WO2017197642A1

WO2017197642A1 - Dynamic csi-rs sharing scheme

Info

Publication number: WO2017197642A1
Application number: PCT/CN2016/082814
Authority: WO
Inventors: Deshan Miao; Yi Zhang
Original assignee: Nokia Technologies Oy
Priority date: 2016-05-20
Filing date: 2016-05-20
Publication date: 2017-11-23
Also published as: EP3459304A1; EP3459304A4

Abstract

A method is provided including dividing communication resources into a plurality of resource pools for transmission of at least one reference signal; determining a user specific measurement pattern for each of a plurality of user equipments; assigning the plurality of user equipments to one of the resource pools; and transmitting an indication of the assigned resource pool and the user specific measurement pattern to each of the plurality of user equipments to configure the plurality of user equipments to measure and report quality information using the communication resource within the assigned resource pool.

Description

DYNAMIC CSI-RS SHARING SCHEME

TECHNICAL FIELD

This invention relates generally to wireless communications and， more specifically， relates to channel state information measurement for wireless communications.

BACKGROUND

Since Long Term Evolution (LTE) Release 10 (R10) ， Channel State Information Reference Signal (CSI-RS) is used to measure DL channel information， and ZP-CSI-RS is used for DL interference measurement. In order to enable CQI measurement， CSI-RS and ZP-CSI-RS are often configured together. Typically， periodic CSI-RS is configured by default， and additionally， aperiodic CQI reporting is enabled to improve feedback accuracy. Also， UE specific CSI-RS resources are configured statically by eNB and assigned to a given UE. According to this fixed CSI-RS resource assignment each UE is only indicated with one UE specific CSI-RS resource within one CSI process， and one UE is configured with at most three CSI-RS processes. However， in 5G， the number of UEs will increase significantly， and therefore， static CSI-RS resource assignment will not be efficient.

BRIEF SUMMARY

The following summary is merely intended to be exemplary. The summary is not intended to limit the scope of the claims.

In accordance with one aspect， an example method comprises dividing communication resources into a plurality of resource pools for transmission of at least one reference signal； determining a user specific measurement pattern for each of a plurality of user equipments； assigning the plurality of user equipments to one of the resource pools； and transmitting an indication of the assigned resource pool and the user specific measurement pattern to each of the plurality of user equipments to configure the plurality of user equipments to measure and report quality information using the communication resource within the assigned resource pool.

In accordance with another aspect， an example embodiment is provided in an apparatus comprising at least one processor； and at least one non-transitory memory including computer program code， the at least one memory and the computer program code configured to， with the at least one processor， cause the apparatus to： divide communication resources into a plurality of resource pools for transmission of at least one reference signal； determine a user specific measurement pattern for each of a plurality of user equipments； assign the plurality of user equipments to one of the resource pools； and transmit an indication of the assigned resource pool and the user specific measurement pattern to each of the plurality of user equipments to configure the plurality of user equipments to measure and report quality information using the communication resource within the assigned resource pool.

In accordance with another aspect， an example method comprises： receiving， by a user equipment， measurement information comprising an indication of a resource pool corresponding to communication resources and a user specific measurement pattern for measuring at least one reference signal， wherein the communication resources are shared by a plurality of user equipments； measuring quality information based on the at least one reference signal according to the user specific measurement pattern； and transmitting， via the shared communication resources， a measurement report based at least on the measuring.

In accordance with another aspect， an example embodiment is provided in an apparatus comprising at least one processor； and at least one non-transitory memory including computer program code， the at least one memory and the computer program code configured to， with the at least one processor， cause the apparatus to： receive， by a user equipment， measurement information comprising an indication of a resource pool corresponding to communication resources and a user specific measurement pattern for measuring at least one reference signal， wherein the communication resources are shared by a plurality of user equipments； measure quality information based on the at least one reference signal according to the user specific measurement pattern； and transmit， via the shared communication resources， a measurement report based at least on the measuring

BRIEF DESCRIPTION OF THE DRAWINGS

In the attached Drawing Figures：

FIG. 1 is a block diagram of one possible and non-limiting exemplary system in which the exemplary embodiments may be practiced；

FIG. 2 illustrates an example common CSI-RS resource pool according exemplary embodiments；

FIG. 3 illustrates an example traffic pattern of a user equipment according to exemplary embodiments；

FIG. 4 illustrates an example periodic pattern based measurement configuration according to exemplary embodiments；

FIG. 5 illustrates an example one time window based measurement configuration according to exemplary embodiments；

FIGS. 6 and 7 are logic flow diagrams for dynamic CSI-RS sharing scheme， and illustrate the operation of an exemplary method， a result of execution of computer program instructions embodied on a computer readable memory， functions performed by logic implemented in hardware， and/or interconnected means for performing functions in accordance with exemplary embodiments.

DETAILED DESCRIPTION OF THE DRAWINGS

The word “exemplary” is used herein to mean “serving as an example， instance， or illustration. ” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described in this Detailed Description are exemplary embodiments provided to enable persons skilled in the art to make or use the invention and not to limit the scope of the invention which is defined by the claims.

The exemplary embodiments herein describe techniques for dynamic CSI-RS sharing scheme. Additional description of these techniques is presented after a system into which the exemplary embodiments may be used is described.

Turning to FIG. 1， this figure shows a block diagram of one possible and non-limiting exemplary system in which the exemplary embodiments may be practiced. In FIG. 1， a user equipment (UE) 110 is in wireless communication with a wireless network 100. A UE is a wireless， typically mobile device that can access a wireless network. The UE 110 includes one or more processors 120， one or more memories 125， and one or more transceivers 130 interconnected through one or more buses 127. Each of the one or more transceivers 130 includes a receiver， Rx， 132 and a transmitter， Tx， 133. The one or more buses 127 may be address， data， or control buses， and may include any interconnection mechanism， such as a series of lines on a motherboard or integrated circuit， fiber optics or other optical communication equipment， and the like. The one or more transceivers 130 are connected to one or more antennas 128. The one or more memories 125 include computer program code 123. The UE 110 includes a Measurement Module 140， comprising one of or both parts 140-1 and/or 140-2， which may be implemented in a number of ways. The Measurement Module 140 may be implemented in hardware as Measurement Module 140-1， such as being implemented as part of the one or more processors 120. The Measurement Module 140-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example， the Measurement Module 140 may be implemented as Measurement Module 140-2， which is implemented as computer program code 123 and is executed by the one or more processors 120. For instance， the one or more memories 125 and the computer program code 123 may be configured to， with the one or more processors 120， cause the user equipment 110 to perform one or more of the operations as described herein. The UE 110 communicates with eNB 170 via a wireless link 111.

The eNB (evolved NodeB) 170 is a base station (e.g.， for LTE， long term evolution) that provides access by wireless devices such as the UE 110 to the wireless network 100. The eNB 170 includes one or more processors 152， one or more memories 155， one or more network interfaces (N/W I/F (s) ) 161， and one or more transceivers 160 interconnected through one or more buses 157. Each of the one or more transceivers 160 includes a receiver， Rx， 162 and a transmitter， Tx， 163. The one or more transceivers 160 are connected to one or more antennas 158. The one or more memories 155 include computer program code 153. The eNB 170 includes a Configuration Module 150， comprising one of or both parts 150-1 and/or 150-2， which may be implemented in a number of ways. The Configuration Module 150 may be implemented in hardware as Configuration Module 150-1， such as being implemented as part of the one or more processors 152. The Configuration Module 150-1 may be implemented also as an integrated circuit or through other hardware such as a programmable gate array. In another example， the Configuration Module 150 may be implemented as Configuration Module 150-2， which is implemented as computer program code 153 and is executed by the one or more processors 152. For instance， the one or more memories 155 and the computer program code 153 are configured to， with the one or more processors 152， cause the eNB 170 to perform one or more of the operations as described herein. The one or more network interfaces 161 communicate over a network such as via the links 176 and 131. Two or more eNBs 170 communicate using， e.g.， link 176. The link 176 may be wired or wireless or both and may implement， e.g.， an X2 interface.

The one or more buses 157 may be address， data， or control buses， and may include any interconnection mechanism， such as a series of lines on a motherboard or integrated circuit， fiber optics or other optical communication equipment， wireless channels， and the like. For example， the one or more transceivers 160 may be implemented as a remote radio head (RRH) 195， with the other elements of the eNB 170 being physically in a different location from the RRH， and the one or more buses 157 could be implemented in part as fiber optic cable to connect the other elements of the eNB 170 to the RRH 195.

It is noted that description herein indicates that “cells” perform functions， but it should be clear that the eNB that forms the cell will perform the functions. The cell makes up part of an eNB. That is， there can be multiple cells per eNB. For instance， there could be three cells for a single eNB cartier frequency and associated bandwidth， each cell covering one-third of a 360 degree area so that the single eNB’s coverage area covers an approximate oval or circle. Furthermore， each cell can correspond to a single carrier and an eNB may use multiple carriers. So ifthere are three 120 degree cells per cartier and two carriers， then the eNB has a total of 6 cells.

The wireless network 100 may include a network control element (NCE) 190 that may include MME (Mobility Management Entity) /SGW (Serving Gateway) functionality， and which provides connectivity with a further network， such as a telephone network and/or a data communications network (e.g.， the Internet) . The eNB 170 is coupled via a link 131 to the NCE 190. The link 131 may be implemented as， e.g.， an S1 interface. The NCE 190 includes one or more processors 175， one or more memories 171， and one or more network interfaces (N/W I/F(s) ) 180， interconnected through one or more buses 185. The one or more memories 171 include computer program code 173. The one or more memories 171 and the computer program code 173 are configured to， with the one or more processors 175， cause the NCE 190 to perform one or more operations.

The wireless network 100 may implement network virtualization， which is the process of combining hardware and software network resources and network functionality into a single， software-based administrative entity， a virtual network. Network virtualization involves platform virtualization， often combined with resource virtualization. Network virtualization is categorized as either external， combining many networks， or parts of networks， into a virtual unit， or internal， providing network-like functionality to software containers on a single system. Note that the virtualized entities that result from the network virtualization are still implemented， at some level， using hardware such as

processors

152 or 175 and

memories

155 and 171， and also such virtualized entities create technical effects.

The computer

readable memories

125， 155， and 171 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 devices， flash memory， magnetic memory devices and systems， optical memory devices and systems， fixed memory and removable memory. The computer

readable memories

125， 155， and 171 may be means for performing storage functions. The

processors

120， 152， and 175 may be of any type suitable to the local technical environment， and may include one or more of general purpose computers， special purpose computers， microprocessors， digital signal processors (DSPs) and processors based on a multi-core processor architecture， as non-limiting examples. The

processors

120， 152， and 175 may be means for performing functions， such as controlling the UE 110， eNB 170， and other functions as described herein.

In general， the various embodiments of the user equipment 110 can include， but are not limited to， cellular telephones such as smart phones， tablets， personal digital assistants (PDAs) having wireless communication capabilities， portable computers having wireless communication capabilities， image capture devices such as digital cameras having wireless communication capabilities， gaming devices having wireless communication capabilities， music storage and playback appliances having wireless communication capabilities， Internet appliances permitting wireless Internet access and browsing， tablets with wireless communication capabilities， as well as portable units or terminals that incorporate combinations of such functions.

Having thus introduced one suitable but non-limiting technical context for the practice of the exemplary embodiments of this invention， the exemplary embodiments will now be described with greater specificity.

CSI-RS and ZP CSI-RS are crucial to UE CQI measurements. Conventionally， MIMO transmission， SU-MIMO， MU-MIMO， multi-site MIMO require different measurement hypotheses， where one hypothesis requires one unique CSI-RS/ZP-CSI-RS resource pair. For 5G networks， antenna structure is more complicated due to the increase in the number of antenna elements and the requirement for frequency band specific implementation. MIMO mode will be more diverse in this context. For example， transceiver unit (TXRU) ， antenna port， and antenna elements mapping will have more possible implementation， which will also require more CQI report hypotheses and more CSI-RS resources.

For time division duplexing (TDD) beamforming， different UEs will have different beamforming vectors based on channel reciprocity， and in theory， the network should configure different CSI-RS/ZP-CSI-RS resources for each of these UEs. In this case， CSI-RS and ZP-CSI-RS resource requiremen ts are increased by ten times or even more.

In LTE smart phone service， a UE will often transmit data with a certain burst pattern. The UE is not always transmitting data during the entire RRC connection period. For this case， periodic and fixed CSI-RS configurations result in inefficient CSI-RS utilization.

Massive MTC is an important issue for 5G wireless networks. Massive MTC allows a huge number of UEs within one cell to connect to the network. However， not all the UEs are actively transmitting data. Data traffic may be burst specific for massive MTC， for example， and therefore only a limited CQI measurement duration is needed.

Based on the issues above， the typical technique of directly assigning CSI-RS resources is ineffective since it will eat system offered capacity. According to embodiments described herein， techniques are provided for improving CSI-RS utilization efficiency by sharing the same CSI-RS resources between different UEs in a dynamic way and and by providing a corresponding CSI-RS measurement mechanism. These techniques will help improve CSI-RS resource utilization efficiency to meet the more demanding CQI measurement requirements.

In 3GPP TR 36.897， there is a proposal， in which a UE is configured with a CSI process on which the actual NZP CSI-RS transmission and CSI-IM measurement instances are controlled by eNB and signaled to the UE.

Embodiments herein provide a dynamic CSI-RS resource sharing scheme. According to an exemplary embodiment， the following steps， which are described in greater detail below， may be formed by， e.g.， a base station：

●Setting up CSI-RS and/or ZP-CSI-RS resource pools and inform them to UE. User equipments that are associated with a cell are informed of the resource pools. For the whole cell there may be multiple possible resource pools， and a user equipment in the cell may be notified of only one of the resource pools for CSI measurement. A given user equipment in the cell may be informed of a single resource pool having one or multiple copies of CSI-RS resources， where one CSI-RS resource refers to one resource elements group used to measure CSI of one or multiple antenna ports. One ZP-CSI-RS resource refers to one resource elements group that is used to measure the interference from a neighboring cell， a neighboring beam， or a neighboring transmission point. Although the term ‘resource pool’ is used herein， it should be understood that other terms may be used such as resource groups， clusters， sets， etc. Moreover， in order to assist rate matching， one or multiple resource pools can be indicated to UE.

●The base station formulates UE specific CSI-RS measurement patterns according to traffic characteristics of each UE， wherein each UE may have one or multiple CSI-RS measurement pattern to match different traffic characteristics.

●The base station coordinates multiple UEs to share a common CSI-RS/ZP-CSI-RS resource for monitoring and reporting the CSI-RS/ZP-CSI-RS resources.

●Inform UE to monitor/measure indicated CSI-RS/ZP-CSI-RS resource and report CQI according to indicated CSI-RS/NZP-CSI-RS measurement pattern. Indication could UE specific or group UE specific. In addition， this indication may comprise a rate matching pattern， which can help UE to do rate matching based on one or multiple resource pools. A rate matching pattern is used for a user equipment to determine which resource elements are reserved by CSI-RS or ZP-CSI-RS. Then the transmitted data packet will not be assigned in these resource elements. When UE is indicated with a rate matching pattern， the demodulation reliability can be improved.

In one embodiment， the base station may inform a user equipment to measure CSI-RS in particular time or frequency band of CSI-RS resource. In another embodiment， the base station may inform a user equipment to measure a new CSI-RS resource index within a resource pool that was previously indicated. In another embodiment， the base station may inform a user equipment about CSI-RS resource to beam mapping relationship or which beams are active to update CSI-RS resource measurement configuration. For this beamforming case， it is possible to define more beams than CSI-RS resources， and during one period， only partial beam specific CSI-RS may be measured， or one beam specific CSI-RS can be measured only in partial frequency resource of one CSI-RS resource. Herein one beam specific CSI-RS may comprise of one or multiple beamformed CSI-RS ports.

The steps above are now described in more detail with reference to the figures.

CSI-RS Resource Pool Configuration： The base station sets up CSI-RS and/or ZP-CSI-RS resource pools. One CSI-RS/ZP-CSI-RS resource pool is defined as one set of CSI-RS resource. One CSI-RS resource may comprise one or multiple CSI-RS/ZP-CSI-RS resource units. Each resource unit could be associated with a resource elements group and be indexed. This resource is specified as periodic time-frequency resource. Specially， there could be one whole subframe used for common CSI-RS and ZP-CSI-RS resource.

Referring to FIG. 2， this figure illustrates an example CSI-RS/ZP-CSI-RS resource pool. An example subframe 200 is defined on a time 202 and frequency 204 chart. The subframe 200 includes five subbands (labeled subbandl-suband5) . Multiple CSI-RS/ZP-CSI-RS resource units 210 are shown. These resource units 210 collectively form the CSI-RS resource pool as described above.

UE Traffic Pattern Extraction： Normally UE traffic pattern could be estimated and derived by a base station， based on a UE’s traffic pattern， and a CSI-RS measurement pattern may be determined for that UE. FIG. 3 illustrates an example traffic pattern for a smart phone in relation to time. In FIG. 3， the different shaded bars indicate the traffic of different services and applications of the smart phone. For example， the traffic indicated by bar 302 may be for a weather application， the traffic indicated by bar 304 may be location services， and the traffic indicated by bar 306 instant messaging. The base station may extracts the UE traffic pattern according to the traffic patterns. For example， the traffic patterns relating to bar 302 and bar 304 are regular and may easily be estimated. For these cases， since the UE is only active in certain time window， one regular CSI-RS measurement pattern may be configured by the base station. However， in some situations the traffic pattern is not regular， or different traffics are mixed together. In these situations， when a regular traffic pattern is hard to estimate for base station， a one-time window could be set up. This means the UE will measure CSI-RS/ZP-CSI-RS resource within one shot time window. For each triggering/activation， only one time window for CSI-RS measurement is effective. The UE will stop the measurement after it expires unless receiving new activation command. In order to match different traffic characteristic， one UE may have multiple CSI-RS measurement patterns.

Multiple UE coordination to share common CSI-RS resource： Ifmultiple UEs have different CSI-RS measurement pattern due to traffic differences， then the base station may still arrange multiple UEs to share one single CSI-RS resource. In these situations the base station may assign， for example， different CSI-RS measurement patterns to different UEs and coordinate these UEs to use the same one single CSI-RS resource. This significantly improves CSI-RS utilization efficiency.

CSI-RS measurement pattern configuration： According to embodiments herein， the base station sets up one pattern according to UE DL service characteristic， and the UE is notified to measure CSI-RS/ZP-CSI-RS based on a specific pattern. This specific pattern could be one of pre-configured patterns. The CSI-RS transmission period is independent of the CSI-RS measurement pattern.

Referring to FIG. 4 and FIG. 5， these figures provide non-limiting examples of CSI-RS measurement configurations. FIG. 4 illustrates an example CSI-RS measurement configuration for a UE 400. This measurement configuration include an “ON” period 402， where the UE will measure CSI-RS， derive CQI， and report it to the base station. During the “OFF” period 404， the CSI-RS could be used by a different UE， and no CQI report is needed. In some embodiments this ON-OFF pattern may be aligned with UE DRX pattern. From the CSI-RS type point of view， it similar to one semi-persistent scheduled CSI-RS transmission.

FIG. 5 provides an example CSI-RS measurement configuration for a UE1 500 having a single one-time window configuration. In this example， the one-time window 502 is the only opportunity for the UE1 500 to measure the CSI-RS， derive CQI， and report it to the base station. The remaining portion of the pattern 504， may be used for the base station to schedule a different UE.

It should be understood that these measurement patterns from FIG. 4 and FIG. 5 may be used in conjunction by the base station to schedule different user equipments to the same resource pool RS/ZP-CSI-RS resource pool. The example measurement patterns described above are only example， and other patterns may be used. For example， the CSI-RS measurement pattern may be periodic or aperiodic depending on the base station determination and configuration. In another example， one measurement pattern may be the default measurement pattern so that no configuration is needed by the base station.

Signalling Indication： The signalling from the base station to the user equipment of the measurement pattern may be done in two ways： a semi-static RRC command； and a dynamic MAC or a physical DL control command.

For the RRC signalling， the signalled information may comprise an indication of the common resource pool. The indication may include at least one of： a CSI-RS/ZP CSI-RS resource location， a resource index， a measured antenna port， a time period， etc. Additionally， this indication would indicate one UE specific CSI-RS/ZP-CSI-RS pattern to the UE. If the pattern is a one-time window (as described above with reference to FIG. 5) an alternative indication using dynamic signalling to activate and stop CSI-RS measurement may be used. The indication of the measurement pattern is UE specific， whereas the common resource pool may be specific to a cell or a group UEs. One UE may have one or multiple CSI-RS measurement patterns for RRC configuration.

For dynamic signaling， the indication may be sent via a MAC command or downlink physical control indicator to inform UE. Dynamic signaling comprises limited information bits， used to fast trigger UE to measure CSI-RS/ZP-CSI-RS and report CQI. Dynamic signaling may also be used to indicate one of multiple CSI-RS measurement pattern. The signaling may be UE specific or group UE specific. This means dynamic sharing may be allowed witthin one group of UEs or among multiple groups of UEs.

For signaling indication， RRC signaling and dynamic signaling may be combined or only RRC signaling may be used. In a certain case， only RRC signaling is enough to support multiple users to share same CSI-RS resource， and there is no need to change CSI-RS resource index or CSI-RS measurement pattern. For example， two users may be configured to have ON-OFF inter-locked measurement pattern to share same CSI-RS/ZP-CSI-RS resource.

FIG. 6 is a logic flow diagram for a dynamic CSI-RS sharing scheme. This figure further illustrates the operation of an exemplary method， a result of execution of computer program instructions embodied on a computer readable memory， functions performed by logic implemented in hardware， and/or interconnected means for performing functions in accordance with exemplary embodiments. For instance， the Measurement Module 140 may include multiples ones of the blocks in FIG. 6， where each included block is an interconnected means for performing the function in the block. The blocks in FIG. 6 are assumed to be performed by the UE 110， e.g.， under control of the Measurement Module 140 at least in part.

Referring to FIG. 6， an example method may comprise： receiving， by a user equipment， measurement information comprising an indication of a resource pool corresponding to communication resources and a user specific measurement pattern for measuring at least one reference signal， wherein the communication resources are shared by a plurality of user equipments as indicated by block 602； measuring quality information based on the at least one reference signal according to the user specific measurement pattern as indicated by block 604； and transmitting， via the shared communication resources， a measurement report based at least on the measuring as indicated by block 606.

The at least one reference signal may be at least one of： a channel state information reference signal (CSI-RS) for measurement of channel information； and a zero-power channel state information reference signal (ZP-CSI-RS) for measurement of interference information. The indication of the assigned resource pool may be received via radio resource control (RRC) signaling， and wherein the indication comprises at least one of： an allocation of the communication resource corresponding to the assigned resource pool； a resource index； at least one antenna port to be measured； and a time period. The method may further comprise： receiving a rate matching pattern information comprising one or more resource pools， and performing rate matching according to the indicated rate matching pattern. The communication resources may be shared by the plurality of user equipments using at least one of： time division multiplexing (TDM) and frequency division multiplexing (FDM) . The user specific measurement pattern may be at least one of： a periodic CSI measurement pattern； a one-time window measurement pattern； a CSI measurement pattern including a fractional time resource of one periodic CSI-RS resource； a CSI measurement pattern including a fractional frequency resource of one periodic CSI-RS resource. The user specific measurement pattern may be received via at least one of： radio resource control signaling， media access control signaling and physical layer signaling.

An example apparatus may be provided comprising at least one processor； and at least one non-transitory memory including computer program code， the at least one memory and the computer program code may be configured to， with the at least one processor， cause the apparatus to： receive， by a user equipment， measurement information comprising an indication of a resource pool corresponding to communication resources and a user specific measurement pattern for measuring at least one reference signal， wherein the communication resources are shared by a plurality of user equipments； measure quality of the at least one reference signal according to the user specific measurement pattern； and transmit， via the shared communication resources， a measurement report based at least on the measuring.

The at least one reference signal may be at least one of： a channel state information reference signal (CSI-RS) for measurement of channel state information； and a zero-power channel state information reference signal (ZP-CSI-RS) for measurement of interference information. The indication of the assigned resource pool is received via radio resource control (RRC) signaling， and wherein the indication may comprise at least one of： an allocation of the communication resource corresponding to the assigned resource pool； a resource index； at least one antenna port to be measured； and a time period. The at least one memory and the computer program code may be configured to， with the at least one processor， cause the apparatus to： receive a rate matching pattern information comprising one or more resource pools， and perform rate matching according to the indicated rate matching pattern. The user specific measurement pattern may be at least one of： a periodic CSI measurement pattern； a one-time window measurement pattern； a CSI measurement pattern including a fractional time resource of one periodic CSI-RS resource； a CSI measurement pattern including a fractional frequency resource of one periodic CSI-RS resource.

An example embodiment may be provided in a non-transitory program storage device， such as memory (ies) 125 shown in Fig. 1 for example， readable by a machine， tangibly embodying a program of instructions executable by the machine for performing operations， the operations comprising： receiving， by a user equipment， measurement information comprising an indication of a resource pool corresponding to communication resources and a user specific measurement pattern for measuring at least one reference signal， wherein the communication resources are shared by a plurality of user equipments； measuring quality information based on the at least one reference signal according to the user specific measurement pattern； and transmitting， via the shared communication resources， a measurement report based at least on the measuring.

FIG. 7 is a logic flow diagram for a dynamic CSI-RS sharing scheme. This figure further illustrates the operation of an exemplary method， a result of execution of computer program instructions embodied on a computer readable memory， functions performed by logic implemented in hardware， and/or interconnected means for performing functions in accordance with exemplary embodiments. For instance， the Configuration Module 150 may include multiples ones of the blocks in FIG. 7， where each included block is an interconnected means for performing the function in the block. The blocks in FIG. 7 are assumed to be performed by a base station such as eNB 170， e.g.， under control of the Configuration Module 150 at least in part.

Referring to FIG. 7， an example method may comprise dividing communication resources into a plurality of resource pools for transmission of at least one reference signal as indicated by block 702； determining a user specific measurement pattern for each of a plurality of user equipments as indicated by block 704； assigning the plurality of user equipments to one of the resource pools as indicated by block 706； and transmitting an indication of the assigned resource pool and the user specific measurement pattern to each of the plurality of user equipments to configure the plurality of user equipments to measure and report quality information using the communication resource within the assigned resource pool as indicated by block 708.

The at least one reference signal may be at least one of： a channel state information reference signal (CSI-RS) for measurement of channel information； and a zero-power channel state information reference signal (ZP-CSI-RS) for measurement of interference information. The different user specific measurement patterns may be determined based on whether the at least one reference signal is a CSI-RS or a ZP-CSI-RS. The user specific measurement pattern may be based at least on traffic characteristics of the respective user equipments. The determining may further comprise determining a different user specific measurement pattern for a first user equipment of the plurality of user equipments and a second user equipment of the plurality of user equipments based on different traffic characteristics of the first user equipment and the second user equipment. The plurality of user equipments may share the communication resources corresponding to the assigned resource pool using at least one of： time division multiplexing (TDM) and frequency division multiplexing (FDM) . The indication of the assigned resource pool may be transmitted via radio resource control (RRC) signaling， and the indication may comprise at least one of： an allocation of the communication resource corresponding to the assigned resource pool； a resource index； at least one antenna port to be measured； and a time period. The user specific measurement pattern may be at least one of： a periodic CSI measurement pattern， a one-time window measurement pattern； a fractional time， and a frequency resource to measure within one periodic CSI-RS resource. The user specific measurement pattern may be transmitted via at least one of： radio resource control signaling， media access control signaling and physical layer signaling. The method may further comprise transmitting an indication of a rate matching pattern， wherein the rate matching pattern may comprise one or multiple resource pools. The method may further comprise： transmitting the at least one reference signal； and receiving a measurement report based on the assigned resource pool and the user specific measurement pattern comprising the quality information from at least one user equipment.

An example apparatus may be provided comprising at least one processor； and at least one non-transitory memory including computer program code， the at least one memory and the computer program code may be configured to， with the at least one processor， cause the apparatus to： divide communication resources into a plurality of resource pools for transmission of at least one reference signal； determine a user specific measurement pattern for each of a plurality of user equipments； assign the plurality of user equipments to one of the resource pools； and transmit an indication of the assigned resource pool and the user specific measurement pattern to each of the plurality of user equipments to configure the plurality of user equipments to measure and report quality information using the communication resource within the assigned resource pool.

The at least one reference signal may be at least one of： a channel state information reference signal (CSI-RS) for measurement of channel information； and a zero-power channel state information reference signal (ZP-CSI-RS) for measurement of interference information. The different user specific measurement patterns may be determined based on whether the at least one reference signal is a CSI-RS or a ZP-CSI-RS. The user specific measurement pattern may be based at least on traffic characteristics of the respective user equipments. The determination of the user specific measurement pattern for each of a plurality of user equipments may comprise determining a different user specific measurement pattern for a first user equipment of the plurality of user equipments and a second user equipment of the plurality of user equipments based on different traffic characteristics of the first user equipment and the second user equipment. The indication of the assigned resource pool may be transmitted via radio resource control (RRC) signaling， and wherein the indication may comprise at least one of：an allocation of the communication resource corresponding to the assigned resource pool； a resource index； at least one antenna port to be measured； and a time period. The user specific measurement pattern may be at least one of： a periodic CSI measurement pattern， a one-time window measurement pattern； a fractional time， and a frequency resource to measure within one periodic CSI-RS resource. The user specific measurement pattern may be transmitted via at least one of： radio resource control signaling， media access control signaling and physical layer signaling. The at least one memory and the computer program code configured to， with the at least one processor， cause the apparatus to： transmit an indication of a rate matching pattern， wherein the rate matching pattern comprises one or multiple resource pools.

An example embodiment may be provided in a non-transitory program storage device， such as memory (ies) 155 shown in Fig. 1 for example， readable by a machine， tangibly embodying a program of instructions executable by the machine for performing operations， the operations comprising： dividing communication resources into a plurality of resource pools for transmission of at least one reference signal； determining a user specific measurement pattern for each of a plurality of user equipments； assigning the plurality of user equipments to one of the resource pools； and transmitting an indication of the assigned resource pool and the user specific measurement pattern to each of the plurality of user equipments to configure the plurality of user equipments to measure and report quality information using the communication resource within the assigned resource pool.

An example embodiment may be provided in a communication system including an apparatus in accordance with paragraph 0050 and an apparatus in accordance with paragraph 0056 above， for example.

Without in any way limiting the scope， interpretation， or application of the claims appearing below， a technical effect of one or more of the example embodiments disclosed herein is that different UEs will share one common resource pool thus increasing CSI-RS utilization efficiency significantly. Providing a common CSI-RS and NZP CSI-RS resource pool not only improves single user flexibility， but also upgrades system efficiency from the whole network prospective.

Embodiments herein may be implemented in software (executed by one or more processors) ， hardware (e.g.， an application specific integrated circuit) ， or a combination of software and hardware. In an example embodiment， the software (e.g.， application logic， an instruction set) is maintained on any one of various conventional computer-readable media. In the context of this document， a “computer-readable medium” may be any media or means that can contain， store， communicate， propagate or transport the instructions for use by or in connection with an instruction execution system， apparatus， or device， such as a computer， with one example of a computer described and depicted， e.g.， in FIG. 1. A computer-readable medium may comprise a computer-readable storage medium (e.g.，

memories

125， 155， 171 or other device) that may be any media or means that can contain， store， and/or transport the instructions for use by or in connection with an instruction execution system， apparatus， or device， such as a computer. A computer-readable storage medium does not comprise propagating signals.

It is also noted herein that while the above describes example embodiments of the invention， these descriptions should not be viewed in a limiting sense. Rather， there are several variations and modifications which may be made without departing from the scope of the present invention.

If desired， the different functions discussed herein may be performed in a different order and/or concurrently with each other. Furthermore， if desired， one or more of the above-described functions may be optional or may be combined.

Although various aspects of the invention are set out in the independent claims， other aspects of the invention comprise other combinations of features from the described embodiments and/or the dependent claims with the features of the independent claims， and not solely the combinations explicitly set out in the claims.

It is also noted herein that while the above describes example embodiments of the invention， these descriptions should not be viewed in a limiting sense. Rather， there are several variations and modifications which may be made without departing from the scope of the present invention as defined in the appended claims.

The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows：

3GPP 3^rd generation project partner

eNB (or eNodeB) evolved Node B (e.g.， an LTE base station)

BS Base station

CSI Channel state information

CQI Channel quality indicator

CRC Cycling redundancy checking

DCI Downlink control indicator

FDM Frequency division multiplexing

I/F interface

LTE long term evolution

MAC Medium access control

MME mobility management entity

M-MIMO Massive multiple input multiple output

NCE network control element

N/W network

PQI PDSCH resource element mapping and

Quasi-co-location indicator

RRC Radio resource control

RRH remote radio head

Rx receiver

SGW serving gateway

SPS Semi-static persistent scheduled

TDM Time division multiplexing

Tx transmitter

UE user equipment (e.g.， a wireless， typically mobile device)

ZP CSI-RS Zero power channel state information reference signal

Claims

A method， comprising：

dividing communication resources into a plurality of resource pools for transmission of at least one reference signal；

determining a user specific measurement pattern for each of a plurality of user equipments；

assigning the plurality of user equipments to one of the resource pools； and

transmitting an indication of the assigned resource pool and the user specific measurement pattern to each of the plurality of user equipments to configure the plurality of user equipments to measure and report quality information using the communication resource within the assigned resource pool.
The method of claim 1， wherein the at least one reference signal is at least one of： a channel state information reference signal (CSI-RS) for measurement of channel information； and a zero-power channel state information reference signal (ZP-CSI-RS) for measurement of interference information.
The method of claim 2， wherein different user specific measurement patterns are determined based on whether the at least one reference signal is a CSI-RS or a ZP-CSI-RS.
The method of claim 1， wherein the user specific measurement pattern is based at least on traffic characteristics of the respective user equipments.
The method of claim 4， wherein the determining further comprises determining a different user specific measurement pattern for a first user equipment of the plurality of user equipments and a second user equipment of the plurality of user equipments based on different traffic characteristics of the first user equipment and the second user equipment.
The method of claim 1， wherein the plurality of user equipments share the communication resources corresponding to the assigned resource pool using at least one of： time division multiplexing (TDM) and frequency division multiplexing (FDM) .
The method of claim 1， wherein the indication of the assigned resource pool is transmitted via radio resource control (RRC) signaling， and wherein the indication comprises at least one of： an allocation of the communication resource corresponding to the assigned resource pool； a resource index； at least one antenna port to be measured； and a time period.
The method of claim 1， wherein the user specific measurement pattern is at least one of： a periodic CSI measurement pattern； a one-time window measurement pattern； a CSI measurement pattern including a fractional time resource of one periodic CSI-RS resource； a CSI measurement pattern including a fractional frequency resource of one periodic CSI-RS resource.
The method of claim 1， wherein the user specific measurement pattern is transmitted via at least one of： radio resource control signaling， media access control signaling and physical layer signaling.
The method of claim 1， further comprising：

transmitting an indication of a rate matching pattern， wherein the rate matching pattern comprises one or multiple resource pools.
The method of claim 1， further comprising：

transmitting the at least one reference signal； and

receiving a measurement report based on the assigned resource pool and the user specific measurement pattern comprising the quality information from at least one user equipment.
An apparatus comprising：

at least one processor； and

at least one non-transitory memory including computer program code， the at least one memory and the computer program code configured to， with the at least one processor， cause the apparatus to：

divide communication resources into a plurality of resource pools for transmission of at least one reference signal；

determine a user specific measurement pattern for each of a plurality of user equipments；

assign the plurality of user equipments to one of the resource pools； and

transmit an indication of the assigned resource pool and the user specific measurement pattern to each of the plurality of user equipments to configure the plurality of user equipments to measure and report quality information using the communication resource within the assigned resource pool.
The apparatus of claim 12， wherein the at least one reference signal is at least one of： a channel state information reference signal (CSI-RS) for measurement of channel information； and a zero-power channel state information reference signal (ZP-CSI-RS) for measurement of interference information.
The apparatus of claim 13， wherein different user specific measurement patterns are determined based on whether the at least one reference signal is a CSI-RS or a ZP-CSI-RS.
The apparatus of claim 12， wherein the user specific measurement pattern is based at least on traffic characteristics of the respective user equipments.
The apparatus of claim 15， wherein the determination of the user specific measurement pattern for each of a plurality of user equipments comprises determining a different user specific measurement pattern for a first user equipment of the plurality of user equipments and a second user equipment of the plurality of user equipments based on different traffic characteristics of the first user equipment and the second user equipment.
The apparatus of claim 12， wherein the indication of the assigned resource pool is transmitted via radio resource control (RRC) signaling， and wherein the indication comprises at least one of： an allocation of the communication resource corresponding to the assigned resource pool； a resource index； at least one antenna port to be measured； and a time period.
The apparatus of claim 12， wherein the user specific measurement pattern is at least one of：

a periodic CSI measurement pattern； a one-time window measurement pattern； a CSI measurement pattern including a fractional time resource of one periodic CSI-RS resource； a CSI measurement pattern including a fractional frequency resource of one periodic CSI-RS resource.
The apparatus of claim 12， wherein the user specific measurement pattern is transmitted via at least one of： radio resource control signaling， media access control signaling and physical layer signaling.
The apparatus of claim 12， wherein the at least one memory and the computer program code configured to， with the at least one processor， cause the apparatus to：

transmit an indication of a rate matching pattern， wherein the rate matching pattern comprises one or multiple resource pools.
A method comprising：

receiving， by a user equipment， measurement information comprising an indication of a resource pool corresponding to communication resources and a user specific measurement pattern for measuring at least one reference signal， wherein the communication resources are shared by a plurality of user equipments；

measuring quality information based on the at least one reference signal according to the user specific measurement pattern； and

transmitting， via the shared communication resources， a measurement report based at least on the measuring.
The method of claim 21， wherein the at least one reference signal is at least one of： a channel state information reference signal (CSI-RS) for measurement of channel information； and a zero-power channel state information reference signal (ZP-CSI-RS) for measurement of interference information.
The method of claim 21， wherein the indication of the assigned resource pool is received via radio resource control (RRC) signaling， and wherein the indication comprises at least one of： an allocation of the communication resource corresponding to the assigned resource pool； a resource index； at least one antenna port to be measured； and a time period.
The method of to claim 21， further comprising：

receiving a rate matching pattern information comprising one or more resource pools， and

performing rate matching according to the indicated rate matching pattern.
The method of claim 21， wherein the communication resources are shared by the plurality of user equipments using at least one of： time division multiplexing (TDM) and frequency division multiplexing (FDM) .
The method of claim 21， wherein the user specific measurement pattern is at least one of：

a periodic CSI measurement pattern； a one-time window measurement pattern； a CSI measurement pattern including a fractional time resource of one periodic CSI-RS resource； a CSI measurement pattern including a fractional frequency resource of one periodic CSI-RS resource.
The method of claim 21， wherein the user specific measurement pattern is received via at least one of： radio resource control signaling， media access control signaling and physical layer signaling.
An apparatus comprising：

at least one processor； and

at least one non-transitory memory including computer program code， the at least one memory and the computer program code configured to， with the at least one processor， cause the apparatus to：

receive， by a user equipment， measurement information comprising an indication of a resource pool corresponding to communication resources and a user specific measurement pattern for measuring at least one reference signal， wherein the communication resources are shared by a plurality of user equipments；

measure quality information based on the at least one reference signal according to the user specific measurement pattern； and

transmit， via the shared communication resources， a measurement report based at least on the measuring.
The apparatus of claim 28， wherein the at least one reference signal is at least one of： a channel state information reference signal (CSI-RS) for measurement of channel information； and a zero-power channel state information reference signal (ZP-CSI-RS) for measurement of interference information.
The apparatus of claim 28， wherein the indication of the assigned resource pool is received via radio resource control (RRC) signaling， and wherein the indication comprises at least one of： an allocation of the communication resource corresponding to the assigned resource pool； a resource index； at least one antenna port to be measured； and a time period.
The apparatus of claim 28， wherein the at least one memory and the computer program code configured to， with the at least one processor， cause the apparatus to：

receive a rate matching pattern information comprising one or more resource pools， and perform rate matching according to the indicated rate matching pattern.
The apparatus of claim 28， wherein the user specific measurement pattern is at least one of：

a periodic CSI measurement pattern； a one-time window measurement pattern； a CSI measurement pattern including a fractional time resource of one periodic CSI-RS resource； a CSI measurement pattern including a fractional frequency resource of one periodic CSI-RS resource.
A communication system comprising an apparatus in accordance with any one of claims 12 to 20 and an apparatus in accordance with any one of claims 28-32.
A computer program comprising program code for executing the method according to any of claims 1 to 11 or 21 to 27.
The computer program according to claim 34， wherein the computer program is a computer program product comprising a computer-readable medium bearing computer program code embodied therein for use with a computer.