Embodiments presented herein relate to a base station and a method in a base station. In particular, embodiments relate to traffic management for integrated access and backhaul traffic.
In the self-backhauled network of
The anchor base station is connected to the core network, e.g. by a fiber-optic link.
Integrated access and backhaul is specified within 3GPP for LTE relaying. Relaying can in this case be regarded as an access-integrated backhaul technology. In LTE, an in-band relayed eNB, i.e. a self-backhauled RBS, receives its wireless backhaul connection from a donor eNB. The donor eNB thus allocates parts of its radio resources to provide the relayed eNB with backhaul connectivity. The more backhaul capacity the relayed eNB needs, the more radio resources the donor eNB must allocate to backhaul traffic. In such a setup, the radio resources are shared between access and backhaul links which implies that access and backhaul links compete over the same radio resource pool.
The self-backhauled network can also be a multi-hop link.
As mentioned above, a problem when deploying access-integrated backhaul networks is that access and backhaul links compete over the same radio resource pool. Hence, an increase in access traffic can lead to shortage of radio resources for backhaul links, especially in a multi-hop deployment where each radio base station of the backhaul chain adds further access traffic on top the incoming backhaul traffic. This can lead to poor backhaul connection, which in turn affects user experience and results in poor usage of radio resources.
The self-backhauled networks described above will easily be overloaded and not able to provide the backhaul capacity required for a consistent user experience. Currently there exist no efficient implementations that remedy this problem. Hence, there is a need for an improved radio base station for integrated access and backhaul traffic that can reduce the problems of network overload and congestion in a self-backhauled network.
It is an object of the present invention to remedy, or at least alleviate, some of these drawbacks and to provide an efficient radio base station and method for traffic management in a self-backhauled network. This is provided in a number of aspects of the present invention described below.
According to a first aspect, the invention describes a radio base station for integrated access and backhaul. The radio base station being configured to allocate a first part of its capacity to access traffic and a second part of its capacity to backhaul traffic. The radio base station being further configured to form a self-backhauled network with a plurality of other radio base stations, thus allowing each radio base station to be connected to the core network via the self-backhauled network. The radio base station is comprising a receiver configured to receive incoming capacity grants from adjacent radio base stations in the self-backhauled network, wherein the incoming capacity grants are indicating the capacity granted for backhaul traffic via the respective adjacent radio base station. The radio base station is also comprising a routing unit configured to select a backhaul route based on the incoming capacity grants. The radio base station is also comprising a transmitter configured to transmit the backhaul traffic to an adjacent radio base station in accordance with the selected backhaul route.
According to a second aspect, the invention describes a method in a radio base station, in which the radio base station is configured to allocate a first part of its capacity to access traffic and a second part of its capacity to backhaul traffic. The radio base station is further configured to form a self-backhauled network with a plurality of other radio base stations, thus allowing each radio base station to be connected to the core network via the self-backhauled network. The method is comprising the step of receiving incoming backhaul capacity grants from adjacent radio base stations in the self-backhauled network. The incoming capacity grants indicating the capacity granted for backhaul traffic via the respective adjacent radio base stations. The method is also comprising the step of selecting a backhaul route for the outgoing backhaul traffic of the radio base station based on the incoming backhaul grants. Lastly, the method is comprising the step of transmitting the outgoing backhaul traffic in accordance with the selected backhaul route.
The above radio base station and method can largely avoid network overload and congestion and provide efficient and dynamic traffic management for a self-backhauled network.
The drawings are not necessarily to scale and the dimensions of certain features may have been exaggerated for the sake of clarity, emphasis is instead being placed upon illustrating the principle of the embodiments herein.
This invention relates to signalling procedure for establishing a backhaul connection between a radio base stations, RBS, and its adjacent radio base stations in a self-backhauled network. The invention also relates to traffic management of said established connection. The invention may be used for both uplink and downlink backhaul traffic, and the invention is applicable to both fixed wireless access and mobile wireless access.
Four embodiments of the present invention are described in detail below with reference to
RBS 210 and RBS 250. RBS 230 and 240 will in this deployment always have two possible backhaul routes. Backhaul traffic to and from RBS 220 will always have to be directed via RBS 230. Hence, RBS 220 should not be used as donor for uplink backhaul traffic.
The first and second embodiments relate to a radio base station 230 for integrated access and backhaul. The radio base station 230 is configured to allocate a first part of its capacity to access traffic and a second part of its capacity to backhaul traffic. The radio base station is further configured to form a self-backhauled network 260, 360, 460 with a plurality of other radio base stations 210, 220, 240, 250. The self-backhauled network may be arranged as a line, a ring, a mesh, a star, a tree or any combination thereof. At least one of the radio base stations of the self-backhauled network needs to be an anchor radio base station 210, 250. The anchor RBS 210, 250 is characterized by having a dedicated backhaul connection, e.g. microwave radio, copper or a fiber-optic link, that is connected to the core network 280. Each radio base station in the self-backhauled network will thus be able to connect to the core network 280 via the self-backhauled network.
In the following, features of the first embodiment are described with reference to
The receiver 231 is configured to receive incoming capacity grants 710B, 720A from adjacent radio base station. Each incoming capacity grant will indicate the granted data rate for backhaul traffic from the radio base station 230 to a target radio base station 210, 220, 240, 250 in the self-backhauled network. The invention works for both uplink and downlink backhaul traffic. For uplink backhaul traffic, the target base station is an anchor radio base station, i.e. RBS 210 or RBS 250. For downlink backhaul traffic, the target base station is a radio base station without a dedicated backhaul link 270A, 270B to the core network 280, i.e. RBS 220 or RBS 240.
The routing unit 222, 232 is configured to select a backhaul route 730A, 730B based on the incoming capacity grants 710B, 720A. Selecting backhaul route may here imply just selecting an adjacent radio base station, or alternatively, it may imply selecting a full route to the target base station. In one example, the routing unit may be configured to select the backhaul route via the adjacent radio base station that provides the highest granted data rate. If several backhaul routes indicate a granted data rate that is greater than or equal to the capacity requirements of RBS 230, the routing unit may be configured to select the backhaul route with the fewest number of hops to the target base station. In another example, the routing unit may be configured to select the backhaul route associated with the first incoming capacity grant having a granted data rate that is greater than or equal to the capacity requirements of RBS 230. In yet another example, the routing unit may be configured to select the backhaul route via the adjacent radio base station that provides the lowest granted data rate that is still greater than the backhaul capacity requirement of RBS 230. In yet another example, the routing unit may be configured to select a first backhaul route 730A, 740A for a first portion of the backhaul traffic, and select a second backhaul route 730B for a second portion of the backhaul traffic.
After the backhaul route has been selected, the transmitter 233 is configured to transmit the backhaul traffic to an adjacent radio base station in accordance with the selected backhaul route.
In the example of
The example of
In the following, features of the second embodiment are described with reference to
As mentioned, the incoming capacity grants of an RBS in the self-backhauled network comprises a granted data rate to a target base station. The incoming capacity grants may also comprise other network information, e.g. network topology, number of connected UEs and information about traffic prioritizing. For example, public safety or emergency traffic should be prioritized over other backhaul traffic. Also, time critical traffic, such as voice may have higher prioritizing than other backhaul traffic, e.g. file download.
The processing unit 224, 234 is configured to determine an outgoing capacity grant 820B. The outgoing capacity grant indicate the granted data rate for backhaul traffic from the radio base station 230 to a target radio base station 210, 220, 240, 250 in the self-backhauled network. The second embodiment works for both uplink and downlink backhaul traffic. For uplink backhaul traffic, the target base station is an anchor radio base station, i.e. RBS 210 or RBS 250. For downlink backhaul traffic, the target base station is a radio base station without a dedicated backhaul link 270A, 270B to the core network 280, i.e. RBS 220 or RBS 240.
The granted data rate may be determined based on one or more of the below items:
The granted data rate may further be determined based on the position of the radio base station 230 in the self-backhauled network. For example, a leaf node in the self-backhauled network, e.g. RBS 220 of deployment 400, should never grant capacity to uplink backhaul traffic of any other radio base station.
Lastly, the transmitter 233 is configured to transmit the outgoing capacity grant 820B to an adjacent radio base station.
In the example of
The third and fourth embodiments relate to a method in a radio base station 230. The radio base station is configured to allocate a first part of its capacity to access traffic and a second part of its capacity to backhaul traffic. The radio base station is further configured to form a self-backhauled network 260, 360, 460 with a plurality of other radio base stations 210, 220, 240, 250. The self-backhauled network may be arranged as a line, a ring, a mesh, a star, a tree or any combination thereof. At least one of the radio base stations of the self-backhauled network needs to be an anchor radio base station 210, 250. The anchor RBS 210, 250 is characterized by having a dedicated backhaul connection, e.g. microwave radio, copper or a fiber-optic link, that is connected to the core network 280. Thus, allowing each radio base station to be connected to the core network 280 via the other radio base stations in the self-backhauled network.
In the following, features of the third embodiment are described with reference to
The method is comprising the step of receiving 610 incoming capacity grants 710B, 720A from adjacent radio base stations in the self-backhauled network. Each incoming capacity grant indicates the granted data rate for backhaul traffic from the radio base station 230 to a target radio base station in the self-backhauled network. For uplink backhaul traffic, the target base station is an anchor radio base station, i.e. RBS 210 or RBS 250. For downlink backhaul traffic, target base station is a radio base station without a backhaul link 270A, 270B, i.e. RBS 220 or RBS 240.
The method is further comprising the step of selecting 620 a backhaul route for the backhaul traffic of the radio base station 230 based on the incoming backhaul grants 710B, 720A. The step of selecting may involve just selecting an adjacent radio base stations, or alternatively, it may involve selecting the full route to the target base station. In one example, the step of selecting 620 a backhaul route may comprise selecting a backhaul route via the adjacent radio base station that provides the highest granted data rate. If several backhaul routes indicate a granted data rate that is greater than or equal to the capacity requirements of RBS 230, the step of selecting may comprise selecting the backhaul route with the fewest number of hops to the target base station. Thus, reducing latency. Alternatively, if several backhaul routes indicate a granted data rate that is greater than or equal to the capacity requirements of RBS 230, the step of selecting may comprise selecting a backhaul route randomly. In yet another example, the step of selecting 620 a backhaul route may comprise selecting a backhaul route via the adjacent radio base station that provides the lowest granted data rate that is still greater than the backhaul capacity requirement of RBS 230. In yet another example, the routing unit may be configured to select a first backhaul route 730A, 740A for a first portion of the backhaul traffic, and select a second backhaul route 730B for a second portion of the backhaul traffic.
Lastly, the method is further comprising the step of transmitting 630 the backhaul traffic in accordance with the selected backhaul route.
In the following, features of the fourth embodiment are described with reference to
As mentioned earlier, the incoming capacity grants comprises a granted data rate. The incoming capacity grants may also comprise other network information, e.g. network topology, number of connected UEs and information on traffic prioritizing. For example, public safety or emergency traffic should be prioritized over other backhaul traffic. Also, time critical traffic, such as voice may have higher prioritizing than other backhaul traffic, e.g. file download.
The method is further comprising the step of determining 640 an outgoing capacity grant 820B for an adjacent radio base station in the self-backhauled network. The outgoing capacity grant indicates the granted data rate for backhaul traffic to a target radio base station in the self-backhauled network via the radio base station 230. For uplink backhaul traffic, the target base station is an anchor radio base station, i.e. RBS 210 or RBS 250. For downlink backhaul traffic, target base station is a radio base station without a backhaul link 270A, 270B, i.e. RBS 220 or RBS 240.
The step of determining may comprise determining the granted data rate based on one or more of the below items:
The step of determining may further comprise determining the granted data rate based on the position of the radio base station 230 in the self-backhauled network 260. For example, a leaf node in the self-backhauled network, e.g. RBS 220 of deployment 400, should never grant capacity to uplink backhaul traffic of any other radio base station.
Lastly, the method is further comprising the step of transmitting 660 the outgoing capacity grant to the adjacent radio base stations in the self-backhauled network.
In the following, some alternative aspects of the four embodiments are described.
According to an aspect of the invention, a fixed minimum radio resource is allocated in a semi persistent manner for the backhaul links between the radio base stations.
According to another aspect of the invention, an RBS receives a plurality of capacity grants from adjacent radio base stations. A third RBS receives a capacity grant from a first RBS. The third RBS also receives a capacity grant from a second RBS. The third RBS removes its own need for backhaul and access and adds the capacity grant from the first RBS and the second RBS. The third RBS then distributes an outgoing capacity grant to a fourth RBS that have a backhaul connection to the third RBS.
According to yet another aspect of the invention, an RBS sends a plurality of capacity grants to adjacent radio base stations. A second RBS receives a capacity grant from at least a first RBS. The second RBS removes its own need for backhaul and access. The second RBS then divides its available resources between a third RBS and a fourth RBS. The first RBS sends a first capacity grant to a third RBS and a second capacity grant to a fourth RBS.
According to yet another aspect of the invention, an RBS may update the outgoing capacity grant based on change in its resource utilization.
According to yet another aspect of the invention, the capacity grant received from other radio base stations may be reduced with the amount of traffic corresponding to devices or UEs for which RBS has a direct access connection.
According to yet another aspect of the invention, each capacity grant may be associated with a prioritization indication.
According to yet another aspect of the invention, an RBS sends a backhaul capacity request to at least one adjacent RBS. This request might be triggered by a high radio resource utilization close to a threshold value. The requested RBS then sends a capacity grant to the requesting RBS based on its own access data and its own capacity grants from other radio base stations. Each RBS, may have a table in which all candidate radio base stations that can potentially provide backhaul connection to it are listed.
According to yet another aspect of the invention, the radio base station 230 may be implemented as a processing unit 901, a memory 902, input/output unit 903 and a clock 904 as is illustrated in
It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components, but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. It should also be noted that the words “a” or “an” preceding an element do not exclude the presence of a plurality of such elements.
Filing Document | Filing Date | Country | Kind |
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PCT/EP2017/073836 | 9/20/2017 | WO | 00 |