses a method and a system for backhauling in a wireless communication network. In one embodiment herein, atleast two hub nodes are configured such that any one of these act as a master hub node and another as a slave hub node. Each hub node may be connected to one or more leaf nodes using dual homed directed antennas from the leaf node to two hub nodes. The directed antenna in the hub node and leaf node may be aligned in a manner such that antenna lobes of both the antenna are directed to each other and provide the highest signal to noise ratio along the radio link using 256 QAM in both uplink and downlink.

In the following description, for purpose of explanation, specific details are set forth in order to provide an understanding of the invention. It will be apparent, however, to one skilled in the art that the invention may be practiced without these details. One skilled in the art will recognize that embodiments of the present invention, some of which are described below, may be incorporated into a number of different systems. The best mode of the invention described in the specification illustrates the exemplary embodiment of the invention. It is understood that one skilled in art may modify or change the modules used in the best mode of invention.

Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment.

FIG. 2 shows expanded view of a leaf node as per an embodiment of the present invention. The leaf node 201 comprises two directed antennas 202a and 202b, a BBU (Base band unit) 204, an RRH (Radio Remote head) 203. The BBU 204 is connected to RRH 203 over optical or electrical line. The connection between RRH 203 and antenna 202a, 202b will be RF wave guides. With "n" directional antenna each optical hub node can handle up to n leaf nodes. The BBU 204 supports 2x2 MIMO (Multiple Input Multiple Output) and the two directed antennas 202a and 202b.

The directed antenna 202a and 202b in the optical hub node and speacialized UE (User Equipment) leaf node 201 will be aligned so that the antenna lobe of both the antenna 202a and 202b are directed to each other and provide the highest signal to noise ratio along the radio link using the 256 QAM in both uplink and downlink. With "n" number of directional antennas each optical hub node may have capability of handling up to 'n' number of leaf nodes.

As per the embodiments of the present invention the hub nodes exchange periodic information with each other at regular intervals. Also, a keep-alive message is provided and all higher overhead information is stopped from being sent to keep the interface overhead to minimum.

As explained above, atleast two hub nodes are configured wherein one act as a master hub node and another as a slave hub node. Each hub node may be connected to one or more leaf nodes using dual homed directed antennas from the leaf node to two hub nodes. A leaf node will know of the failure of master hub node on non-reception of signal and would initiate the connection to the slave hub node.

Further, the master and slave hub node synchronize the bearer layer (virtual connection with a specified QoS) so that as soon as the leaf node connects to the slave hub the session need not be re-established and set-up time is minimal. Furthermore, an independent leaf-node stack is allowed to run for the ports which are connected to each hub node.

According to various embodiments herein, the optical hub node may be an LTE (Long Term Evolution) base station consisting of a BBU (Base band unit), an RRH (Radio Remote head) handling "n" sector 2x2 MIMO and 2n directed antenna's antenna's along with a WAN connectivity on Fiber. The BBU may be connected to RRH over optical or electrical line. Further, the connection between RRH and antenna may be done through RF wave guides.The hub nodes may be connected to each other either via a wireless medium or via fiber/copper wire whereas the leaf nodes may be connected with hub nodes through a wireless medium.

For TDD based LTE, the Downlink to Uplink Ratio is configurable depending on the backhaul capacity required for the uplink and downlink.

The power level of antenna will be set depending on the distance of the leaf and hub node.

Fig. 3 is a flowchart illustrating the backhauling as per an embodiment of the present invention. In the process of backhauling the traffic wirelessly, initially at least two hub nodes one as a master hub node and another as a slave hub node are configured. Thereafter the base stations or the hub nodes are checked in step 301 for Ethernet. If a base station or the optical hub node has the

Ethernet card, then Base station is connected in step 302 to the leaf node over FE/GE port. If a base station or the optical hub node does not have the Ethernet card, then circuit emulation is used for Ethernet conversion before connecting in step 303 it to the leaf node over FE/GE port.

Thereafter the hub nodes are checked in step 304 for redundancy. If redundancy is not needed, then the leafnode is connected in step 305 over a single LTE directional link to either master hub node or the slave hub node. If redundancy is needed, then the leaf node is connected in step 306 over LTE directional links in a dual homing fashion. In other words each hub node is connected to one or more leaf nodes using dual homed directed antennas from the leaf node to the hub node, the directed antenna in the hub node and leaf node being aligned in a manner such that antenna lobes of both the antenna are directed to each other and provide the highest signal to noise ratio along the radio link.

Thereafter the capacity of backhaul with QPSK, 16 QAM or 64 QAM MCS is checked in step 307. If enough capacity is found, then the appropriate MCS is used in step 308 as required to support the backhaul capacity. Otherwise 256 QAM is used in step 309 in the directional LTE link.

Thereafter backhaul is sent only on one LTE directional link and in case the link is down a connection is initiated to the other optical hub and backhaul to the other link is established in step 310.

The foregoing description of the invention has been described for purposes of clarity and understanding. It is not intended to limit the invention to the precise form disclosed. Various modifications may be possible within the scope and equivalence of the appended claims.

We claim:

1. A method for backhauling traffic wirelessly, the method comprising the steps of:

configuring at least two hub nodes one as a master hub node and another as a slave hub node;

connecting each hub node to one or more leaf nodes using dual homed directed antennas from the leaf node to two hub nodes, the directed antenna in the hub node and leaf node being aligned in a manner such that antenna lobes of both the antenna are directed to each other and provide the highest signal to noise ratio along the radio link using 256 QAM in both uplink and downlink; and

sending all the traffic from the leaf nodes to the hub nodes ;

wherein if multiple leaf nodes are present, few nodes consider any one hub node as master and the remaining nodes consider the another hub node as master thereby improving efficiency by load balancing.

2. The method as in claim 1 wherein the hub nodes exchange periodic information with each other at regular intervals.

3. The method as in claim 1 wherein a keep-alive message is provided and all higher overhead information is stopped from being sent to keep the interface overhead to minimum.

4. The method as in claim 1 wherein a leaf node will know of the failure of master hub node on non-reception of signal and would initiate the connection to the slave hub node.

5. The method as in claim 1 wherein the master and slave hub node synchronize the bearer layer (virtual connection with a specified QoS) so that as soon as the leaf node connects to the slave hub the session need not be reestablished and set-up time is minimal.

6. The method as in claim 1 wherein an independent leaf-node stack is allowed to run for the ports which are connected to each hub node.

7. The method as in claim 1 wherein the optical hub node is an LTE (Long Term Evolution) base station consisting of a BBU (Base band unit), an RRH (Radio Remote head) handling "n" sector 2x2 MIMO and 2n directed antenna's antenna's along with a WAN connectivity on Fiber.

8. The method as in claim 7 wherein the BBU is connected to RRH over optical or electrical line.

9. The method as in claim 7 wherein the connection between RRH and antenna is RF wave guides.

10. The method as in claim 1 wherein the hub nodes are connected to each other either via a wireless medium or via fiber/copper wire, and wherein the leaf nodes are connected with hub nodes through a wireless medium.

11. The method as in claim 1 wherein with "n" directional antenna each optical hub node is capable of handling up to 'n' number of leaf nodes.

12. The method as in claim 1 wherein the leaf node consists of a specialized UE (User Equipment) BBU supporting 2x2 MIMO and two directed antenna.

13. The method as in claim 1 wherein the power level of directed antenna is set depending on the distance of the leaf and hub node.

14. The method as in claim 1 wherein for TDD based LTE, the Downlink to Uplink Ratio is configurable depending on the backhaul capacity required for the uplink and downlink.

15. A system for backhaul, the system comprising:
at least two hub nodes, one configured as a master hub node and another as a slave hub node;

one or more leaf nodes, each connected to two hub nodes and all the traffic being sent from the leaf node to the hub nodes; and

dual homed antennas for connecting each hub node to one or more leaf nodes, the directed antenna in the hub node and leaf node being aligned in a

manner such that antenna lobes of both the antenna are directed to each other and provide the highest signal to noise ratio along the radio link using 256 QAM in both uplink and downlink,

wherein if multiple leaf node are present, few nodes consider any one hub node as master and the remaining nodes consider the another hub node as master thereby improving efficiency by load balancing.