WO2021000209A1

WO2021000209A1 - Methods and devices for wireless communication

Info

Publication number: WO2021000209A1
Application number: PCT/CN2019/094145
Authority: WO
Inventors: Zhan Zhang; Huaisong Zhu
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2019-07-01
Filing date: 2019-07-01
Publication date: 2021-01-07

Abstract

The present disclosure provides a method (200) at a source network device associated with a source cell and a method (300) at a target network device associated with a target cell. The method (200) comprises: selecting (210), from a plurality of terminal devices served by the source cell, at least one terminal device candidate to be offloaded, based at least on a load of the source cell; determining (220) a target network device associated with a target cell being capable of taking over the at least one terminal device candidate; informing (230) the target network device of the at least one terminal device candidate; and generating (240) common beam weights for the source cell, based on one or more remaining terminal devices in the plurality of terminal devices, with consideration that the selected at least one terminal device candidate is to be offloaded. The method (300) comprises: receiving (310), from a source network device associated with a source cell, information of at least one terminal device candidate that is being served by the source cell and is to be offloaded to the target cell; and generating (320) common beam weights for the target cell, based on one or more terminal devices currently served by the target cell, as well as the at least one terminal device candidate to be offloaded to the target cell.

Description

METHODS AND DEVICES FOR WIRELESS COMMUNICATION

TECHNICAL FIELD

The present disclosure relates to wireless communication, and more particularly, to beamforming in wireless communication.

BACKGROUND

Common beamforming (or cell shaping) has been proposed for both Long Term Evolution (LTE) and 5G New Radio (NR) . With the aid of common beamforming, directional gains of radio propagation can be provided for better cell coverage.

There are different common beamforming approaches. One approach is based on a pre-configured antenna pattern, independent of user equipment (UE) deployment and distribution in reality. The pre-configured antenna pattern can be semi-statically configured by parameters. Such approach of pre-configuration usually does not well fit the deployment and distribution of UEs. As an evolution, another approach will measure directions of UEs based on uplink transmission, and then generate proper beams to focus energy on the directions of UEs respectively.

However, both of the above approaches emphasize a single cell scenario, i.e., they only consider coverage of a single cell, particularly cell edge UE performance. In the single cell scenario, each cell will be “greedy” to absorb UEs, which may result in overloading of the cell, and accordingly block new UEs’ requests on service or admission to network, or tentatively delay the service to some UEs.

SUMMARY

It is an object of the present disclosure to provide a method and a network device, capable of improving cell-loading balance while providing efficient cell-coverage.

In a first aspect of the present disclosure, a method at a source network device associated with a source cell is provided. The method can comprise: selecting, from a plurality of terminal devices served by the source cell, at least one terminal device candidate to be offloaded, based at least on a load of the source cell; determining a target network device associated with a target cell being capable of taking over the at least one terminal device candidate; informing the target network device of the at least one terminal device candidate; and, generating common beam weights for the source cell, based on one or more remaining terminal devices in the plurality of terminal devices, with consideration that the selected at least one terminal device candidate is to be offloaded.

According to an embodiment, the method can further comprise: assigning the at least one terminal device candidate with a priority for generating common beam weights for the target cell, prior to informing the target network device of the at least one terminal device candidate. Informing the target network device of the at least one terminal device candidate can comprise informing the target network device of the assigned priority of the at least one terminal device candidate.

According to an embodiment, generating the common beam weights for the source cell can comprise: assigning each of the one or more remaining terminal devices with a priority for generating the common beam weights for the source cell.

According to an embodiment, generating the common beam weights for the source cell can further comprise: acquiring channel information between each of the one or more remaining terminal devices and the source network device; and, generating the common beam weights for the source cell, based on the channel information and the assigned priority of each of the one or more remaining terminal devices.

According to an embodiment, the source network device associated with the source cell is configurable for controlling a multiple input multiple output (MIMO) antenna system, and the method can further comprise controlling the MIMO antenna system to form a common beam for the source cell, based on the generated common beam weights.

In a second aspect of the present disclosure, a method at a target network device associated with a target cell is provided. The method can comprise: receiving, from a source network device associated with a source cell, information of at least one terminal device candidate that is being served by the source cell and is to be offloaded to the target cell; and, generating common beam weights for the target cell, based on one or more terminal devices currently served by the target cell, as well as the at least one terminal device candidate to be offloaded to the target cell.

According to an embodiment, the information of the at least one terminal device candidate to be offloaded to the target cell can comprise an assigned first priority for generating the common beam weights for the target cell of the at least one terminal device candidate.

According to an embodiment, the method can further comprise: assigning the at least one terminal device candidate to be offloaded to the target cell with a first priority for generating the common beam weights for the target cell, prior to generating the common beam weights for the target cell.

According to an embodiment, the method can further comprise: assigning each of the one or more terminal devices currently served by the target cell with a second priority for generating the common beam weights for the target cell, prior to generating the common beam weights for the target cell.

According to an embodiment, generating the common beam weights for the target cell can comprise: acquiring first channel information between the at least one terminal device candidate and the target network device, and second channel information between each of the one or more terminal devices currently served by the target cell and the target network device; and, generating the common beam weights for the target cell, based on the first and the second channel information, the first priority of the at least one terminal device candidate, and the second priority of each of the one or more terminal devices currently served by the target cell.

According to an embodiment, the target network device associated with the target cell is configurable for controlling a multiple input multiple output (MIMO) antenna system, and the method can further comprise: controlling the MIMO antenna system to form a common beam for the target cell, based on the generated common beam weights.

In a third aspect of the present disclosure, a source network device associated with a source cell is provided. The source network device can comprise a processor and a memory configured to store instructions. The instructions, when executed by the processor, cause the source network device to perform the method according to the above first aspect.

In a fourth aspect of the present disclosure, a target network device associated with a target cell is provided. The target network device can comprise a processor and a memory configured to store instructions. The instructions, when executed by the processor, cause the target network device to perform the method according to the above second aspect.

In a fifth aspect of the present disclosure, a computer readable storage medium is provided. The computer readable storage medium has instructions stored thereon, which, when executed by a processor of a source network device associated with a source cell, cause the source network device to perform the method according to the above first aspect.

In a sixth aspect of the present disclosure, a computer readable storage medium is provided. The computer readable storage medium has instructions stored thereon, which, when executed by a processor of a target network device associated with a target cell, cause the target network device to perform the method according to the above second aspect.

With the embodiments of the present disclosure, it is possible to share a load of an overloaded cell by another cell with a relatively lower load, and adjust common beamforming accordingly, thereby enabling cell-loading balance to be improved and efficient cell-coverage to be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages will be more apparent from the following description of embodiments with reference to the figures, in which:

Figs. 1A and 1B are schematic diagrams illustrating an existing common beamforming approach;

Fig. 2 is a flowchart illustrating a method at a source network device according to embodiments of the present disclosure;

Fig. 3 is a flowchart illustrating a method at a target network device according to embodiments of the present disclosure;

Figs. 4A and 4B are schematic diagrams illustrating a common beamforming approach according to embodiments of the present disclosure;

Fig. 5 is a block diagram illustrating an exemplary source network device according to embodiments of the present disclosure;

Fig. 6 is a block diagram illustrating an exemplary apparatus that can perform the method of Fig. 2 according to embodiments of the present disclosure;

Fig. 7 is a block diagram illustrating an exemplary target network device according to embodiments of the present disclosure;

Fig. 8 is a block diagram illustrating an exemplary apparatus that can perform the method of Fig. 3 according to embodiments of the present disclosure;

Fig. 9 schematically illustrates a telecommunication network connected via an intermediate network to a host computer;

Fig. 10 is a generalized block diagram of a host computer communicating via a base station with a user equipment over a partially wireless connection; and

Figs. 11 to 14 are flowcharts illustrating methods implemented in a communication system including a host computer, a base station and a user equipment.

DETAILED DESCRIPTION

As used herein, the term "wireless communication network" refers to a network following any suitable wireless communication standards, such as NR, LTE-Advanced (LTE-A) , LTE, Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , and so on. Furthermore, the communications between a terminal device and a network device in the wireless communication network may be performed according to any suitable generation communication protocols, including, but not limited to, Global System for Mobile Communications (GSM) , Universal Mobile Telecommunications System (UMTS) , LTE, and/or other suitable 1G, 2G, 2.5G, 2.75G, 3G, 4G, 4.5G, 5G, 6G communication protocols; wireless local area network (WLAN) standards, such as the IEEE 802.11 standards; and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax) , Bluetooth, and/or ZigBee standards, and/or any other protocols either currently known or to be developed in the future.

The term "network device" or “network node” refers to a device in a communication network via which a terminal device accesses the network and receives services therefrom. Examples of the network device may include a base station (BS) , an access point (AP) , or any other suitable device in the wireless communication network. The BS may be, for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a next generation NodeB (gNodeB or gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , a remote radio head (RRH) , a relay, a low power node such as a femto, a pico, and so forth. Yet further examples of the network device may include multi-standard radio (MSR) radio equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs) , base transceiver stations (BTSs) , transmission points, transmission nodes, positioning nodes or the like. More generally, however, the network device may represent any suitable device (or group of devices) capable, configured, arranged, and/or operable to enable and/or provide a terminal device access to the wireless communication network or to provide some service to a terminal device that has access to the wireless communication network.

The term "terminal device" refers to any end device that can access a wireless communication network and receive services therefrom. By way of example and not limitation, the terminal device may refer to a mobile terminal, a user equipment (UE) , or other suitable devices. The UE may be, for example, a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) . The terminal device may include, but not limited to, portable computers, desktop computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, mobile phones, cellular phones, smart phones, tablets, personal digital assistants (PDAs) , wearable devices, vehicle-mounted wireless terminal devices, wireless endpoints, or the like.

In the following description, the terms "terminal device" , "terminal" , "user equipment" and "UE" may be used interchangeably. As one example, a terminal device may represent a UE configured for communication in accordance with one or more communication standards promulgated by the 3rd Generation Partnership Project (3GPP) , such as 3GPP's GSM, UMTS, LTE, and/or 5G standards. As used herein, a "user equipment" or "UE" may not necessarily have a "user" in the sense of a human user who owns and/or operates the relevant device. In some embodiments, a terminal device may be configured to transmit and/or receive information without direct human interaction. For instance, a terminal device may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the wireless communication network. As a further example, a UE may represent a device that is intended for sale to, or operation by, a human user but that may not initially be associated with a specific human user.

As yet another example, in an Internet of Things (IoT) scenario, a terminal device may represent a machine or other device that performs monitoring, sensing and/or measurements, and transmits the results of such monitoring, sensing and/or measurements to another terminal device and/or network equipment. The terminal device may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as a machine-type communication (MTC) device.

As used herein, a downlink transmission refers to a transmission from a network device to a terminal device, and an uplink transmission refers to a transmission in an opposite direction.

References in the specification to "one embodiment, " "an embodiment, " "an example embodiment, " and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms "first" and "second" etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be liming of example embodiments. As used herein, the singular forms "a" , "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" , "comprising" , "has" , "having" , "includes" and/or "including" , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

The existing approaches of common beamforming only consider coverage of a single cell, particularly cell edge UE performance. For example, a network device, such as gNB or eNB, can detect UE’s location and focus more energy on the UE’s direction in a Down Link (DL) coverage common beamforming. With help of such common beam change, the UE can receive a better common beam signal strength.

Take Figs. 1A and 1B as an example. Figs. 1A and 1B are schematic diagrams illustrating an existing common beamforming approach. As shown in Fig. 1A, a network device 10 is associated with a cell 100. The cell 100 serves a plurality of

UEs

110, 120, 130, 140, 150 and 160, and comprises a first area 100_1 with high common beam signal strength, and a second area 100_2 with relatively lower common beam signal strength.

UEs

110, 120 and 130 are covered by the first area 100_1, while

UEs

140, 150 and 160 are covered by the second area 100_2. To improve performance of

UEs

140, 150 and 160 at the edge of the cell 100, the network device 10 can detect locations of

UEs

140, 150 and 160 and focus more energy on directions of

UEs

140, 150 and 160 in common beamforming. After such common beam change,

UEs

140, 150 and 160 can receive better common beam signal strength than before. As shown in Fig. 1B, after the common beam change,

UEs

140, 150 and 160 are covered by the first area 100_1 with high common beam signal strength. In other words, the “shape” of the first area 100_1 with high signal strength has been changed so that it can cover more UEs, such as

UEs

140, 150 and 160.

The existing common beamforming approaches, such as the approach as shown in Figs. 1A and 1B, try to address the issue of coverage of cell edge UEs. However, these approaches will make an independent decision per cell, i.e., only consider cell coverage of a single cell. In the single cell scenario, each cell will be “greedy” to absorb more UEs at the edge of the cell, as shown in Figs. 1A and 1B, which may result in overloading of the cell, and accordingly block new UEs’ requests on service or admission to network, or tentatively delay the service to some UEs. Therefore, it may be advantageous to improve not only cell coverage, but also cell overloading.

Fig. 2 is a flowchart illustrating a method 200 according to embodiments of the present disclosure. The method 200 can be performed at a source network device, e.g., an eNB or a gNB, which is not limited herein. The source network device is associated with a source cell.

At block 210, at least one terminal device candidate to be offloaded is selected from a plurality of terminal devices served by the source cell, based at least on a load of the source cell.

On the basis of at least the load of the source cell, one or more terminal device candidates to be offloaded can be selected from the plurality of terminal devices served by the source cell. For example, if the source cell load is larger than a predetermined load threshold, or the difference between the source cell load and a neighboring cell load is larger than a predetermined load difference threshold, the one or more terminal device candidates to be offloaded can be selected from the plurality of terminal devices served by the source cell.

The load of a cell can be represented by Physical Resource Block (PRB) utilization ratio, the number of terminal devices served by the cell, or other Key Performance Indicators (KPIs) , such as time delay of data transmission, which is not limited herein. For example, if the time/frequency resource utilization ratio of the source cell is larger than 90%, the at least one terminal device candidate to be offloaded can be selected from the plurality of terminal devices.

Upon selecting or determining which terminal device is to be offloaded, one or more of many factors can be considered, in addition to the load of the source cell. These factors can comprise, but not limited to, a traffic load of a terminal device, a Reference Signal Received Power (RSRP) or Layer 1-Reference Signal Received Power (L1-RSRP) of the terminal device to the source network device and/or to a network device associated with a neighboring cell, a pathloss of the terminal device to the source network device and/or to the network device associated with the neighboring cell, a Quality of Service (QoS) of the terminal device, a load of the neighboring cell, a Signal to Noise Ratio (SNR) of the terminal device to the source network device, a Signal to Interference plus Noise Ratio (SINR) of the terminal device to the source network device, and a Signal to Interference Ratio (SIR) of the terminal device to the source network device, etc.

For example, if the traffic load of a certain UE is larger than a predetermined traffic load threshold, this UE can be selected as a candidate. As another example, if the RSRP or L1-RSRP of a certain UE to the source network device is smaller than a predetermined power threshold, the UE can be selected as a candidate for offloading. Alternatively, the terminal device candidate can be selected according to pathloss instead of RSRP or L1-RSRP. For example, if the pathloss of a certain UE to the source network device is larger than a predetermined pathloss threshold, the UE can be selected as a candidate. The RSRP, L1-RSRP or pathloss can be Down Link (DL) based or Up Link (UL) based.

Upon selecting or determining which terminal device is to be offloaded, cell edge terminal device criteria can be considered as another option. For example, if the difference between the RSRP or L1-RSRP of a terminal device to the source network device and the RSRP or L1-RSRP of the terminal device to a network device associated with a neighboring cell is smaller than a predetermined power difference threshold, the terminal device can be selected as a candidate for offloading, as the power difference smaller than the predetermined power difference threshold may indicate that the terminal device is located at the edge of the source cell and between the source cell and the neighboring cell. Therefore, the terminal device may be offloaded from the source cell.

At block 220, a target network device associated with a target cell is determined, the target network device being capable of taking over the at least one terminal device candidate.

After selecting the at least one terminal device candidate to be offloaded from the source cell, the target network device associated with the target cell for taking over the at least one terminal device candidate can be determined. For example, the source network device can evaluate the load (s) of one or more neighboring cells, and determine a network device associated with a neighboring cell as the target network device, if the network device associated with the neighboring cell is capable of taking over the at least one terminal device candidate.

At block 230, the target network device is informed of the at least one terminal device candidate.

Once the target network device associated with the target cell is determined, the target network device can be informed of the at least one terminal device candidate to be offloaded to the target cell. For example, the target network device can be informed of Identity (ID) of the at least one terminal device candidate to be offloaded, so that it will know which terminal device is to be offloaded from the source cell.

In an embodiment, the method 200 can further comprise, assigning the at least one terminal device candidate with a priority for generating common beam weights for the target cell, prior to informing the target network device of the at least one terminal device candidate. And informing the target network device of the at least one terminal device candidate can comprise, informing the target network device of the assigned priority of the at least one terminal device candidate.

By assigning the at least one terminal device candidate with the priority for generating common beam weights for the target cell and informing the target network device of the assigned priority, common beam weights for the target cell can be generated by taking account of the priority. For the priority of a terminal device candidate, a larger value represents a higher priority, and accordingly, there will be more weight for the terminal device candidate in common beamforming for the target cell. Therefore, the target cell can provide a better coverage for the terminal device candidate.

The priority of the terminal device candidate can be determined based on one or more of many factors. These factors can comprise, but not limited to, the load of the source cell, the traffic load of the terminal device candidate, the RSRP or L1-RSRP of the terminal device candidate to the target network device, the pathloss of the terminal device candidate to the target network device, the QoS of the terminal device candidate, the load of the target cell, the SNR of the terminal device candidate to the target network device, the SINR of the terminal device candidate to the target network device, and the SIR of the terminal device candidate to the target network device, etc. The priority of the terminal device candidate can be determined, depending on any one of these factors or any combination of the factors, for example.

For example, a higher traffic load or QoS of the terminal device candidate will result in a larger value of the priority. And a lower load of the target cell will result in a larger value of the priority. For the RSRP or L1-RSRP of the terminal device candidate to the target network device, the smaller the RSRP or L1-RSRP is, the larger the priority value will be. For the pathloss of the terminal device candidate to the target network device, the larger the pathloss is, the larger the priority value will be.

One way of determining a priority α of a terminal device candidate u, for generating common beam weights for a target cell B, is as follows.

α ^[Bu] = F1*Source_Cell_PRB ratio * max {UE_PRB_ratio, min_UE_PRB_ratio } (I)

In the equation (I) , Source_Cell_PRB ratio is PRB utilization ratio of the source cell, and UE_PRB_ratio is percentage of PRB utilization of the source cell by the terminal device candidate. To prevent a terminal device with very low traffic load from being ignored by the common beamforming for the target cell, a lower bound of UE_PRB_ratio is preset, which is represented by min_UE_PRB_ratio. The value of min_UE_PRB_ratio can be 0.1%, for example. F1 is a preset adjustment factor. The value of F1 can be 200, for example.

It should be noted that, although the priority of the terminal device candidate can be determined based on the above equation (I) , such an approach is only an example. Other ways of determining the priority can also be used without limitation.

At block 240, common beam weights for the source cell is generated, based on one or more remaining terminal devices in the plurality of terminal devices, with consideration that the selected at least one terminal device candidate is to be offloaded.

In consideration that the selected at least one terminal device candidate is to be offloaded to the target cell and will not be served by the source cell, the common beam weights for the source cell can be generated based on the one or more remaining terminal devices in the plurality of terminal devices. In other words, the common beam weights for the source cell can be generated, based on the one or more remaining terminal devices, which do not include the selected at least one terminal device candidate to be offloaded.

In an embodiment, generating the common beam weights for the source cell can comprise assigning each of the one or more remaining terminal devices with a priority for generating the common beam weights for the source cell.

For the priority of the remaining terminal device, a larger value represents a higher priority, and accordingly, there will be more weight for the terminal device in common beamforming for the source cell. Therefore, the source cell can provide a better coverage for the remaining terminal device.

The priority of the remaining terminal device can be determined based on one or more of many factors. These factors can comprise, but not limited to, the traffic load of the remaining terminal device, the RSRP or L1-RSRP of the remaining terminal device to the source network device, the pathloss of the remaining terminal device to the source network device, the QoS of the remaining terminal device, the SNR of the remaining terminal device to the source network device, the SINR of the remaining terminal device to the source network device, and the SIR of the remaining terminal device to the source network device, etc. The priority of the remaining terminal device can be determined, depending on any one of these factors or any combination of the factors, for example.

For example, a higher traffic load or QoS of the remaining terminal device will result in a larger value of the priority. For the RSRP or L1-RSRP of the remaining terminal device to the source network device, the smaller the RSRP or L1-RSRP is, the larger the priority value will be. For the pathloss of the remaining terminal device to the source network device, the larger the pathloss is, the larger the priority value will be.

One way of determining a priority α of a remaining terminal device u, for generating common beam weights for a source cell A, is as follows.

α ^[Au] = F2 *max {UE_PRB_ratio, min_UE_PRB_ratio } (II)

In the equation (II) , UE_PRB_ratio is percentage of PRB utilization of the source cell by the remaining terminal device. To prevent a terminal device with very low traffic load from being ignored by common beamforming for the source cell, a lower bound of UE_PRB_ratio is preset, which is represented by min_UE_PRB_ratio. The value of min_UE_PRB_ratio can be 0.1%, for example. F2 is a preset adjustment factor. The value of F2 can be 10, for example.

It should be noted that, although the priority of the remaining terminal device can be determined based on the above equation (II) , such an approach is only an example. Other ways of determining the priority can also be used without limitation.

If each of the one or more remaining terminal devices is assigned with a priority for generating the common beam weights for the source cell, the common beam weights for the source cell can be generated based on such priority. In an embodiment, generating the common beam weights for the source cell can further comprise: acquiring channel information between each of the one or more remaining terminal devices and the source network device; and, generating the common beam weights for the source cell, based on the channel information and the assigned priority of each of the one or more remaining terminal devices. As described above, by taking account of the priority of each remaining terminal device in common beamforming of the source cell, the source cell will provide a better coverage for the remaining terminal device.

The channel information between each of the one or more remaining terminal devices and the source network device can be acquired by measuring channel between each remaining terminal device and the source network device. For example, the source network device associated with the source cell can configure each remaining terminal device to send out (Sounding Reference Signal) SRS or Demodulation Reference Signal (DMRS) signal, and measure SRS or DMRS signal from each remaining terminal device to acquire the channel information from channel impulse response.

The channel information between each of the one or more remaining terminal devices and the source network device can be represented by a channel information matrix. It is assumed that, in a plurality of terminal devices served by a source cell A, terminal devices k1, k2.... ky are remaining terminal devices, which do not include the at least one terminal device candidate to be offloaded. The remaining terminal devices k1, k2.... ky constitute a set of remaining terminal devices, i.e., set _{a_A}= {k1, k2…ky} . The channel information between a remaining terminal device k and a source network device associated with the source cell A can be represented by a channel information matrix H ^[Ak] , and the matrix H ^[Ak] can be obtained by measuring channel between each physical antenna or antenna port of the source cell A and each physical antenna of the remaining terminal device k. It is assumed that the number of physical antennas or antenna ports in the source cell A is M and the number of the physical antennas of the remaining terminal device k is N. The matrix H ^[Ak] will be a N × M matrix, with each element representing channel information between a physical antenna or antenna port of the source cell A and a corresponding physical antenna of the remaining terminal device k.

After acquiring the channel information between each of the one or more remaining terminal devices and the source network device, the common beam weights for the source cell can be generated based on the channel information and the assigned priority of each of the one or more remaining terminal devices.

For example, the common beam weights

for the source cell A can be generated by following steps.

a) Define a matrix

where α ^[Ak] is the assigned priority of the remaining terminal device k, and

is a normalized matrix of the channel information matrix H ^[Ak] .

can be obtained as follows:

The matrix R ^[A] can reflect combined spatial information of the source cell A.

b) Make matrix factorization of the matrix R ^[A] :

R ^[A] = Q ^[A] (D ^[A] ) ² (Q ^[A] ) ^H ,

where D ^[A] is a diagonal matrix.

c) Obtain a vector S ^[A] for the source cell A:

S ^[A] =diag (D ^[A] ) ,

The elements of the vector S ^[A] are elements on the diagonal of the diagonal matrix D ^[A] , and all of the elements can be positive real numbers.

d) Generate the common beam weights

for the source cell A:

In the above step a) , the matrix

can be replaced by the matrix H ^[Ak] , i.e., without normalization of the matrix H ^[Ak] . If the matrix H ^[Ak] is used, the matrix R ^[A] can be defined as: R ^[A] = ∑ _{k∈set_a_A}α ^[Ak] ( (H ^[Ak] ) ^H H ^[Ak] ) , while other steps b) –d) can be the same.

Alternatively, the common beam weights for the source cell can be generated, without relying on the priority of the remaining terminal device (s) . For example, generating the common beam weights for the source cell can comprise: acquiring channel information between each of the one or more remaining terminal devices and the source network device; and, generating the common beam weights for the source cell, based on the acquired channel information.

The common beam weights

for the source cell A can be generated by following steps, for example.

a) Define a matrix

where

is a normalized matrix of the channel information matrx H ^[Ak] .

b) Make matrix factorization of the matrix R ^[A, k] :

R ^[A, k] = Q ^[A, k] (D ^[A, k] ) ² (Q ^[A, k] ) ^H,

where D ^[A, k] is a diagonal matrix.

c) Obtain a vector S ^[A, k] :

S ^[A, k] =diag (D ^[A, k] ) ,

The elements of the vector S ^[A, k] are elements on the diagonal of the diagonal matrix D ^[A, k] , and all of the elements can be positive real numbers.

d) Determine the common beam weight

for the remaining terminal device k:

where

is in a vector format.

e) Generate the common beam weights

for the source cell A:

The common beam weights

is an average of the common beam weights for all of the remaining terminal devices k1, k2.... ky.

In the above step a) , the matrix

can be replaced by the matrix H ^[Ak] , i.e., without normalization of the matrix H ^[Ak] . If the matrix H ^[Ak] is used, the matrix R ^[A] can be defined as: R ^[A, k] = ( (H ^[Ak] ) ^H H ^[Ak] ) , while other steps b) –e) can be the same.

The generated common beam weights for the source cell can be used for forming a common beam for the source cell. In an embodiment, the source network device associated with the source cell is configurable for controlling a multiple input multiple output (MIMO) antenna system, and the method 200 can further comprise controlling the MIMO antenna system to form a common beam for the source cell, based on the generated common beam weights. Data rates can be improved by use of a MIMO antenna system. The MIMO antenna system can be a Massive MIMO antenna system, for example.

With the above method 200 according to embodiments of the present disclosure, it is possible to share a load of an overloaded cell (such as source cell) by another cell (such as target cell) with a relatively lower load, and adjust common beamforming accordingly, thereby enabling cell-loading balance to be improved and efficient cell-coverage to be provided.

Fig. 3 is a flowchart illustrating a method 300 according to embodiments of the present disclosure. The method 300 can be performed at a target network device, e.g., an eNB or a gNB, which is not limited herein. The target network device is associated with a target cell.

At block 310, information of at least one terminal device candidate is received from a source network device associated with a source cell. The at least one terminal device candidate is being served by the source cell and is to be offloaded to the target cell.

For the target network device associated with the target cell, information of the at least one terminal device candidate, that is being served by the source cell and is to be offloaded to the target cell, can be received. For example, the information can comprise Identity (ID) of the at least one terminal device candidate to be offloaded, so that the target network device will know which terminal device is to be offloaded from the source cell.

In an embodiment, the information of the at least one terminal device candidate to be offloaded to the target cell can comprise an assigned first priority for generating the common beam weights for the target cell of the at least one terminal device candidate.

As described above, prior to informing the target network device of the at least one terminal device candidate to the offloaded, the source network device can assign the at least one terminal device candidate with a priority for generating common beam weights for the target cell. If the priority of the at least one terminal device candidate to be offloaded to the target cell has been assigned by the source network device, the information of the at least one terminal device candidate, received from the source network device, can comprise the assigned priority. As described above, for the priority of a terminal device candidate, a larger value represents a higher priority, and accordingly, there will be more weight for the terminal device candidate in common beamforming for the target cell. Therefore, the target cell will provide a better coverage for the terminal device candidate.

At block 320, common beam weights for the target cell are generated, based on one or more terminal devices currently served by the target cell, as well as the at least one terminal device candidate to be offloaded to the target cell.

Since terminal devices to be served by the target cell comprise not only the one or more terminal devices currently served by the target cell, but also the at least one terminal device candidate to be offloaded to the target cell, the common beam weights for the target cell can be generated, based on the one or more terminal devices currently served by the target cell as well as the at least one terminal device candidate to be offloaded to the target cell.

Instead of assigning a terminal device candidate with a priority for generating common beam weights for the target cell by the source network device, the priority of the terminal device candidate can be assigned by the target network device. In an embodiment, the method 300 can further comprise assigning the at least one terminal device candidate to be offloaded to the target cell with a first priority for generating the common beam weights for the target cell, prior to generating the common beam weights for the target cell.

As described above, the first priority of the at least one terminal device candidate can be determined based on one or more of many factors. These factors can comprise, but not limited to, the load of the source cell, the traffic load of the terminal device candidate, the RSRP or L1-RSRP of the terminal device candidate to the target network device, the pathloss of the terminal device candidate to the target network device, the QoS of the terminal device candidate, the load of the target cell, the SNR of the terminal device candidate to the target network device, the SINR of the terminal device candidate to the target network device, and the SIR of the terminal device candidate to the target network device, etc. The first priority of the terminal device candidate can be determined, depending on any one of these factors or any combination of the factors, for example.

In an embodiment, the method 300 can further comprise assigning each of the one or more terminal devices currently served by the target cell with a second priority for generating the common beam weights for the target cell, prior to generating the common beam weights for the target cell. In other words, in addition to the at least one terminal device candidate to be offloaded to the target cell, each terminal device currently served by the target cell can be assigned with a priority as well.

If the at least one terminal device candidate to be offloaded to the target cell has been assigned with the first priority and each terminal device currently served by the target cell has been assigned with the second priority, the common beam weights for the target cell can be generated based on the first priority and the second priority. In an embodiment, generating the common beam weights for the target cell can comprise: acquiring first channel information between the at least one terminal device candidate and the target network device, and second channel information between each of the one or more terminal devices currently served by the target cell and the target network device; and, generating the common beam weights for the target cell, based on the first and the second channel information, the first priority of the at least one terminal device candidate, and the second priority of each of the one or more terminal devices currently served by the target cell. By taking account of the priority of the at least one terminal device candidate to be offloaded to the target cell as well as the priority of each terminal device currently served by the target cell in common beamforming of the target cell, the target cell will provide a better coverage for both the at least one terminal device candidate to be offloaded to the target cell and each terminal device currently served by the target cell.

The first channel information between the at least one terminal device candidate to be offloaded to the target cell and the target network device can be acquired by measuring channel between the at least one terminal device candidate and the target network device. For example, the source network device associated with the source cell can configure the at least one terminal device candidate to send out SRS or DMRS signal, and exchange SRS or DMRS configuration information with the target network device associated with the target cell. Therefore, the target network device can measure SRS or DMRS signal from the at least one terminal device candidate, to acquire the first channel information from channel impulse response.

The first channel information between the at least one terminal device candidate and the target network device can be represented by a first channel information matrix. It is assumed that there are terminal device candidates j1, j2.... jx, which are to be offloaded to a target cell B from a source cell A and constitute a set of terminal device candidates, i.e., set _{b_A}= {j1, j2…jx} . The first channel information between a terminal device candidate j and the target network device can be represented by a first channel information matrix H ^[Aj] , and the matrix H ^[Aj] can be obtained by measuring channel between each physical antenna or antenna port of the target cell B and each physical antenna of the terminal device candidate j. It is assumed that the number of physical antennas or antenna ports in the target cell B is R and the number of the physical antennas of the terminal device candidate j is S. The matrix H ^[Aj] can be a S × R matrix, with each element representing channel information between a physical antenna or antenna port of the target cell B and a corresponding physical antenna of the terminal device candidate j.

The second channel information between each of the one or more terminal devices currently served by the target cell and the target network device can be acquired by measuring channel between each terminal device currently served by the target cell and the target network device. For example, the target network device associated with the target cell can configure each terminal device currently served by the target cell to send out SRS or DMRS signal, and measure SRS or DMRS signal from each terminal device currently served by the target cell, to acquire the second channel information from channel impulse response.

The second channel information between each terminal device currently served by the target cell and the target network device can be represented by a second channel information matrix. It is assumed that there are terminal devices q1, q2.... qz, which are currently served by the target cell B and constitute a set of terminal devices currently served by the target cell B, i.e., set _{b_B}= {q1, q2 …qz} . The second channel information between a terminal device q currently served by the target cell B and the target network device can be represented by a second channel information matrix H ^[Bq] , and the matrix H ^[Bq] can be obtained by measuring channel between each physical antenna or antenna port of the target cell B and each physical antenna of the terminal device q. It is assumed that the number of physical antennas or antenna ports in the target cell B is R and the number of the physical antennas of the terminal device q is W. The matrix H ^[Bq] can be a W × R matrix, with each element representing channel information between a physical antenna or antenna port of the target cell B and a corresponding physical antenna of the terminal device q currently served by the target cell B.

After acquiring the first and the second channel information, the common beam weights for the target cell can be generated based on the first and the second channel information, the first priority of the at least one terminal device candidate to be offloaded to the target cell, and the second priority of each terminal device currently served by the target cell.

For example, the common beam weights

for the target cell B can be generated by following steps.

a) Define a matrix

where α ^[Aj] is the first priority, α ^[Bq] is the second priority,

is a normalized matrix of the first channel information matrix H ^[Aj] , and

is a normalized matrix of the second channel information matrix H ^[Bq] .

The matrix R ^[B] can reflect combined spatial information of the target cell B.

b) Make matrix factorization of the matrix R ^[B] :

R ^[B] = Q ^[B] (D ^[B] ) ² (Q ^[B] ) ^H ,

where D ^[B] is a diagonal matrix.

c) Obtain a vector S ^[B] for the target cell B:

S ^[B] =diag (D ^[B] ) ,

The elements of the vector S ^[B] are elements on the diagonal of the diagonal matrix D ^[B] , and all of the elements can be positive real numbers.

d) Generate the common beam weights

for the target cell B:

In the above step a) , the matrix

and the matrix

can be replaced by the matrix H ^[Aj] and the matrix H ^[Bq] , respectively, i.e., without normalization of the matrix H ^[Aj] and the matrix H ^[Bq] .

If the matrix H ^[Aj] and the matrix H ^[Bq] are used, the matrix R ^[B] can be defined as:

while other steps b) –d) can be the same.

Alternatively, the common beam weights for the target cell can be generated, without relying on the first priority and the second priority. For example, generating the common beam weights for the target cell can comprise: acquiring channel information between each of the at least one terminal device candidate to be offloaded to the target cell as well as the one or more terminal devices currently served by the target cell and the target network device; and, generating the common beam weights for the target cell, based on the acquired channel information.

The generated common beam weights for the target cell can be used for forming a common beam for the target cell. In an embodiment, the target network device associated with the target cell is configurable for controlling a multiple input multiple output (MIMO) antenna system, and the method 300 can further comprise controlling the MIMO antenna system to form a common beam for the target cell, based on the generated common beam weights. Data rates can be improved by use of a MIMO antenna system. The MIMO antenna system can be a Massive MIMO antenna system, for example.

With the above method 300 according to embodiments of the present disclosure, it is possible to share a load of an overloaded cell (such as source cell) by another cell (such as target cell) with a relatively lower load, and adjust common beamforming accordingly, thereby enabling cell-loading balance to be improved and efficient cell-coverage to be provided.

Figs. 4A and 4B are schematic diagrams illustrating a common beamforming approach according to embodiments of the present disclosure.

As shown in Fig. 4A, a source network device 400a is associated with a source cell 400A serving a plurality of terminal devices, such as UEs 410a, 420a, 430a, 440a, 450a and 460a. The source cell 400A comprises a first area 400A_1 with high common beam signal strength, and a second area 400A_2 with relatively lower common beam signal strength. UEs 410a, 420a and 430a are covered by the first area 400A_1, while

UEs

440a, 450a and 460a are covered by the second area 400A_2.

From UEs 410a, 420a, 430a, 440a, 450a and 460a served by the source cell 400A,

UE candidates

440a and 450a to be offloaded are selected, for example, based at least on a load of the source cell 400A.

After

UE candidates

440a and 450a are selected, a target network device 400b associated with a target cell 400B is determined. The target network device 400b is capable of taking over the selected

UE candidates

440a and 450a.

Once the target network device 400b is determined, the target network device 400b is informed of

UE candidates

440a and 450a. Therefore, the target network device 400b will know that

UE candidates

440a and 450a are to be offloaded to the target cell 400B, from the source cell 400A.

As

UE candidates

440a and 450a are to be offloaded to the target cell 400B, common beam weights for the source cell 400A is generated based on remaining

UEs

410a, 420a, 430a and 460a, excluding

UE candidates

440a and 450a.

A common beam for the source cell 400A can be formed based on the generated common beam weights for the source cell 400A. As shown in Fig. 4B, after common beam change, UEs 410a, 420a, 430a and 460a are covered by the first area 400A_1 with high common beam signal strength, and there is no UE covered by the second area 400A_2 with relatively lower common beam signal strength.

Refer back to Fig. 4A. A target network device 400b is associated with a target cell 400B. A plurality of terminal devices, such as

UEs

410b and 420b, are currently served by the target cell 400B. The target cell 400B comprises a first area 400B_1 with high common beam signal strength, and a second area 400B_2 with relatively lower common beam signal strength. UE 410b is covered by the first area 400B_1, while UE 420b is covered by the second area 400B_2.

From the source network device 400a associated with the source cell 400A, information of

UE candidates

440a and 450a are received.

UE candidates

440a and 450a are being served by the source cell 400A, but are to be offloaded to the target cell 400B.

After information of

UE candidates

440a and 450a to be offloaded to the target cell 400B are received, common beam weights for the target cell 400B is generated, based on

UEs

410b and 420b currently served by the target cell 400B as well as

UE candidates

440a and 450a to be offloaded to the target cell 400B.

A common beam for the target cell 400B can be formed based on the generated common beam weights for the target cell 400B. As shown in Fig. 4B, after common beam change,

UEs

410b, 420b, 440a and 450a are covered by the first area 400B_1 with high common beam signal strength, and there is no UE covered by the second area 400B_2 with relatively lower common beam signal strength.

A UE can detect a cell with high common beam signal strength, and send an access request (such as random-access request) to a network device associated with the cell accordingly. Therefore, as shown in Fig. 4B, after common beam changes of the source cell 400A and the target cell 400B, each of

UE candidates

440a and 450a can send an access request to the target network device 400b associated with the target cell 400B, due to coverage of the first area 400B_1 of the target cell 400B for these UEs. The target network device 400b can receive the access requests from

UE candidates

440a and 450a and respond accordingly, so that it can take over

UE candidates

440a and 450a.

As shown in Figs. 4A and 4B, it is possible to share the load of the overloaded source cell 400A by the target cell 400B with a relatively lower load, and adjust common beamforming accordingly, which enables cell-loading balance to be improved and efficient cell-coverage to be provided.

Fig. 5 is a block diagram of a source network device 500 associated with a source cell according to embodiments of the present disclosure, which can be, e.g., the source network device as described in connection with Fig. 2.

The source network device 500 comprises a processor 510 and a memory 520. Optionally, the source network device 500 may further comprise a transceiver 540 coupled to the processor 510. The memory 520 contains instructions 530 executable by the processor 510 to cause the source network device 500 to perform the actions of the method 200. Particularly, the memory 520 may contain instructions that, when executed by the processor 510, cause the source network device 500 to: select, from a plurality of terminal devices served by the source cell, at least one terminal device candidate to be offloaded, based at least on a load of the source cell; determine a target network device associated with a target cell being capable of taking over the at least one terminal device candidate; inform the target network device of the at least one terminal device candidate; and, generate common beam weights for the source cell, based on one or more remaining terminal devices in the plurality of terminal devices, with consideration that the selected at least one terminal device candidate is to be offloaded.

According to an embodiment, the memory 520 may further contain instructions that, when executed by the processor 510, cause the source network device 500 to assign the at least one terminal device candidate with a priority for generating common beam weights for the target cell, prior to informing the target network device of the at least one terminal device candidate, and informing the target network device of the at least one terminal device candidate can comprise informing the target network device of the assigned priority of the at least one terminal device candidate.

According to an embodiment, generating the common beam weights for the source cell can comprise assigning each of the one or more remaining terminal devices with a priority for generating the common beam weights for the source cell.

According to an embodiment, the source network device 500 associated with the source cell is configurable for controlling a MIMO antenna system, and the memory 520 may further contain instructions that, when executed by the processor 510, cause the source network device 500 to control the MIMO antenna system to form a common beam for the source cell, based on the generated common beam weights.

It should be noted that, more details described with reference to Figs. 2, 4A and 4B also apply here and may be omitted.

The memory 520 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory terminal devices, magnetic memory terminal devices and systems, optical memory terminal devices and systems, fixed memory and removable memory, as non-limiting examples.

The processor 510 may be of any type suitable to the local technical environment, and may comprise one or more of general purpose processors, special purpose processors (e.g., Application Specific Integrated Circuit (ASICs) ) , microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples.

Fig. 6 is a block diagram of an apparatus 600 according to embodiments of the present disclosure, which can be configured to perform the method 200 as described in connection with Fig. 2.

The apparatus 600 may comprise a selecting unit 610, a determining unit 620, an informing unit 630 and a generating unit 640. The selecting unit 610 may be configured to select, from a plurality of terminal devices served by the source cell, at least one terminal device candidate to be offloaded, based at least on a load of the source cell. The determining unit 620 may be configured to determine a target network device associated with a target cell being capable of taking over the at least one terminal device candidate. The informing unit 630 may be configured to inform the target network device of the at least one terminal device candidate. The generating unit 640 may be configured to generate common beam weights for the source cell, based on one or more remaining terminal devices in the plurality of terminal devices, with consideration that the selected at least one terminal device candidate is to be offloaded.

The apparatus 600 can be implemented as the source network device 500 or as a software and/or a physical device within the source network device 500 or communicatively coupled to the source network device 500.

Further details about the apparatus 600 are similar to those described with respect to Figs. 2, 4A and 4B, and are omitted here.

The units as described in Fig. 6 may be implemented as software and/or hardware, or a device comprising the software and/or the hardware, which is not limited. For example, they can be implemented as computer readable programs that can be executed by a processor. Alternatively, they can be implemented as processing circuitry such as ASICs and/or field programmable gate arrays (FPGAs) .

The present disclosure may also provide computer readable media having instructions thereon. The instructions, when executed by a processor of a source network device or a terminal device, cause the source network device or terminal device to perform the method according to the embodiments as described above. The computer readable media may include computer-readable storage media, for example, magnetic disks, magnetic tape, optical disks, phase change memory, or an electronic memory terminal device like a random access memory (RAM) , read only memory (ROM) , flash memory devices, CD-ROM, DVD, Blue-ray disc and the like. The computer readable media may also include computer readable transmission media (also called a carrier) , for example, electrical, optical, radio, acoustical or other form of propagated signals-such as carrier waves, infrared signals, and the like.

The present disclosure may also provide computer program products including instructions. The instructions, when executed by a processor of a source network device or a terminal device, cause the source network device or terminal device to perform the method according to the embodiments as described above.

Fig. 7 is a block diagram of a target network device 700 associated with a target cell according to embodiments of the present disclosure, which can be, e.g., the target network device as described in connection with Fig. 3.

The target network device 700 comprises a processor 710 and a memory 720. Optionally, the target network device 700 may further comprise a transceiver 740 coupled to the processor 710. The memory 720 contains instructions 730 executable by the processor 710 to cause the target network device 700 to perform the actions of the method 300. Particularly, the memory 720 may contain instructions that, when executed by the processor 710, cause the target network device 700 to: receive, from a source network device associated with a source cell, information of at least one terminal device candidate that is being served by the source cell and is to be offloaded to the target cell; and, generate common beam weights for the target cell, based on one or more terminal devices currently served by the target cell, as well as the at least one terminal device candidate to be offloaded to the target cell.

According to an embodiment, the memory 720 may further contain instructions that, when executed by the processor 710, cause the target network device 700 to assign the at least one terminal device candidate to be offloaded to the target cell with a first priority for generating the common beam weights for the target cell, prior to generating the common beam weights for the target cell.

According to an embodiment, the memory 720 may further contain instructions that, when executed by the processor 710, cause the target network device 700 to assign each of the one or more terminal devices currently served by the target cell with a second priority for generating the common beam weights for the target cell, prior to generating the common beam weights for the target cell.

According to an embodiment, the target network device 700 associated with the target cell is configurable for controlling a MIMO antenna system, and the memory 720 may further contain instructions that, when executed by the processor 710, cause the target network device 700 to controlling the MIMO antenna system to form a common beam for the target cell, based on the generated common beam weights.

It should be noted that, more details described with reference to Figs. 3, 4A and 4B also apply here and may be omitted.

The memory 720 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory terminal devices, magnetic memory terminal devices and systems, optical memory terminal devices and systems, fixed memory and removable memory, as non-limiting examples.

The processor 710 may be of any type suitable to the local technical environment, and may comprise one or more of general purpose processors, special purpose processors (e.g., Application Specific Integrated Circuit (ASICs) ) , microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples.

Fig. 8 is a block diagram of an apparatus 800 according to embodiments of the present disclosure, which can be configured to perform the method 300 as described in connection with Fig. 3.

The apparatus 800 may comprise a receiving unit 810 and a generating unit 820. The receiving unit 810 may be configured to receive, from a source network device associated with a source cell, information of at least one terminal device candidate that is being served by the source cell and is to be offloaded to the target cell. The generating unit 820 may be configured to generate common beam weights for the target cell, based on one or more terminal devices currently served by the target cell, as well as the at least one terminal device candidate to be offloaded to the target cell.

The apparatus 800 can be implemented as the target network device 700 or as a software and/or a physical device within the target network device 700 or communicatively coupled to the target network device 700.

Further details about the apparatus 800 are similar to those described with respect to Figs. 3, 4A and 4B, and are omitted here.

The units as described in Fig. 8 may be implemented as software and/or hardware, or a device comprising the software and/or the hardware, which is not limited. For example, they can be implemented as computer readable programs that can be executed by a processor. Alternatively, they can be implemented as processing circuitry such as ASICs and/or field programmable gate arrays (FPGAs) .

The present disclosure may also provide computer readable media having instructions thereon. The instructions, when executed by a processor of a target network device or a terminal device, cause the target network device or terminal device to perform the method according to the embodiments as described above. The computer readable media may include computer-readable storage media, for example, magnetic disks, magnetic tape, optical disks, phase change memory, or an electronic memory terminal device like a random access memory (RAM) , read only memory (ROM) , flash memory devices, CD-ROM, DVD, Blue-ray disc and the like. The computer readable media may also include computer readable transmission media (also called a carrier) , for example, electrical, optical, radio, acoustical or other form of propagated signals-such as carrier waves, infrared signals, and the like.

The present disclosure may also provide computer program products including instructions. The instructions, when executed by a processor of a target network device or a terminal device, cause the target network device or terminal device to perform the method according to the embodiments as described above.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representation, it will be appreciated that the blocks, units, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

With reference to Fig. 9, in accordance with an embodiment, a communication system includes a telecommunication network 910, such as a 3GPP-type cellular network, which comprises an access network 911, such as a radio access network, and a core network 914. The access network 911 comprises a plurality of

base stations

912a, 912b, 912c, such as NBs, eNBs, gNBs or other types of wireless access points, each defining a

corresponding coverage area

913a, 913b, 913c. Each

base station

912a, 912b, 912c is connectable to the core network 914 over a wired or wireless connection 915. A first user equipment (UE) 991 located in coverage area 913c is connectable to wirelessly connect to, or be paged by, the corresponding base station 912c. A second UE 992 in coverage area 913a is wirelessly connectable to the corresponding base station 912a. While a plurality of

UEs

991, 992 are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole UE is in the coverage area or where a sole UE is connecting to the corresponding base station 912.

The telecommunication network 910 is itself connected to a host computer 930, which may be embodied in the hardware and/or software of a standalone server, a cloud-implemented server, a distributed server or as processing retargets in a server farm. The host computer 930 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The

connections

921, 922 between the telecommunication network 910 and the host computer 930 may extend directly from the core network 914 to the host computer 930 or may go via an optional intermediate network 920. The intermediate network 920 may be one of, or a combination of more than one of, a public, private or hosted network; the intermediate network 920, if any, may be a backbone network or the Internet; in particular, the intermediate network 920 may comprise two or more sub-networks (not shown) .

The communication system of Fig. 9 as a whole enables connectivity between one of the connected

UEs

991, 992 and the host computer 930. The connectivity may be described as an over-the-top (OTT) connection 950. The host computer 930 and the connected

UEs

991, 992 are configured to communicate data and/or signaling via the OTT connection 950, using the access network 911, the core network 914, any intermediate network 920 and possible further infrastructure (not shown) as intermediaries. The OTT connection 950 may be transparent in the sense that the participating communication devices through which the OTT connection 950 passes are unaware of routing of uplink and downlink communications. For example, a base station 912 may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 930 to be forwarded (e.g., handed over) to a connected UE 991. Similarly, the base station 912 need not be aware of the future routing of an outgoing uplink communication originating from the UE 991 towards the host computer 930.

Example implementations, in accordance with an embodiment, of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to Fig. 10. In a communication system 1000, a host computer 1010 comprises hardware 1015 including a communication interface 1016 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 1000. The host computer 1010 further comprises processing circuitry 1018, which may have storage and/or processing capabilities. In particular, the processing circuitry 1018 may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The host computer 1010 further comprises software 1011, which is stored in or accessible by the host computer 1010 and executable by the processing circuitry 1018. The software 1011 includes a host application 1012. The host application 1012 may be operable to provide a service to a remote user, such as a UE 1030 connecting via an OTT connection 1050 terminating at the UE 1030 and the host computer 1010. In providing the service to the remote user, the host application 1012 may provide user data which is transmitted using the OTT connection 1050.

The communication system 1000 further includes a base station 1020 provided in a telecommunication system and comprising hardware 1025 enabling it to communicate with the host computer 1010 and with the UE 1030. The hardware 1025 may include a communication interface 1026 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 1000, as well as a radio interface 1027 for setting up and maintaining at least a wireless connection 1070 with a UE 1030 located in a coverage area (not shown in Fig. 10) served by the base station 1020. The communication interface 1026 may be configured to facilitate a connection 1060 to the host computer 1010. The connection 1060 may be direct or it may pass through a core network (not shown in Fig. 10) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system. In the embodiment shown, the hardware 1025 of the base station 1020 further includes processing circuitry 1028, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The base station 1020 further has software 1021 stored internally or accessible via an external connection.

The communication system 1000 further includes the UE 1030 already referred to. Its hardware 1035 may include a radio interface 1037 configured to set up and maintain a wireless connection 1070 with a base station target a coverage area in which the UE 1030 is currently located. The hardware 1035 of the UE 1030 further includes processing circuitry 1038, which may comprise one or more programmable processors, application-specific integrated circuits, field programmable gate arrays or combinations of these (not shown) adapted to execute instructions. The UE 1030 further comprises software 1031, which is stored in or accessible by the UE 1030 and executable by the processing circuitry 1038. The software 1031 includes a client application 1032. The client application 1032 may be operable to provide a service to a human or non-human user via the UE 1030, with the support of the host computer 1010. In the host computer 1010, an executing host application 1012 may communicate with the executing client application 1032 via the OTT connection 1050 terminating at the UE 1030 and the host computer 1010. In providing the service to the user, the client application 1032 may receive request data from the host application 1012 and provide user data in response to the request data. The OTT connection 1050 may transfer both the request data and the user data. The client application 1032 may interact with the user to generate the user data that it provides.

It is noted that the host computer 1010, base station 1020 and UE 1030 illustrated in Fig. 10 may be identical to the host computer 930, one of the

base stations

912a, 912b, 912c and one of the

UEs

991, 992 of Fig. 9, respectively. This is to say, the inner workings of these entities may be as shown in Fig. 10 and independently, the surrounding network topology may be that of Fig. 9.

In Fig. 10, the OTT connection 1050 has been drawn abstractly to illustrate the communication between the host computer 1010 and the use equipment 1030 via the base station 1020, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the UE 1030 or from the service provider operating the host computer 1010, or both. While the OTT connection 1050 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network) .

The wireless connection 1070 between the UE 1030 and the base station 1020 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the UE 1030 using the OTT connection 1050, in which the wireless connection 1070 forms the last segment. More precisely, the teachings of these embodiments may improve cell-loading balance and provide efficient cell-coverage, and thereby provide benefits such as better responsiveness.

A measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1050 between the host computer 1010 and UE 1030, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 1050 may be implemented in the software 1011 of the host computer 1010 or in the software 1031 of the UE 1030, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 1050 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which

software

1011, 1031 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1050 may include message format, retransmission settings, preferred routing etc. ; the reconfiguring need not affect the base station 1020, and it may be unknown or imperceptible to the base station 1020. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling facilitating the host computer’s 1010 measurements of throughput, propagation times, latency and the like. The measurements may be implemented in that the

software

1011, 1031 causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 1050 while it monitors propagation times, errors etc.

Fig. 11 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figs. 9 and 10. For simplicity of the present disclosure, only drawing references to Fig. 11 will be included in this section. In a first step 1110 of the method, the host computer provides user data. In an optional substep 1111 of the first step 1110, the host computer provides the user data by executing a host application. In a second step 1120, the host computer initiates a transmission carrying the user data to the UE. In an optional third step 1130, the base station transmits to the UE the user data which was carried in the transmission that the host computer initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional fourth step 1140, the UE executes a client application associated with the host application executed by the host computer.

Fig. 12 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figs. 9 and 10. For simplicity of the present disclosure, only drawing references to Fig. 12 will be included in this section. In a first step 1210 of the method, the host computer provides user data. In an optional substep (not shown) the host computer provides the user data by executing a host application. In a second step 1220, the host computer initiates a transmission carrying the user data to the UE. The transmission may pass via the base station, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step 1230, the UE receives the user data carried in the transmission.

Fig. 13 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figs. 9 and 10. For simplicity of the present disclosure, only drawing references to Fig. 13 will be included in this section. In an optional first step 1310 of the method, the UE receives input data provided by the host computer. Additionally or alternatively, in an optional second step 1320, the UE provides user data. In an optional substep 1321 of the second step 1320, the UE provides the user data by executing a client application. In a further optional substep 1311 of the first step 1310, the UE executes a client application which provides the user data in reaction to the received input data provided by the host computer. In providing the user data, the executed client application may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the UE initiates, in an optional third substep 1330, transmission of the user data to the host computer. In a fourth step 1340 of the method, the host computer receives the user data transmitted from the UE, in accordance with the teachings of the embodiments described throughout this disclosure.

Fig. 14 is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. The communication system includes a host computer, a base station and a UE which may be those described with reference to Figs. 9 and 10. For simplicity of the present disclosure, only drawing references to Fig. 14 will be included in this section. In an optional first step 1410 of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the base station receives user data from the UE. In an optional second step 1420, the base station initiates transmission of the received user data to the host computer. In a third step 1430, the host computer receives the user data carried in the transmission initiated by the base station.

The disclosure has been described above with reference to embodiments thereof. It should be understood that various modifications, alternations and additions can be made by those skilled in the art without departing from the spirits and scope of the disclosure. Therefore, the scope of the disclosure is not limited to the above particular embodiments but only defined by the claims as attached.

Claims

A method (200) at a source network device associated with a source cell, the method comprising:

selecting (210) , from a plurality of terminal devices served by the source cell, at least one terminal device candidate to be offloaded, based at least on a load of the source cell;

determining (220) a target network device associated with a target cell being capable of taking over the at least one terminal device candidate;

informing (230) the target network device of the at least one terminal device candidate; and

generating (240) common beam weights for the source cell, based on one or more remaining terminal devices in the plurality of terminal devices, with consideration that the selected at least one terminal device candidate is to be offloaded.
The method (200) of claim 1, further comprising: assigning the at least one terminal device candidate with a priority for generating common beam weights for the target cell, prior to informing the target network device of the at least one terminal device candidate,

wherein informing (230) the target network device of the at least one terminal device candidate comprises: informing the target network device of the assigned priority of the at least one terminal device candidate.
The method (200) of claim 1 or 2, wherein generating (240) the common beam weights for the source cell comprises: assigning each of the one or more remaining terminal devices with a priority for generating the common beam weights for the source cell.
The method (200) of claim 3, wherein generating (240) the common beam weights for the source cell further comprises:

acquiring channel information between each of the one or more remaining terminal devices and the source network device; and

generating the common beam weights for the source cell, based on the channel information and the assigned priority of each of the one or more remaining terminal devices.
The method (200) of any one of claims 1-4, wherein the source network device associated with the source cell is configurable for controlling a multiple input multiple output (MIMO) antenna system, and

wherein the method (200) further comprises: controlling the MIMO antenna system to form a common beam for the source cell, based on the generated common beam weights.
A method (300) at a target network device associated with a target cell, the method comprising:

receiving (310) , from a source network device associated with a source cell, information of at least one terminal device candidate that is being served by the source cell and is to be offloaded to the target cell; and

generating (320) common beam weights for the target cell, based on one or more terminal devices currently served by the target cell, as well as the at least one terminal device candidate to be offloaded to the target cell.
The method (300) of claim 6, wherein the information of the at least one terminal device candidate to be offloaded to the target cell comprises an assigned first priority for generating the common beam weights for the target cell of the at least one terminal device candidate.
The method (300) of claim 6, further comprising: assigning the at least one terminal device candidate to be offloaded to the target cell with a first priority for generating the common beam weights for the target cell, prior to generating the common beam weights for the target cell.
The method (300) of claim 7 or 8, further comprising: assigning each of the one or more terminal devices currently served by the target cell with a second priority for generating the common beam weights for the target cell, prior to generating the common beam weights for the target cell.
The method (300) of claim 9, wherein generating (320) the common beam weights for the target cell comprises:

acquiring first channel information between the at least one terminal device candidate and the target network device, and second channel information between each of the one or more terminal devices currently served by the target cell and the target network device; and

generating the common beam weights for the target cell, based on the first and the second channel information, the first priority of the at least one terminal device candidate, and the second priority of each of the one or more terminal devices currently served by the target cell.
The method (300) of any one of claims 6-10, wherein the target network device associated with the target cell is configurable for controlling a multiple input multiple output (MIMO) antenna system, and

wherein the method (300) further comprises: controlling the MIMO antenna system to form a common beam for the target cell, based on the generated common beam weights.
A source network device (700) associated with a source cell, comprising:

a processor (710) ;

a memory (720) configured to store instructions (730) , wherein the instructions (730) , when executed by the processor (710) , cause the source network device (700) to:

select, from a plurality of terminal devices served by the source cell, at least one terminal device candidate to be offloaded, based at least on a load of the source cell;

determine a target network device associated with a target cell being capable of taking over the at least one terminal device candidate;

inform the target network device of the at least one terminal device candidate; and

generate common beam weights for the source cell, based on one or more remaining terminal devices in the plurality of terminal devices, with consideration that the selected at least one terminal device candidate is to be offloaded.
The source network device (700) of claim 12, wherein the memory (720) is further configured to store instructions (730) that, when executed by the processor (710) , cause the source network device (700) to perform the method (200) according to any one of claims 2-5.
A computer-readable storage medium having instructions stored thereon, wherein the instructions, when executed by a processor of a source network device associated with a source cell, cause the source network device to perform the method according to any one of claims 1-5.
A computer program product comprising instructions, wherein the instructions, when executed by a processor of a source network device associated with a source cell, cause the source network device to perform the method according to any one of claims 1-5.
A target network device (600) associated with a target cell, comprising:

a processor (610) ;

a memory (620) configured to store instructions (730) , wherein the instructions (730) , when executed by the processor (610) , cause the target network device (600) to:

receive, from a source network device associated with a source cell, information of at least one terminal device candidate that is being served by the source cell and is to be offloaded to the target cell; and

generate common beam weights for the target cell, based on one or more terminal devices currently served by the target cell, as well as the at least one terminal device candidate to be offloaded to the target cell.
The target network device (600) of claim 16, wherein the memory (620) is further configured to store instructions (730) that, when executed by the processor (610) , cause the target network device (600) to perform the method (300) according to any one of claims 7-11.
A computer-readable storage medium having instructions stored thereon, wherein the instructions, when executed by a processor of a target network device associated with a target cell, cause the target network device to perform the method according to any one of claims 6-11.
A computer program product comprising instructions, wherein the instructions, when executed by a processor of a target network device associated with a target cell, cause the target network device to perform the method according to any one of claims 6-11.