WO2019108101A1

WO2019108101A1 - A fixed wireless communication system with scheduling

Info

Publication number: WO2019108101A1
Application number: PCT/SE2017/051193
Authority: WO
Inventors: Mona HASHEMI; Mikael Coldrey; Sven Petersson; Martin Johansson
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2017-11-30
Filing date: 2017-11-30
Publication date: 2019-06-06

Abstract

The present disclosure relates to a fixed wireless communication system (1) comprising a system controller module (2), at least two first type nodes (AN1, AN2, AN3, AN4), and at least two second type nodes (CPE1, CPE2, CPE3, CPE4, CPE5, CPE6, CPE7, CPE8, CPE9, CPE10, CPE11, CPE12). Each first type node (AN1, AN2, AN3, AN4) is adapted to communicate with at least one corresponding second type node (CPE1, CPE2, CPE3, CPE4, CPE5, CPE6, CPE7, CPE8, CPE9, CPE10, CPE11, CPE12) by means of at least one corresponding antenna beam (10a, 10b, 10c; 11a, 11b, 11c). The system controller module (2) is adapted to schedule transmission and reception time slots for the beams (10a, 10b, 10c; 11a, 11b, 11c), and/or to schedule different frequency slots for the beams (10a, 10b, 10c; 11a, 11b, 11c), such that interference between nodes (CPE1, CPE2; AN1, AN4), which nodes (CPE1, CPE2; AN1, AN4) are disposed to interfere with each other to a certain degree if one node is transmitting and the other node is receiving at the same frequency, is reduced.

Description

A fixed wireless communication system with scheduling

TECHNICAL FIELD

The present disclosure relates to a fixed wireless communication system comprising a system controller module, at least two first type nodes and at least two second type nodes. Each first type node is adapted to communicate with at least one corresponding second type by means of at least one corresponding antenna beam. BACKGROUND

Access-integrated backhaul is not new, and for example in LTE (Long-Term Evolution) the term relaying is specified, which in principle relates to a relayed (self- backhauled) eNB (e-node B, i.e. a base station) that receives its wireless backhaul connection from a donor eNB. The donor eNB will have to allocate 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 the backhaul of the relayed eNB.

In such a setup, there is thus a sharing of radio resources between access and backhaul links which implies that access and backhaul links compete over the same radio resources pool. Relaying can be regarded as an access-integrated backhaul technology.

The access-integrated backhaul link can either be a single-hop or multi-hop link. In a multi-hop deployment, the access-integrated backhaul link from one access node is relayed along a certain route from access node to access node until it reaches its destination.

A problem when deploying a multi-hop access-integrated backhaul network e.g. for fixed wireless access (FWA) using fixed beamforming is that users and access nodes with low isolation between them may cause severe interference to each other. Fixed beamforming implies that the spatial coverage area is covered by a fixed number of beams that are static during a certain time, such as during a certain operation. Potentially high interference may occur, which can lead to poor user experience and poor usage of radio resources. It is therefore a desire to provide a fixed wireless communication system where possible interference between users and access nodes is reduced.

SUMMARY

It is an object of the present disclosure to provide a fixed wireless communication system where possible interference between users and access nodes is reduced.

Said object is obtained by means of a fixed wireless communication system comprising a system controller module, at least two first type nodes, each having a corresponding first type antenna arrangement, and at least two second type nodes, each having a second type antenna arrangement. Each first type node is adapted to communicate with at least one corresponding second type node by means of at least one corresponding antenna beam, wherein the system controller module is adapted to schedule transmission and reception time slots for the beams, and/or to schedule different frequency slots for the beams. By means of the scheduling, interference between nodes that are disposed to interfere with each other to a certain degree if one node is transmitting and the other node is receiving at the same frequency, is reduced.

Said object is also obtained by means of a method for reducing interference in a fixed wireless communication system where the method comprises using at least two first type nodes for communicating with at least one corresponding second type node using at least one corresponding antenna beam, and scheduling transmission and reception time slots for the beams, and/or different frequency slots for the beams. By means of the scheduling, interference between nodes that are disposed to interfere with each other to a certain degree if one node is transmitting and the other node is receiving at the same frequency, is reduced. This provides an advantage of having a fixed wireless communication system comprising an access-integrated network with a centralized system controller module that confers an optimized allocation of beams. This makes the network more reliable and robust against interference, and provides enhanced performance compared to prior such systems.

Furthermore, by means of interference mitigation, end-user experience e.g. user data rate will be improved, the users will also experience less outages (dropped connections) and better utilization of radio resources.

According to some aspects, the angular directions of the beams are fixed.

This provides an advantage of having a less complicated fixed wireless communication system.

According to some aspects, when one first type node is arranged to communicate with one second type node, and another first type node is arranged to communicate with another second type node, the system controller module is adapted to schedule transmission and reception time slots such that when said one second type node is transmitting or receiving, said another second type node is inactive. Also, when said another second type node is transmitting or receiving, said one second type node is inactive.

This provides an advantage of enabling the present disclosure to be applied to a fixed wireless communication system adapted for TDD (Time Division Multiplexing).

According to some aspects, when one first type node is arranged to communicate with one second type node, and another first type node is arranged to communicate with another second type node, the system controller module is adapted to schedule frequency slots such that when said one second type node is transmitting or receiving at one corresponding frequency, said another second type node is transmitting or receiving at another corresponding frequency. This provides an advantage of enabling the present disclosure to be applied to a fixed wireless communication system adapted for FDD (Frequency Division Multiplexing). According to some aspects, there is a plurality of second type nodes that are adapted to communicate with one first type node and a second plurality of second type nodes that are adapted to communicate with another first type node. Each first type node is adapted to communicate by means of a corresponding set of antenna beams, where each plurality of second type nodes comprises a number of second type nodes that exceeds the number of antenna beams in the corresponding set of antenna beams.

According to some aspects, there is a plurality of first type nodes, where the first type nodes are adapted to communicate with each other by means of backhaul communication via backhaul antenna beams. When one first type node is arranged to communicate with another first type node, and where a further first type node is disposed to experience interference from said backhaul communication if said one first type node is transmitting and said further node is receiving, the system controller module is adapted to schedule transmission and reception time slots such that when said one first type node is transmitting via a backhaul antenna beam, said further first type node is inactive regarding backhaul communication, and when said further first type node is receiving via a backhaul antenna beam, said one first type node is inactive regarding backhaul communication.

This provides an advantage of having a fixed TDD wireless communication system comprising an access-integrated backhaul network with a centralized system controller module that confers an optimized allocation of backhaul beams as well.

According to some aspects, there is a plurality of first type nodes, where the first type nodes are adapted to communicate with each other via backhaul communication. When one first type node is arranged to communicate with another first type node, and where a further first type node is disposed to experience interference from said backhaul communication if said one first type node is transmitting and said further node is receiving, the system controller module is adapted to schedule frequency slots such that when said one first type node is transmitting or receiving at one corresponding frequency, said further first type node is transmitting or receiving at another corresponding frequency. This provides an advantage of having a fixed FDD wireless communication system comprising an access-integrated backhaul network with a centralized system controller module that confers an optimized allocation of backhaul beams as well.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will now be described more in detail with reference to the appended drawings, where:

Figure 1 shows a schematical view of a first example of a fixed wireless communication system;

Figure 2 shows a schematical view of a second example of a fixed wireless communication system in a first mode of operation;

Figure 3 shows a schematical view of a second example of a fixed wireless communication system in a second mode of operation;

Figure 4 shows a schematical view of a third example of a fixed wireless communication system; Figure 5 shows a schematical view of a fourth example of a fixed wireless communication system;

Figure 6 shows a flowchart of a method according to the present disclosure; and Figure 7 shows a fixed wireless communication system according to some aspects of the present disclosure. DETAILED DESCRIPTION

With reference to Figure 1 , there is a first example of a fixed wireless communication system 1 comprising a system controller module 2, and two first type nodes AN1 , AN2, each having a corresponding first type antenna arrangement 3a, 3b. The first type nodes are of the type access nodes (AN:s) which function as base stations. The fixed wireless communication system 1 comprises six second type nodes CPE1 , CPE2, CPE3, CPE4, CPE5, CPE6, where each first type node is constituted by a so called customer premise equipment (CPE), which here corresponds to a fixed customer node. Each customer node CPE1 , CPE2, CPE3, CPE4, CPE5, CPE6, has a corresponding customer antenna arrangement 6a, 6b, 6c, 6d, 6e, 6f that have corresponding customer node beams 7a, 7b, 7c, 7d, 7e, 7f.

The access nodes AN1 and AN2 have integrated backhaul functionality and single beam transmission/reception. They provide fixed wireless access to the customer premises equipment CPE1 , CPE2, CPE3, CPE4, CPE5, CPE6 at houses. AN1 serves CPE 1 , 3 and 5 by beam switching and provides backhaul connection to AN2 also by beam switching. AN2 serves CPE 2, 4 and 6 by beam switching and provides backhaul connection to AN1 also by beam switching. The beam serving is time- multiplexed between the different connections, i.e. TDM based sharing.

A first access node AN1 is adapted to communicate with a first customer node CPE1 , a third customer node CPE3 and a fifth customer node CPE5 via corresponding antenna beams 10a, 10b, 10c using beam switching, and provides backhaul connection to a second access node AN2 via a first backhaul antenna beam 10d, also by beam switching. The customer nodes CPE1 , CPE3, CPE5 use corresponding customer node beams 7a, 7c, 7e for communication with the first access node AN1.

The second access node AN2 is adapted to communicate with a second customer node CPE2, a fourth customer node CPE4 and a sixth customer node CPE6 via corresponding antenna beams 11 a, 11 b, 11 c using beam switching, and provides backhaul connection to the first access node AN1 via a first backhaul antenna beam 11 d, also by beam switching. The customer nodes CPE2, CPE4, CPE6 use corresponding customer node beams 7b, 7d, 7f for communication with the second access node AN2. The beam serving is time-multiplexed between the different connections, i.e. TDM (Time Division Multiplexing) based sharing.

In this example, the first customer node CPE1 and the second customer node CPE2 are positioned relatively close to each other.

The first customer node CPE1 is served by the first access node AN1 and the second customer node CPE2 is served by the second access node AN2. Hence the first customer node CPE1 is in reception mode, i.e. DL (downlink) mode, when CPE2 is in transmission mode, i.e. UL (uplink) mode, and vice versa. If they are scheduled in the same time interval, the second customer node CPE2 generates interference to CPE1 , when CPE1 is served in DL by the first access node AN1 , and vice versa, when the second customer node CPE2 is served in DL by the second access node AN2, the first customer node CPE1 instead generates interference to the second customer node CPE2.

The problem above occurs when the access nodes AN1 , AN2 have unsynchronized transmission/reception, i.e. does TDM between transmission and reception to avoid self-interference on the backhaul link. The same problem also occurs in a FDM (Frequency Division Multiplexing) systems where neighboring nodes use different frequencies for transmission/reception to avoid self-interference on the backhaul.

According to the present disclosure, for TDD the system controller module 2 is adapted to schedule transmission and reception time slots for the antenna beams 10a, 10b, 10c; 11a, 11 b, 11 c such that interference between the customer nodes

CPE1 , CPE2 in questions, which are disposed to interfere with each other to a certain degree if one node is transmitting and the other node is receiving at the same frequency, is reduced. More in detail, the system controller module 2 is adapted to schedule transmission or reception time slots such that when the first access node AN1 is transmitting or receiving, the second customer node CPE2 is inactive, and when the second access node AN2 is transmitting or receiving, the first customer node CPE1 is inactive. An example of such scheduling for the first access node AN1 and the second access node AN2 is shown in a first table below:

AN1 AN2

Rt and Rr denote the transmit and receive state of the access nodes AN1 , AN2, respectively. The running number 1 -4 denotes time slots.

Alternatively, should the beam serving instead be frequency-multiplexed between the different connections, i.e. using FDM (Frequency Division Multiplexing) based sharing, a similar solution could be used. A more detailed example for FDM will be described later with reference to Figure 5.

With reference to Figure 2, a schematical view of a second example of a fixed wireless communication system T is shown in a first mode of operation which occurs during a first time interval. Flere the wireless communication system T is in the form of an access-integrated backhaul network where the access nodes AN1 , AN2 have MU-MIMO, Multi-User MIMO (Multiple Input Multiple Output) functionality. A plurality of customer nodes CPE1 , CPE3, CPE5, CPE10, CPE11 , CPE12 are adapted to communicate with the first access node AN1 , and a second plurality of customer nodes CPE2, CPE4, CPE6, CPE7, CPE8, CPE9 are adapted to communicate with a second access node AN2. Each access node AN1 , AN2 is adapted to communicate with the customer nodes CPE1 , CPE3, CPE5, CPE10, CPE11 , CPE12; CPE2, CPE4, CPE6, CPE7, CPE8, CPE9 by means of a corresponding set of antenna beams 10a, 10b, 10c; 11 a, 11 b, 11 c. Generally, each plurality of customer nodes CPE1 , CPE3, CPE5, CPE10, CPE11 , CPE12; CPE2, CPE4, CPE6, CPE7, CPE8, CPE9 comprises a number of customer nodes that exceeds the number of antenna beams in the corresponding set of antenna beams 10a, 10b, 10c; 11a, 11 b, 11 c. Here, there are two customer nodes for each antenna beam.

During the first time interval, the first access node AN1 here serves a twelfth customer node CPE12, a first customer node CPE1 and a third customer node CPE3 simultaneously via corresponding antenna beams 10a, 10b, 10c, and provides backhaul connection to the second access node AN2 simultaneously via a first backhaul antenna beam 10d. The customer nodes CPE12, CPE1 , CPE3 use corresponding customer node beams 7m, 7a, 7c for communication with the first access node AN1 using corresponding customer antenna arrangements 6m, 6a, 6c.

Furthermore, the second access node AN2 serves a fourth customer node CPE4, an eighth customer node CPE8 and a sixth customer node CPE6 simultaneously via corresponding antenna beams 11 a, 11 b, 11 c, and provides backhaul connection to AN1 simultaneously via a second backhaul antenna beam 11 d. The customer nodes CPE4, CPE8, CPE6 use corresponding customer node beams 7d, 7h, 7f for communication with the second access node AN2 using corresponding customer antenna arrangements 6d, 6h, 6f. If the first customer node CPE1 and a second customer node CPE2 that belongs to the second access node AN2 would have been scheduled at the same time, they would have caused mutual interference for the same reason as described in the first example. Here, such interference between the first customer node CPE1 and the second customer node CPE2 is mitigated by scheduling them at different transmission/reception time intervals. The configuration according to Figure 2 described above is present during the first time interval. During a second time interval, there is another configuration. Figure 3 shows a schematical view of the second example the fixed wireless communication system T in a second mode of operation that occurs during the second time interval. Here, the first access node AN1 serves an eleventh customer node CPE11 , a fifth customer node CPE5 and a tenth customer node CPE10 simultaneously via corresponding antenna beams 10a, 10b, 10c, and provides backhaul connection to the second access node AN2 simultaneously via a first backhaul antenna beam 10d. The customer nodes CPE11 , CPE5, CPE10 use corresponding customer node beams 7k, 7e, 7j for communication with the first access node AN1 using corresponding customer antenna arrangements 6k, 6e, 6j.

The second access node AN2 serves a seventh customer node CPE7, an second customer node CPE2 and a ninth customer node CPE9 simultaneously via corresponding antenna beams 11 a, 11 b, 11c, and provides backhaul connection to AN1 simultaneously via a second backhaul antenna beam 11 d. The customer nodes CPE4, CPE8, CPE6 use corresponding customer node beams 7g, 7b, 7i for communication with the second access node AN2 using corresponding customer antenna arrangements 6g, 6b, 6i.

Using the scheduling according to the above, it is avoided to co-schedule the first customer node CPE1 and the second customer node CPE2 during the same time interval, hence the potential interference problem is eliminated. A similar arrangement is applicable for FDM as well.

In order to achieve the above, the following procedure steps can be followed:

1. Assume a scheme where, frequently or upon request (e.g. at network startup), each node measures and transmits information on the interference it experiences when other nodes are active. A node is in this context an access node or a customer node.

2. The nodes report which nodes that should be scheduled.

3. Based on the interference and scheduling information, an access and backhaul beam management unit that is comprised in the system controller module 2 is adapted to determine an optimized beam management schedule that minimizes interference. In other words, it avoids the co-scheduling of any nodes, including beam usage, that may cause too strong interference to each other.

4. Based on the chosen schedule, the access and backhaul beam management unit instructs the affected access nodes to use the new schedule.

5. Go to step 1.

The present disclosure is applicable to an access-integrated backhaul network with interference among nodes, and generally to any type of fixed wireless communication system. By means of coordinated scheduling between backhaul access radio resources and beams, interference is mitigated efficiently.

Figure 4 shows a schematical view of a third example of a fixed wireless communication system 1” that comprises a multi-hop network with four access nodes; a first access node AN1 , a second access node AN2, a third access node AN3 and a fourth access node AN4. The access nodes AN1 , AN2, AN3, AN4 have access-integrated backhaul functionality and single beam transmission/reception. They provide fixed wireless access to user nodes CPE1a, CPE1 b, CPE2a, CPE2b, CPE3a, CPE3b, CPE4a, CPE4b. No antenna beams are shown for the user nodes for reasons of clarity, these antenna beams are of course present. Each access node AN1 , AN2, AN3, AN4 serves two user nodes CPE1a, CPE1 b; CPE2a, CPE2b; CPE3a, CPE3b; CPE4a, CPE4b and provides backhaul connection to the adjacent access nodes. The serving beam is time-multiplexed between the different connections, i.e. TDM based beam switching.

When the first access node AN1 and the third access node AN3 are in transmission mode, and when the second access node AN2 and the fourth access node AN4 are in reception mode, the fourth access node AN4 receives backhaul traffic from the third access node AN3 via a fourth backhaul antenna beam 11 d’, but at the same time the first access node AN1 is also transmitting to the second access node AN2 via a first backhaul antenna beam 3d. Hence interference is generated from the first access node AN1 to the fourth access node AN4 when the fourth backhaul antenna beam 11 d’ is scheduled for reception at the same time as the first backhaul antenna beam 3d is scheduled for transmission.

In accordance with the present disclosure, by means of beam management, the fourth backhaul antenna beam 11 d’ and the first backhaul antenna beam 3d can be scheduled at different time intervals such that interference is mitigated between the first access node AN1 and the fourth access node AN4.

An example of such scheduling for the first access node AN1 and the fourth access node AN4 is shown in a second table below:

AN1 AN4

Rt and Rr denote the transmit and receive state of the access nodes AN1 , AN4, respectively. The running number 1 -3 denotes time slots.

The system controller module 2 is thus adapted to schedule transmission and reception time slots such that when the first access node AN1 is transmitting via the first backhaul antenna beam 10d, the fourth access node AN4 is inactive regarding backhaul communication, and when the fourth access node AN4 is receiving via the fourth backhaul antenna beam 11 d’, the first access node AN1 is inactive regarding backhaul communication.

This means that the inactivity here does not relate to communication with the corresponding user nodes CPE1a, CPE1 b; CPE4a, CPE4b, only to backhaul communication since the interference in this example occurs during backhaul communication. For a corresponding FDM system, the system controller module 2 is adapted to schedule frequency slots such that when the first access node AN1 is transmitting or receiving at one corresponding frequency f₃, U, the fourth access node AN4 is transmitting or receiving at another corresponding frequency f₄, f_3.

Figure 5 shows a schematical view of a fourth example of a fixed wireless communication system 1’” where FDM is used. No antenna beams are shown for reasons of clarity, the antenna beams are of course present. Flere, a first access node AN1 and a second access node AN2 are transmitting and receiving all the time, but they transmit and receive at different frequency bands h, f_2. In such a network, the first access node AN1 is transmitting DL data to a first user node CPE1 at a second frequency f₂ by using beam switching in time and receiving UL data from the first user node CPEi at a first frequency h by the same beam switching. This happens while the second access node AN2, via backhaul connection, is transmitting DL data a second user node CPE2 at the first frequency h and receiving UL data from the second user node CPE2 at the second frequency f₂ also by beam switching.

This generates interference between the user nodes CPE1 , CPE2 with low mutual isolation. This interference can be mitigated by scheduling their beams at different time intervals.

When the first access node AN1 is arranged to communicate the first customer node CPE1 , and the second access node AN2 is arranged to communicate with the second customer node CPE2, the system controller module 2 is adapted to schedule frequency slots such that when the first customer node CPE1 is transmitting or receiving at one corresponding frequency T, f₂, the second customer node CPE2 is transmitting or receiving at another corresponding frequency f₂, T.

As mentioned previously, the FDM operation can also be extended to MU-MIMO operation like was done in the TDM case.

An access and backhaul rescheduling unit mitigates interference and provides more robust link by means of finding an optimized beam management schedule. The present disclosure relates to finding and implementing an optimized backhaul and access radio beam management method through a radio access network that has flexibility to choose different beams for its backhaul and access connections. The beam management method is based on scheduling and interference information obtained from different users.

A centralized access and backhaul beam management unit comprised in a system controller module 2 receives scheduling information from all the access nodes An1 , AN2, AN3, AN4 and interference information from all the nodes, i.e. it knows which beams causes interference to the nodes. The central access and backhaul beam management unit identifies highly interfered nodes. Based on the interference and scheduling information, it finds optimized beam management schemes for different access nodes that achieves good SINR (Signal and Interference to Noise Ratio) and associated improved end-user performance and better use of radio resources. Based on the chosen schemes, it applies the optimized beam forming schemes to the affected access nodes.

The purpose of the backhaul and access rescheduling is to mitigate interference, increase capacity and minimize the degradation of the backhaul and access links, by changing the backhaul and access beams according to an order that reduces the interference in the system.

By means of the present disclosure, an optimized allocation of beams which makes it more reliable, robust against interference and has an improved performance is obtained.

By means of interference mitigation, end-user experience e.g. user data rate will be improved, the users will also experience less outages (dropped connections) and better utilization of radio resources.

According to some aspects, the system controller module 2 is located centrally in the so-called cloud network, or locally in an access point. The advantages with having it located in the cloud network is that the computation and coordination processing can be done in the cloud center. Thus, no extra hardware, memory and power is needed at the node level. The advantage of having it located locally in the access nodes or close to access nodes is that it allows for faster beam management.

With reference to Figure 6, the present disclosure relates to a method for reducing interference in a fixed wireless communication system 1 where the method comprises:

8: Using at least two first type nodes AN1 , AN2, AN3, AN4 for communicating with at least one corresponding second type node CPE1 , CPE2, CPE3, CPE4, CPE5, CPE6, CPE7, CPE8, CPE9, CPE10, CPE11 , CPE12 using at least one corresponding antenna beam 10a, 10b, 10c; 11 a, 11 b, 11 c,

9: Scheduling either transmission and reception time slots for the beams 10a, 10b, 10c; 11 a, 11 b, 11 c, or different frequency slots for the beams 10a, 10b, 10c; 11 a, 11 b, 11 c, such that interference between nodes CPE1 , CPE2; AN1 , AN4, which nodes CPE1 , CPE2; AN1 , AN4 are disposed to interfere with each other to a certain degree if one node is transmitting and the other node is receiving at the same frequency, is reduced. The present disclosure is not limited to the examples above, but may vary freely within the scope of the appended claims. For example, the node 1 may comprise one or more antenna arrangements, each antenna arrangement having a certain coverage which does not have to lie in an azimuth plane, by may lie in any suitable plane, such as for example an elevation plane.

The antenna devices and their corresponding antenna beams can be single or dual polarized.

The access nodes do not have to be adapted for backhaul communication. Generally, the present disclosure does not relate to access nodes and customer nodes, but to first type nodes AN1 , AN2, AN3, AN4, each having a corresponding first type antenna arrangement 3a, 3b, 3c, 3d, and second type nodes CPE1 , CPE2, CPE3, CPE4, CPE5, CPE6, CPE7, CPE8, CPE9, CPE10, CPE11 , CPE12, each having a second type antenna arrangement 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j, 6k, 6m, in a fixed wireless communication system 1.

According to some aspects, the angular directions of the access nodes’ antenna beams 10a, 10b, 10c; 11 a, 11 b, 11 c are either controllable or fixed, according to some further aspects including the backhaul antenna beams 10d, 11 d. According to some aspects, the angular directions of the customer node beams 7a, 7b, 7c, 7d, 7e, 7f, 7g, 7h, 7i, 7j, 7m are either controllable or fixed.

According to some aspects, the system controller module 2 is adapted to schedule transmission and reception time slots for the beams 10a, 10b, 10c; 11 a, 11 b, 1 1 c, as well as different frequency slots for the beams 10a, 10b, 10c; 11 a, 11 b, 11 c, such that interference between the nodes concerned is reduced. In this way, the wireless communication system 1 according to the present disclosure can also be an OFDMA (Orthogonal frequency-division multiple access) system.

According to some aspects, with reference to Figure 7, there is a fixed wireless communication system 1 that comprises:

A using module X8 that is that is configured to use at least two first type nodes AN1 , AN2, AN3, AN4 for communicating with at least one corresponding second type node CPE1 , CPE2, CPE3, CPE4, CPE5, CPE6, CPE7, CPE8, CPE9,

CPE10, CPE11 , CPE12 using at least one corresponding antenna beam 10a, 10b, 10c; 11 a, 11 b, 11 c.

A scheduling module X9 that is configured to schedule transmission and reception time slots for the beams 10a, 10b, 10c; 11 a, 11 b, 11 c, and/or different frequency slots for the beams 10a, 10b, 10c; 11 a, 11 b, 11c, such that interference between nodes CPE1 , CPE2; AN1 , AN4, which nodes CPE1 , CPE2; AN1 , AN4 are disposed to interfere with each other to a certain degree if one node is transmitting and the other node is receiving at the same frequency, is reduced. Generally, the present disclosure relates to a fixed wireless communication system 1 comprising a system controller module 2, at least two first type nodes AN1 , AN2, AN3, AN4, each having a corresponding first type antenna arrangement 3a, 3b, 3c, 3d, and at least two second type nodes CPE1 , CPE2, CPE3, CPE4, CPE5, CPE6, CPE7, CPE8, CPE9, CPE10, CPE11 , CPE12, each having a second type antenna arrangement 6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j, 6k, 6m, where each first type node AN1 , AN2, AN3, AN4 is adapted to communicate with at least one corresponding second type node CPE1 , CPE2, CPE3, CPE4, CPE5, CPE6, CPE7, CPE8, CPE9, CPE10, CPE11 , CPE12 by means of at least one corresponding antenna beam 10a, 10b, 10c; 11 a, 11 b, 11c, wherein the system controller module 2 is adapted to schedule transmission and reception time slots for the beams 10a, 10b, 10c; 11 a, 11 b, 11c, and/or to schedule different frequency slots for the beams 10a, 10b, 10c; 11 a, 11 b, 11 c, such that interference between nodes CPE1 , CPE2; AN1 , AN4, which nodes CPE1 , CPE2; AN1 , AN4 are disposed to interfere with each other to a certain degree if one node is transmitting and the other node is receiving at the same frequency, is reduced. According to some aspects, the angular directions of the beams 10a, 10b, 10c; 11a, 11 b, 11 c are fixed.

According to some aspects, when one first type node AN1 is arranged to communicate with one second type node CPE1 , and another first type node AN2 is arranged to communicate with another second type node CPE2, the system controller module 2 is adapted to schedule transmission and reception time slots such that when said one second type node AN1 is transmitting or receiving, said another second type node CPE2 is inactive, and when said another second type node AN2 is transmitting or receiving, said one second type node is inactive CPE1.

According to some aspects, when one first type node AN1 is arranged to communicate with one second type node CPE1 , and another first type node AN2 is arranged to communicate with another second type node CPE2, the system controller module 2 is adapted to schedule frequency slots such that when said one second type node CPE1 is transmitting or receiving at one corresponding frequency fi, h, said another second type node CPE2 is transmitting or receiving at another corresponding frequency fc, h.

According to some aspects, there is a plurality of second type nodes CPE1 , CPE3, CPE5, CPE10, CPE11 , CPE12 that are adapted to communicate with one first type node AN1 and a second plurality of second type nodes CPE2, CPE4, CPE6, CPE7, CPE8, CPE9 that are adapted to communicate with another first type node AN2, where each first type node AN1 , AN2 is adapted to communicate by means of a corresponding set of antenna beams 10a, 10b, 10c; 11 a, 11 b, 11c, where each plurality of second type nodes CPE1 , CPE3, CPE5, CPE10, CPE11 , CPE12; CPE2, CPE4, CPE6, CPE7, CPE8, CPE9 comprises a number of second type nodes that exceeds the number of antenna beams in the corresponding set of antenna beams 10a, 10b, 10c; 11 a, 11 b, 11 c.

According to some aspects, there is a plurality of first type nodes AN1 , AN2, AN3, AN4, where the first type nodes AN1 , AN2, AN3, AN4 are adapted to communicate with each other by means of backhaul communication via backhaul antenna beams 10d, 11 d, 11d’, where, when one first type node AN1 is arranged to communicate with another first type node AN2, and where a further first type node AN4 is disposed to experience interference from said backhaul communication if said one first type node AN1 is transmitting and said further node AN4 is receiving, the system controller module 2 is adapted to schedule transmission and reception time slots such that when said one first type node AN1 is transmitting via a backhaul antenna beam 10d, said further first type node AN4 is inactive regarding backhaul communication, and when said further first type node AN4 is receiving via a backhaul antenna beam 11 d’, said one first type node AN1 is inactive regarding backhaul communication.

According to some aspects, there is a plurality of first type nodes AN1 , AN2, AN3, AN4, where the first type nodes AN1 , AN2, AN3, AN4 are adapted to communicate with each other via backhaul communication, where, when one first type node AN1 is arranged to communicate with another first type node AN2, and where a further first type node AN4 is disposed to experience interference from said backhaul communication if said one first type node AN1 is transmitting and said further node AN4 is receiving, the system controller module 2 is adapted to schedule frequency slots such that when said one first type node AN1 is transmitting or receiving at one corresponding frequency h,

said further first type node AN4 is transmitting or receiving at another corresponding frequency fi.

Generally, the present disclosure also relates to method for reducing interference in a fixed wireless communication system 1 where the method comprises:

wherein the method comprises:

9: scheduling transmission and reception time slots for the beams 10a, 10b, 10c; l l a, 11 b, 11 c, and/or different frequency slots for the beams 10a, 10b, 10c; 11 a, l l b, 11 c, such that interference between nodes CPE1 , CPE2; AN1 , AN4, which nodes CPE1 , CPE2; AN1 , AN4 are disposed to interfere with each other to a certain degree if one node is transmitting and the other node is receiving at the same frequency, is reduced.

According to some aspects, the angular directions of the beams 10a, 10b, 10c; 11a, 11 b, 11 c are fixed.

According to some aspects, when one first type node AN1 is communicating with one second type node CPE1 , and another first type node AN2 is communicating with another second type node CPE2, the method comprises scheduling transmission and reception time slots such that when said one second type node AN1 is transmitting or receiving, said another second type node CPE2 is inactive, and when said another second type node AN2 is transmitting or receiving, said one second type node is inactive CPE1. According to some aspects, when one first type node AN1 is used for communicating with one second type node CPE1 , and another first type node AN2 is used for communicating with another second type node CPE2, the method comprises scheduling frequency slots such that when said one second type node CPE1 is transmitting or receiving at one corresponding frequency h, fc, said another second type node CPE2 is transmitting or receiving at another corresponding frequency fc, fi.

According to some aspects, there is a first plurality of second type nodes CPE1 , CPE3, CPE5, CPE10, CPE11 , CPE12 that are used for communicating with one first type node AN1 and a second plurality of second type nodes CPE2, CPE4, CPE6, CPE7, CPE8, CPE9 that are used for communicating with another first type node AN2, where each first type node AN1 , AN2 is used for communicating by using a corresponding set of antenna beams 10a, 10b, 10c; 11 a, 11 b, 11c, where each plurality of second type nodes CPE1 , CPE3, CPE5, CPE10, CPE11 , CPE12; CPE2, CPE4, CPE6, CPE7, CPE8, CPE9 comprises a number of second type nodes that exceeds the number of antenna beams in the corresponding set of antenna beams 10a, 10b, 10c; 11 a, 11 b, 11 c.

According to some aspects, there is a plurality of first type nodes AN1 , AN2, AN3, AN4, where the first type nodes AN1 , AN2, AN3, AN4 are used for communicating with each other using backhaul communication via backhaul antenna beams 10a, 11 d, 11d’, where, when one first type node AN1 is used for communicating with another first type node AN2, and where a further first type node AN4 is disposed to experience interference from said backhaul communication if said one first type node AN1 is transmitting and said further node AN4 is receiving, the method comprises scheduling transmission and reception time slots such that when said one first type node AN1 is transmitting via a backhaul antenna beam beam 4, said further first type node AN4 is inactive regarding backhaul communication, and when said further first type node AN4 is receiving via a backhaul antenna beam 11 d’, said one first type node AN1 is inactive regarding backhaul communication.

According to some aspects, there is a plurality of first type nodes AN1 , AN2, AN3, AN4, where the first type nodes AN1 , AN2, AN3, AN4 are used for communicating with each other via backhaul communication, where, when one first type node AN1 is used for communicating with another first type node AN2, and where a further first type node AN4 is disposed to experience interference from said backhaul communication if said one first type node AN1 is transmitting and said further node AN4 is receiving, the method comprises scheduling frequency slots such that when said one first type node AN1 is transmitting or receiving at one corresponding frequency h, f₂, said further first type node AN4 is transmitting or receiving at another corresponding frequency f₂, fi.

Claims

1. A fixed wireless communication system (1 ) comprising a system controller module (2), at least two first type nodes (AN1 , AN2, AN3, AN4), each having a corresponding first type antenna arrangement (3a, 3b, 3c, 3d), and at least two second type nodes (CPE1 , CPE2, CPE3, CPE4, CPE5, CPE6, CPE7, CPE8, CPE9, CPE10, CPE11 , CPE12), each having a second type antenna arrangement (6a, 6b, 6c, 6d, 6e, 6f, 6g, 6h, 6i, 6j, 6k, 6m), where each first type node (AN1 , AN2, AN3, AN4) is adapted to communicate with at least one corresponding second type node (CPE1 , CPE2, CPE3, CPE4, CPE5, CPE6, CPE7, CPE8, CPE9, CPE10, CPE11 , CPE12) by means of at least one corresponding antenna beam (10a, 10b, 10c; 11 a, 11 b, 11 c), wherein the system controller module (2) is adapted to schedule transmission and reception time slots for the beams (10a, 10b, 10c; 11 a, 11 b, 11 c), and/or to schedule different frequency slots for the beams (10a, 10b, 10c; 11 a, 11 b, 11 c), such that interference between nodes (CPE1 , CPE2; AN1 , AN4), which nodes

(CPE1 , CPE2; AN1 , AN4) are disposed to interfere with each other to a certain degree if one node is transmitting and the other node is receiving at the same frequency, is reduced.

2. The communication system according to claim 1 , wherein the angular directions of the beams (10a, 10b, 10c; 11 a, 11 b, 11 c) are fixed.

3. The communication system according to any one of the claims 1 or 2, wherein, when one first type node (AN1 ) is arranged to communicate with one second type node (CPE1 ), and another first type node (AN2) is arranged to communicate with another second type node (CPE2), the system controller module (2) is adapted to schedule transmission and reception time slots such that when said one second type node (AN1 ) is transmitting or receiving, said another second type node (CPE2) is inactive, and when said another second type node (AN2) is transmitting or receiving, said one second type node is inactive (CPE1 ).

4. The communication system according to any one of the claims 1 or 2, wherein, when one first type node (AN1 ) is arranged to communicate with one second type node (CPE1 ), and another first type node (AN2) is arranged to communicate with another second type node (CPE2), the system controller module (2) is adapted to schedule frequency slots such that when said one second type node (CPE1 ) is transmitting or receiving at one corresponding frequency (h, fc), said another second type node (CPE2) is transmitting or receiving at another corresponding frequency (fc, fi).

5. The communication system according to any one of the previous claims, wherein there is a plurality of second type nodes (CPE1 , CPE3, CPE5, CPE10, CPE11 , CPE12) that are adapted to communicate with one first type node (AN1 ) and a second plurality of second type nodes (CPE2, CPE4, CPE6, CPE7, CPE8, CPE9) that are adapted to communicate with another first type node (AN2), where each first type node (AN1 , AN2) is adapted to communicate by means of a corresponding set of antenna beams (10a, 10b, 10c; 11a, 11 b, 11 c), where each plurality of second type nodes (CPE1 , CPE3, CPE5, CPE10, CPE11 , CPE12; CPE2, CPE4, CPE6, CPE7, CPE8, CPE9) comprises a number of second type nodes that exceeds the number of antenna beams in the corresponding set of antenna beams (10a, 10b, 10c; 11 a, 11 b, 11 c).

6. The communication system according to any one of the previous claims, wherein there is a plurality of first type nodes (AN1 , AN2, AN3, AN4), where the first type nodes (AN1 , AN2, AN3, AN4) are adapted to communicate with each other by means of backhaul communication via backhaul antenna beams (1 Od, 11 d, 11 d’), where, when one first type node (AN1 ) is arranged to communicate with another first type node (AN2), and where a further first type node (AN4) is disposed to experience interference from said backhaul communication if said one first type node (AN1 ) is transmitting and said further node (AN4) is receiving, the system controller module (2) is adapted to schedule transmission and reception time slots such that when said one first type node (AN1 ) is transmitting via a backhaul antenna beam (1 Od), said further first type node (AN4) is inactive regarding backhaul communication, and when said further first type node (AN4) is receiving via a backhaul antenna beam (11 d’), said one first type node (AN1 ) is inactive regarding backhaul communication.

7. The communication system according to any one of the claims 1 -5, wherein there is a plurality of first type nodes (AN1 , AN2, AN3, AN4), where the first type nodes (AN1 , AN2, AN3, AN4) are adapted to communicate with each other via backhaul communication, where, when one first type node (AN1 ) is arranged to communicate with another first type node (AN2), and where a further first type node (AN4) is disposed to experience interference from said backhaul communication if said one first type node (AN1 ) is transmitting and said further node (AN4) is receiving, the system controller module (2) is adapted to schedule frequency slots such that when said one first type node (AN1 ) is transmitting or receiving at one corresponding frequency (h, f₂), said further first type node (AN4) is transmitting or receiving at another corresponding frequency (f₂, fi).

8. A method for reducing interference in a fixed wireless communication system (1 ) where the method comprises:

(8) using at least two first type nodes (AN1 , AN2, AN3, AN4) for communicating with at least one corresponding second type node (CPE1 , CPE2, CPE3, CPE4, CPE5, CPE6, CPE7, CPE8, CPE9, CPE10, CPE11 , CPE12) using at least one corresponding antenna beam (10a, 10b, 10c; 11 a, 11 b, 11 c),

wherein the method comprises:

(9) scheduling transmission and reception time slots for the beams (10a,

10b, 10c; 11 a, 11 b, 11 c), and/or different frequency slots for the beams (10a, 10b, 10c; 11a, 11 b, 11 c), such that interference between nodes (CPE1 , CPE2; AN1 , AN4), which nodes (CPE1 , CPE2; AN1 , AN4) are disposed to interfere with each other to a certain degree if one node is transmitting and the other node is receiving at the same frequency, is reduced.

9. The method according to claim 8, wherein the angular directions of the beams (10a, 10b, 10c; 11 a, 11 b, 11 c) are fixed.

10. The method according to any one of the claims 8 or 9, wherein, when one first type node (AN1 ) is communicating with one second type node (CPE1 ), and another first type node (AN2) is communicating with another second type node (CPE2), the method comprises scheduling transmission and reception time slots such that when said one second type node (AN1 ) is transmitting or receiving, said another second type node (CPE2) is inactive, and when said another second type node (AN2) is transmitting or receiving, said one second type node is inactive (CPE1 ).

11. The method according to any one of the claims 8 or 9, wherein, when one first type node (AN1 ) is used for communicating with one second type node (CPE1 ), and another first type node (AN2) is used for communicating with another second type node (CPE2), the method comprises scheduling frequency slots such that when said one second type node (CPE1 ) is transmitting or receiving at one corresponding frequency (h, f₂), said another second type node (CPE2) is transmitting or receiving at another corresponding frequency (f₂, fi).

12. The method according to any one of the claims 8-11 , wherein there is a first plurality of second type nodes (CPE1 , CPE3, CPE5, CPE10, CPE11 , CPE12) that are used for communicating with one first type node (AN1 ) and a second plurality of second type nodes (CPE2, CPE4, CPE6, CPE7, CPE8, CPE9) that are used for communicating with another first type node (AN2), where each first type node (AN1 , AN2) is used for communicating by using a corresponding set of antenna beams (10a, 10b, 10c; 11a, 11 b, 11 c), where each plurality of second type nodes (CPE1 ,

CPE3, CPE5, CPE10, CPE11 , CPE12; CPE2, CPE4, CPE6, CPE7, CPE8, CPE9) comprises a number of second type nodes that exceeds the number of antenna beams in the corresponding set of antenna beams (10a, 10b, 10c; 11 a, 11 b, 11 c).

13. The method according to any one of the previous claims, wherein there is a plurality of first type nodes (AN1 , AN2, AN3, AN4), where the first type nodes (AN1 , AN2, AN3, AN4) are used for communicating with each other using backhaul communication via backhaul antenna beams (10a, 11 d, 11 d’), where, when one first type node (AN1 ) is used for communicating with another first type node (AN2), and where a further first type node (AN4) is disposed to experience interference from said backhaul communication if said one first type node (AN1 ) is transmitting and said further node (AN4) is receiving, the method comprises scheduling transmission and reception time slots such that when said one first type node (AN1 ) is transmitting via a backhaul antenna beam (beam 4), said further first type node (AN4) is inactive regarding backhaul communication, and when said further first type node (AN4) is receiving via a backhaul antenna beam (11 d’), said one first type node (AN1 ) is inactive regarding backhaul communication.

14. The method according to any one of the claims 8-12, wherein there is a plurality of first type nodes (AN1 , AN2, AN3, AN4), where the first type nodes (AN1 , AN2, AN3, AN4) are used for communicating with each other via backhaul communication, where, when one first type node (AN1 ) is used for communicating with another first type node (AN2), and where a further first type node (AN4) is disposed to experience interference from said backhaul communication if said one first type node (AN1 ) is transmitting and said further node (AN4) is receiving, the method comprises scheduling frequency slots such that when said one first type node (AN1 ) is transmitting or receiving at one corresponding frequency (h, f₂), said further first type node (AN4) is transmitting or receiving at another corresponding frequency (f₂, fi).