WO2021160264A1

WO2021160264A1 - Monitoring throughput

Info

Publication number: WO2021160264A1
Application number: PCT/EP2020/053757
Authority: WO
Inventors: Martin Kollar
Original assignee: Nokia Technologies Oy
Priority date: 2020-02-13
Filing date: 2020-02-13
Publication date: 2021-08-19

Abstract

There is disclosed an apparatus. The apparatus comprises means for monitoring downlink throughput to a user equipment at two or more layers of the apparatus, by determining at least one ratio of scheduled throughput volume to at least one time-duration of a burst of data transmitted by the apparatus.

Description

Monitorinq throughput

Field

This disclosure relates to communications. More particularly the present disclosure relates to monitoring scheduled throughput in a communication system.

Background

A communication system can be seen as a facility that enables communication between two or more devices such as user terminals, machine-like terminals, base stations and/or other nodes by providing communication channels for carrying information between the communicating devices. A communication system can be provided for example by means of a communication network and one or more compatible communication devices. The communication may comprise, for example, communication of data for carrying data for voice, electronic mail (email), text message, multimedia and/or content data communications and so on. Non-limiting examples of services provided include two-way or multi-way calls, data communication or multimedia services and access to a data network system, such as the Internet.

In a wireless system at least a part of communications occurs over wireless interfaces. Examples of wireless systems include public land mobile networks (PLMN), satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). A local area wireless networking technology allowing devices to connect to a data network is known by the tradename WiFi (or Wi-Fi). WiFi is often used synonymously with WLAN. The wireless systems can be divided into cells, and are therefore often referred to as cellular systems. A base station provides at least one cell.

A user can access a communication system by means of an appropriate communication device or terminal capable of communicating with a base station. Hence nodes like base stations are often referred to as access points. A communication device of a user is often referred to as user equipment (UE). A communication device is provided with an appropriate signal receiving and transmitting apparatus for enabling communications, for example enabling communications with the base station and/or communications directly with other user devices. The communication device can communicate on appropriate channels, e.g. listen to a channel on which a station, for example a base station of a cell, transmits. A communication system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and/or parameters which shall be used for the connection are also typically defined. Non-limiting examples of standardised radio access technologies include GSM (Global System for Mobile), EDGE (Enhanced Data for GSM Evolution) Radio Access Networks (GERAN), Universal Terrestrial Radio Access Networks (UTRAN) and evolved UTRAN (E-UTRAN). An example communication system architecture is the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology. The LTE is standardized by the third Generation Partnership Project (3GPP). The LTE employs the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access and a further development thereof which is sometimes referred to as LTE Advanced (LTE- A).

Since introduction of fourth generation (4G) services increasing interest has been paid to the next, or fifth generation (5G) standard. 5G may also be referred to as a New Radio (NR) network.

End-user throughput is a key performance indicator (KPI) used to monitor quality of service (QoS) perceived or experienced by the end user. Statement of invention

According to a first aspect there is provided an apparatus comprising means for performing: monitoring downlink throughput to a user equipment at two or more layers of the apparatus, by determining at least one ratio of scheduled throughput volume to at least one time-duration of a burst of data transmitted by the apparatus. According to some examples, the two or more layers comprise any two or more of: a packet data convergence protocol layer; a radio link control layer; a media access control layer. According to some examples, the means are further configured to perform determining that there is throughput degradation, based on a value of the determined at least one ratio.

According to some examples, the means are further configured to perform, in response to determining the throughput degradation, initiating an action to fix the throughput degradation.

According to some examples, the means are further configured to perform determining a first ratio, wherein the one or more data units comprise one or more packet data convergence protocol data units, and the at least one time duration of the burst of data starts at a beginning of a first packet data convergence protocol data unit in the burst, and the time duration of the burst of data ends at an end of a last but one packet data convergence protocol data unit in the burst.

According to some examples, the one or more packet data convergence protocol data units comprises a single packet data convergence protocol data unit mapped to a last radio link control packet data unit of the burst.

According to some examples, the means are further configured to perform determining a first ratio, wherein the one or more data units comprise two or more packet data convergence protocol data units mapped to a last but one radio link control packet data unit of the burst, and the at least one time duration of the burst of data starts at a beginning of a first packet data convergence protocol data unit of the two or more packet data convergence protocol data units in the burst, and the time duration of the burst of data ends at a point in time when the first packet data convergence protocol data unit is transmitted to a radio link control layer.

According to some examples, the means are further configured to perform determining a second ratio, wherein the one or more data units comprise one or more radio link control data units, and the at least one time duration of the burst of data starts at a beginning of a first radio link control data unit in the burst, and the time duration of the burst of data ends at an end of a last but one radio link control data unit of the burst. According to some examples, the burst of data comprises one or more packet data convergence protocol data units, and a time duration of the burst of data starts when a first packet data convergence protocol data unit in the burst of data arrives in an empty packet data convergence protocol buffer, and the time duration of the burst of data ends when the packet data convergence protocol buffer is next empty.

According to some examples, the means are further configured to perform only performing the determining at least one ratio when it is determined by the apparatus that the burst of data is split across two or more transmission time intervals.

According to some examples, the means are further configured to perform reporting the determined at least one ratio to another apparatus, for enabling the another apparatus to determine one or more layers of the apparatus experiencing throughput issues.

According to some examples, the apparatus comprises a base station.

According to some examples, the means comprises at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

According to a second aspect there is provided an apparatus comprising at least one processor; and at least one 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 at least to perform: monitoring downlink throughput to a user equipment at two or more layers of the apparatus, by determining at least one ratio of scheduled throughput volume to at least one time-duration of a burst of data transmitted by the apparatus.

According to some examples, the two or more layers comprise any two or more of: a packet data convergence protocol layer; a radio link control layer; a media access control layer.

According to some examples, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform determining that there is throughput degradation, based on a value of the determined at least one ratio. According to some examples, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform, in response to determining the throughput degradation, initiating an action to fix the throughput degradation.

According to some examples, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform determining a first ratio, wherein the one or more data units comprise one or more packet data convergence protocol data units, and the at least one time duration of the burst of data starts at a beginning of a first packet data convergence protocol data unit in the burst, and the time duration of the burst of data ends at an end of a last but one packet data convergence protocol data unit in the burst.

According to some examples, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform determining a first ratio, wherein the one or more data units comprise two or more packet data convergence protocol data units mapped to a last but one radio link control packet data unit of the burst, and the at least one time duration of the burst of data starts at a beginning of a first packet data convergence protocol data unit of the two or more packet data convergence protocol data units in the burst, and the time duration of the burst of data ends at a point in time when the first packet data convergence protocol data unit is transmitted to a radio link control layer.

According to some examples, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform determining a second ratio, wherein the one or more data units comprise one or more radio link control data units, and the at least one time duration of the burst of data starts at a beginning of a first radio link control data unit in the burst, and the time duration of the burst of data ends at an end of a last but one radio link control data unit of the burst.

According to some examples, the burst of data comprises one or more packet data convergence protocol data units, and a time duration of the burst of data starts when a first packet data convergence protocol data unit in the burst of data arrives in an empty packet data convergence protocol buffer, and the time duration of the burst of data ends when the packet data convergence protocol buffer is next empty.

According to some examples, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform only performing the determining at least one ratio when it is determined by the apparatus that the burst of data is split across two or more transmission time intervals.

According to some examples, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to perform reporting the determined at least one ratio to another apparatus, for enabling the another apparatus to determine one or more layers of the apparatus experiencing throughput issues.

According to some examples, the apparatus comprises a base station. According to a third aspect there is provided an apparatus comprising circuitry for monitoring downlink throughput to a user equipment at two or more layers of the apparatus, by determining at least one ratio of scheduled throughput volume to at least one time-duration of a burst of data transmitted by the apparatus.

According to a fourth aspect there is provided a method comprising: at an apparatus, monitoring downlink throughput to a user equipment at two or more layers of the apparatus, by determining at least one ratio of scheduled throughput volume to at least one time-duration of a burst of data transmitted by the apparatus.

According to some examples, the method comprises determining that there is throughput degradation, based on a value of the determined at least one ratio.

According to some examples the method comprises, in response to determining the throughput degradation, initiating an action to fix the throughput degradation. According to some examples the method comprises determining a first ratio, wherein the one or more data units comprise one or more packet data convergence protocol data units, and the at least one time duration of the burst of data starts at a beginning of a first packet data convergence protocol data unit in the burst, and the time duration of the burst of data ends at an end of a last but one packet data convergence protocol data unit in the burst.

According to some examples, the one or more packet data convergence protocol data units comprise a single packet data convergence protocol data unit mapped to a last radio link control packet data unit of the burst. According to some examples the method comprises determining a first ratio, wherein the one or more data units comprise two or more packet data convergence protocol data units mapped to a last but one radio link control packet data unit of the burst, and the at least one time duration of the burst of data starts at a beginning of a first packet data convergence protocol data unit of the two or more packet data convergence protocol data units in the burst, and the time duration of the burst of data ends at a point in time when the first packet data convergence protocol data unit is transmitted to a radio link control layer.

According to some examples the method comprises determining a second ratio, wherein the one or more data units comprise one or more radio link control data units, and the at least one time duration of the burst of data starts at a beginning of a first radio link control data unit in the burst, and the time duration of the burst of data ends at an end of a last but one radio link control data unit of the burst.

According to some examples the burst of data comprises one or more packet data convergence protocol data units, and a time duration of the burst of data starts when a first packet data convergence protocol data unit in the burst of data arrives in an empty packet data convergence protocol buffer, and the time duration of the burst of data ends when the packet data convergence protocol buffer is next empty.

According to some examples the method comprises only performing the determining at least one ratio when it is determined that the burst of data is split across two or more transmission time intervals. According to some examples the method comprises reporting the determined at least one ratio to another apparatus, for enabling the another apparatus to determine one or more layers of the apparatus experiencing throughput issues.

According to some examples the method is performed by a base station.

According to a fifth aspect there is provided a computer program comprising instructions for causing an apparatus to perform at least the following: monitoring downlink throughput to a user equipment at two or more layers of the apparatus, by determining at least one ratio of scheduled throughput volume to at least one time- duration of a burst of data transmitted by the apparatus.

According to sixth aspect there is provided a computer program comprising instructions stored thereon for performing at least the following: monitoring downlink throughput to a user equipment at two or more layers of an apparatus, by determining at least one ratio of scheduled throughput volume to at least one time-duration of a burst of data transmitted by the apparatus.

According to a seventh aspect there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the following: monitoring downlink throughput to a user equipment at two or more layers of the apparatus, by determining at least one ratio of scheduled throughput volume to at least one time-duration of a burst of data transmitted by the apparatus.

According to an eighth aspect there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least the following: monitoring downlink throughput to a user equipment at two or more layers of an apparatus, by determining at least one ratio of scheduled throughput volume to at least one time-duration of a burst of data transmitted by the apparatus.

Brief description of Figures

The invention will now be described in further detail, by way of example only, with reference to the following examples and accompanying drawings, in which: Figure 1 shows a schematic example of a wireless communication system where the invention may be implemented;

Figure 2 schematically shows the principle of IP scheduled throughput measurement in DL;

Figure 3 schematically shows the principle of measurement of a burst duration;

Figure 4 schematically shows correlation between degradation in scheduled IP throughput with changes at the PDCP and RLC layers;

Figure 5 shows an example of a communication device;

Figure 6 shows an example of a control apparatus;

Figure 7 is a flow-chart of a method according to an example.

Detailed description

Before explaining in detail the examples, certain general principles of a wireless communication system and mobile communication devices are briefly explained with reference to Figures 1 to 2 to assist in understanding the technology underlying the described examples.

In a wireless communication system 100, such as that shown in Figure 1 , a wireless communication devices, for example, user equipment (UE) or MTC devices 102, 104, 105 are provided wireless access via at least one base station or similar wireless transmitting and/or receiving wireless infrastructure node or point. Such a node can be, for example, a base station or an eNodeB (eNB), or in a 5G system a Next Generation NodeB (gNB), or other wireless infrastructure node. These nodes will be generally referred to as base stations. Base stations are typically controlled by at least one appropriate controller apparatus, so as to enable operation thereof and management of mobile communication devices in communication with the base stations. The controller apparatus may be located in a radio access network (e.g. wireless communication system 100) or in a core network (CN) (not shown) and may be implemented as one central apparatus or its functionality may be distributed over several apparatus. The controller apparatus may be part of the base station and/or provided by a separate entity such as a Radio Network Controller. In Figure 1 control apparatus 108 and 109 are shown to control the respective macro level base stations 106 and 107. In some systems, the control apparatus may additionally or alternatively be provided in a radio network controller. Other examples of radio access system comprise those provided by base stations of systems that are based on technologies such as 5G or new radio, wireless local area network (WLAN) and/or WiMax (Worldwide Interoperability for Microwave Access). A base station can provide coverage for an entire cell or similar radio service area.

In Figure 1 base stations 106 and 107 are shown as connected to a wider communications network 113 via gateway 112. A further gateway function may be provided to connect to another network. The smaller base stations 116, 118 and 120 may also be connected to the network 113, for example by a separate gateway function and/or via the controllers of the macro level stations. The base stations 116, 118 and 120 may be pico or femto level base stations or the like. In the example, stations 116 and 118 are connected via a gateway 111 whilst station 120 connects via the controller apparatus 108. In some embodiments, the smaller stations may not be provided.

“Throughput” may be considered a rate of successful message delivery over a communication channel. In a communication channel, throughput may be measured on the downlink (DL) e.g. from base station to UE, or measured on the uplink (UL) e.g. from UE to base station. In Figure 1, DL throughput is schematically shown by arrow 122, and UL throughput is schematically shown by arrow 124. The present disclosure is concerned with measuring DL throughput, and more particularly with measuring DL throughput of internet protocol (IP) traffic.

End-user throughput is one Key Performance Indicator (KPI) used to monitor quality of service (QoS) perceived by the end-user. The services provided by E- UTRAN are based on IP packet delivery. Therefore, what the end-user perceives or experiences may be measured as an IP throughput.

The 3GPP TS 36.314 defines a way to measure so called “IP Scheduled Throughput” per QCI within chapter 4.1.6, and 3GPP TS 32.450 chapter 6.3.1. IP scheduled throughput in DL is schematically summarized in Figure 2. As shown in Figure 2, ThpVolDI (Throughput Volume in DL, as defined in 3GPP

TS 36.314) is equal to the sum of successful transmissions (kbits) when the buffer is not empty. The buffer referred to is the buffer in any layer within a base station. Therefore the buffer can be PDCP, RLC or MAC buffer. The total transferred DL volume is equal to the sum of successful transmissions when the buffer is not empty plus successful transmissions when the buffer is empty. The IP throughput in DL is calculated as:

IP throughput in DL = ThpVolDI / ThpTimeDI (kbits/s)

ThpTimeDI is throughput time in DL. According to 3GPP 36.314, ThpTimeDI is time data in the buffer excluding last TTIs emptying the buffer.

In a similar way, the “PDCP (packet data convergence protocol) buffered end user throughput in DL” is measured in 5G according to 3GPP TS 28.552 (discussion ongoing in 3GPP SA5).

The IP Scheduled Throughput as defined in 3GPP TS 36.314 in 4G and 3GPP TS 28.552 in 5G is currently considered a good indicator for throughput monitoring as perceived by end user in E-UTRAN and NR, respectively. Also, the ranges for different services (QCIs (QoS class identifier) in E-UTRAN and 5Qis (5G quality of service identifiers) in NR) where the throughput is yet sufficient to provide the requested QoS and where not, is well understood and defined by operators. However, as identified in the present disclosure, a problem is what actions shall be taken if the throughput is within a range that cannot provide the requested or needed QoS. This is at least in part because a philosophy of IP scheduled throughput measurement is to obtain it as a ratio of PDCP SDU (service data unit) volume and time, when there is data in the buffer. While the PDCP SDU volume counted in PDCP layer according to successful transmission/ reception communicated form lower layers the time there are data in the buffer measured in MAC and RLC layer. The throughput is impacted by all layers in the base station. For example, despite the throughput volume being counted as PDCP SDU volume, it considers only those PDCP SDU frames that were successfully received by UE, which is communicated from RLC and MAC layers via some ACK messages. The throughput time is then measured in MAC and RLC layers and represents a time period there is data in the buffer for the given burst, excluding last TTI emptying the buffer. This means that because there are heavy interactions between the layers, and potentially on many occasions, it is not straightforward to identify what actions to follow to fix the issue of degraded IP scheduled throughput.

Currently, the actions that are followed by operators after observing a degradation in IP scheduled throughput in DL focus on monitoring the following main indicators: • DL PDCP SDU delay per QCI (according to 3GPP TS 36.314 in E- UTRAN and 3GPP TS 28.552 in NR)

PDCP SDU volume in DL (according to 3GPP TS 32.425 in E-UTRAN and 3GPP TS 28.552 in NR)

PDCP SDU Loss Rate in DL (according to 3GPP TS 36.314 in E-UTRAN and 3GPP TS 28.552 in NR)

• PDCP SDU Discard Ratio in DL (according to 3GPP TS 36.314 in E- UTRAN and 3GPP TS 28.552 in NR)

In parallel, some other indicators related to radio quality based on CQI (channel quality indicator), RSSI (received signal strength indicator), SINR (signal to interference plus noise ratio), RSRP (reference signal received power) and RSRQ (reference signal received quality) may be monitored.

For scenarios when degradation of the IP scheduled throughput resulted from an overall radio quality issue, bringing the IP scheduled throughput into a requested level can be achieved. The issue may be observed in parallel, visible due to observed degradation in some of the above-mentioned radio quality indicators. However, in many cases IP scheduled throughput degradation is not connected to any notable radio quality degradation, but to some parameters changing in existing or newly enabled features or scheduler changes or some other impacts. To find a root cause in such a case may be difficult and time consuming, as the number of indicators, parameters and additional tests to be executed may be huge. It is also identified in the present disclosure that the monitoring of the PDCP SDU Delay, volume loss and discard rate indicators may not help either to identify the issue, as those indicators are based on PDCP SDU packet while the IP scheduled throughput is based on burst duration. The present disclosure further identifies that it may be useful for operators to be able to identify into which part of a base station (BTS) the problem is related, with a satisfactory or high probability.

Therefore, as will be discussed in more detail below, the present disclosure proposes a new method for extended monitoring of IP scheduled throughput in DL. The extended monitoring is based on two additional parts of throughput.

First, so called PDCP SDU application layer duration related throughput is obtained as a ratio of the IP scheduled throughput volume and total burst time. A total burst time in an observation period is measured for each burst. According to examples, the burst time starts from a point in time where a first part (i.e. beginning) of the burst is transmitted to the UE. According to examples the burst time is considered to end at the last but one (i.e. penultimate) PDCP PDU of the burst transmitted to RLC layer in DL direction. In other words, the throughput is taken as IP scheduled throughput volume in DL (as defined in 3GPP TS 36.314) over a time period the PDCP SDUs (except the last PDCP SDU) of all involved bursts in the observation period spent in the PDCP layer. For comparison, when determining the IP scheduled throughput according to 3GPP, the end point of the burst is considered the point when the last but one part of the burst has been successfully transmitted to the UE, which has been HARQ ACK by the UE.

Secondly, the so called RLC (radio link control) SDU/ middle layer duration related throughput is obtained as a ratio of the IP scheduled throughput volume in DL (as defined in 3GPP TS 36.314) and total bursts of time in the observation period measured. In examples, the observation period is considered to start at a point in time at the first part (i.e. beginning) of the burst transmitted to UE. The end of the observation window is considered the last but one RLC PDU of the burst transmitted to MAC layer in DL direction. In other words, the throughput is taken as IP scheduled throughput volume in DL over time period the RLC SDUs of all involved bursts (except the last RLC SDU) are spent in the RLC layer in the observation window. For comparison, when determining the IP scheduled throughput according to 3GPP, the end point of the burst is considered the point when the last but one part of the burst has been successfully transmitted to the UE, which has been HARQ ACK by the UE.

It will be noted that the disclosure is not restricted to E-UTRAN and the above two indicators only, which are provided as examples. For example, the method can be applied to 5G as well, with division not to only PDCP SDU/application and RLC/middle layer. In general, there are not limits to further divisions inside RLC or even MAC layer. In practice, such division may depend on subsystem definition which is vendor specific. Some more detailed examples will now be provided, starting with a description of Figure 2 which demonstrates the principle of measurement of one burst duration as part of denominator of the PDCP SDU/ application layer duration related throughput in DL, and RLC SDU/ middle layer duration related throughput in DL indicators. In examples, the number of PDCP SDU is equal to the number of PDCP PDU and equal to the number of RLC SDU. In the example of Figure 3 there are three PDCP SDUs, namely PDCP SDU1 330, PDCP SDU2 332, and PDCP SDU3 334. In this example there are three PDCP PDUs, namely PDCP PDU1 336, PDCP PDU2 338, and PDCP PDU3 340. In this example there are three RLC SDUs, namely RLC SDU1 342, RLC SDU2 344 and RLC SDU3 346. There are two RLC PDUs, namely RLC PDU1 348 and RLC PDU2 350. In examples, the ratio of RLC PDUs to RLC SDUs is dependent on a size of the PDCP SDUs. If the PDCP SDUs are small then perhaps a couple of PDCP SDUs will be mapped to one RLC SDU. If the PDCP SDUs are big then there may be one to one mapping to RLC PDUs. The Media Access Control (MAC) layer is schematically shown at 352. In the example of Figure 3, the DUs shown are moved to the MAC layer for addition coding. For the burst example of Figure 3, the DUs are being transmitted from BTS to UE.

PDCP SDU application layer

In the example of Figure 3, the PDCP SDU (application layer) duration related throughput in DL is as follows:

DL throughput = IP scheduled throughput in DL / total burst time in observation period

The IP scheduled throughput in DL is as defined in 3GPP TS 36.314. The total burst time in the observation period is measured from the point in time from the start of the burst (to) transmitted to UE, until the end of the last but one of the PDCP PDU of the burst transmitted to the RLC layer. “Last but one” may also be referred to as penultimate. In the example of Figure 3, that is ti . Therefore, in the example of Figure 3 the PDCP SDU application layer observation period = ti - 1₀.

Therefore, in the example of Figure 3:

PDCP SDU application layer throughput = IP scheduled throughput in DL / (ti - 1₀₎ RLC SDU middle layer

In the example of Figure 3, the RLC SDU (middle layer) duration related throughput in DL is as follows:

DL throughput = IP scheduled throughput in DL / total burst time in observation window

The IP scheduled throughput in DL is as defined in 3GPP TS 36.314. The total burst time in the observation period is measured from the point in time from the start of the burst (t₀) transmitted to UE, until the end of the last but one RLC PDU of the burst transmitted to MAC layer in DL. “Last but one” may also be referred to as penultimate. In the example of Figure 3, that is t2. Therefore, in the example of Figure 3 the RLC SDU observation period = t2 - to.

Therefore, in the example of Figure 3:

RLC SDU middle layer throughput = IP scheduled throughput in DL / (t2 - to)

It will be appreciated from the above two examples that the DL throughput is measured by dividing the IP scheduled throughput in DL by the burst duration. In other words, the burst duration is the denominator.

Figure 4 schematically shows a graph plotting throughput against time. Within the plot of Figure 4 are three different situations marked as 3a, 3b, and 3c, which are discussed in more detail below. Within each of 3a to 3c, the top line represents PDCP SDU (application layer) duration related throughput in DL; the middle line represents RLC SDU (middle layer) duration related throughput in DL, and the lowest line represents IP scheduled throughput in DL. The vertical, dashed line represents a point in time where there is degradation of the IP scheduled throughput in DL.

As shown in 3a of Figure 4, the PDCP SDU (application layer) duration related throughput in DL and RLC SDU (middle layer) duration related throughput in DL are about the same before and after the degradation in IP scheduled throughput in DL. Therefore, the probability is that the problem is located in the MAC layer. As shown in 3b of Figure 4, the PDCP SDU (application layer) duration related throughput in DL is significantly less after the degradation in IP scheduled throughput in DL. Therefore, in this case the probability is that the degradation problem is located in the PDCP layer. A reason may be, for example, an increased PDCP discard timer.

As shown in 3c of Figure 4, the RLC SDU (middle layer) duration related throughput in DL is significantly less after the degradation in IP scheduled throughput in DL. Therefore the probability is that the problem is located in the RLC layer.

The burst durations will now be discussed in more detail.

Total IP burst duration time in PDCP layer in DL

Protocol Layer: PDCP, RLC, MAC

An objective of this measurement is to measure total burst duration time in PDCP layer. In examples, initial buffering time in eNB is excluded. In examples, only bursts that are large enough to require transmissions to be split across several TTIs are covered within this measurement. This means that minor bursts which may not be indicative of performance are not included, which may save processing and/or memory load. In examples, for an eNB serving one or more RNs (radio networks), packets transmitted between the eNB and RNs are excluded. That is, in examples, only packets transmitted between the eNB and UE(s) are counted.

As discussed above, this measurement (PDCP burst duration time) can be used as a denominator of the IP scheduled throughput measurement.

This determination of throughput may help identify possible problems in the layers (e.g. PDCP) in case of degradation of the IP scheduled throughput.

Some definitions are provided in Table 1 and Table 2 below.

Table 1

Table 2

Total IP burst duration time in RLC Laver in DL

Protocol Layer: PDCP, RLC, MAC

An objective of this measurement is to measure total burst duration time in RLC layer. In examples, initial buffering time in eNB is excluded. In examples, for an eNB serving one or more RNs, packets transmitted between the eNB and RNs are excluded. That is, in examples, only packets transmitted between the eNB and UE(s) are counted. In examples, only bursts that are large enough to require transmissions to be split across several TTIs are covered within this measurement.

As discussed above, in examples this measurement (RLC burst duration time) can be used as a denominator of the IP scheduled throughput measurement. This determination of throughput may help identify possible problems in the layers (e.g. RLC) in case of degradation of the IP scheduled throughput.

Some definitions are provided in Table 3 and Table 4 below.

Table 3

Table 4

Overall, it will be appreciated that measuring the PDCP and RLC layer throughputs as discussed above can help an operator to monitor how each layer (e.g. part of eNB) contributes to IP scheduled throughput in DL, and identify possible problems in the layers in case of degradation of the IP scheduled throughput.

A possible wireless communication device will now be described in more detail with reference to Figure 5 showing a schematic, partially sectioned view of a communication device 500. Such a communication device is often referred to as user equipment (UE) or terminal. An appropriate mobile communication device may be provided by any device capable of sending and receiving radio signals. Non-limiting examples comprise a mobile station (MS) or mobile device such as a mobile phone or what is known as a ’smart phone’, a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), personal data assistant (PDA) or a tablet provided with wireless communication capabilities, or any combinations of these or the like. A mobile communication device may provide, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and so on. Users may thus be offered and provided numerous services via their communication devices. Non-limiting examples of these services comprise two-way or multi-way calls, data communication or multimedia services or simply an access to a data communications network system, such as the Internet. Users may also be provided broadcast or multicast data. Non-limiting examples of the content comprise downloads, television and radio programs, videos, advertisements, various alerts and other information.

A wireless communication device may be for example a mobile device, that is, a device not fixed to a particular location, or it may be a stationary device. The wireless device may need human interaction for communication, or may not need human interaction for communication. In the present teachings the terms UE or “user” are used to refer to any type of wireless communication device.

The wireless device 500 may receive signals over an air or radio interface 507 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In Figure 5 transceiver apparatus is designated schematically by block 506. The transceiver apparatus 506 may be provided for example by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the wireless device.

A wireless device is typically provided with at least one data processing entity 501 , at least one memory 502 and other possible components 503 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The data processing, storage and other relevant control apparatus can be provided on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 504. The user may control the operation of the wireless device by means of a suitable user interface such as key pad 505, voice commands, touch sensitive screen or pad, combinations thereof or the like. A display 508, a speaker and a microphone can be also provided. Furthermore, a wireless communication device may comprise appropriate connectors (either wired or wireless) to other devices and/or for connecting external accessories, for example hands-free equipment, thereto.

Figure 6 shows an example of a control apparatus for a communication system, for example to be coupled to and/or for controlling a station of an access system, such as a RAN node, e.g. a base station, gNB, a central unit of a cloud architecture or a node of a core network such as an MME or S-GW, a scheduling entity such as a spectrum management entity, or a server or host. The control apparatus may be integrated with or external to a node or module of a core network or RAN. In some embodiments, base stations comprise a separate control apparatus unit or module. In other embodiments, the control apparatus can be another network element such as a radio network controller or a spectrum controller. In some embodiments, each base station may have such a control apparatus as well as a control apparatus being provided in a radio network controller. The control apparatus 600 can be arranged to provide control on communications in the service area of the system. The control apparatus 600 comprises at least one memory 601 , at least one data processing unit 602, 603 and an input/output interface 604. Via the interface the control apparatus can be coupled to a receiver and a transmitter of the base station. The receiver and/or the transmitter may be implemented as a radio front end or a remote radio head. For example, the control apparatus 600 or processor 601 can be configured to execute an appropriate software code to provide the control functions.

Figure 6 is a flow chart of a method according to an example embodiment. The flow chart of Figure 6 may be carried out, in an example embodiment, by a base station.

As shown at S1 , the method comprises monitoring downlink throughput to a user equipment at two or more layers of the apparatus.

As shown at S2, the method comprises determining at least one ratio of scheduled throughput volume to at least one time-duration of a burst of data transmitted by the apparatus.

In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects of the invention 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, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, 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. As used in this application, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and(b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation. This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

The embodiments of this invention may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Computer software or program, also called program product, including software routines, applets and/or macros, may be stored in any apparatus-readable data storage medium and they comprise program instructions to perform particular tasks. A computer program product may comprise one or more computer-executable components which, when the program is run, are configured to carry out embodiments. The one or more computer-executable components may be at least one software code or portions of it.

Further in this regard it should be noted that any blocks of the logic flow as in the Figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD. The physical media is a non-transitory media.

The memory 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, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may comprise one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), FPGA, gate level circuits and processors based on multi core processor architecture, as non-limiting examples. Embodiments of the inventions may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

The foregoing description has provided by way of non-limiting examples a full and informative description of the exemplary embodiment of this invention. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this invention will still fall within the scope of this invention as defined in the appended claims. Indeed there is a further embodiment comprising a combination of one or more embodiments with any of the other embodiments previously discussed.

Claims

1. An apparatus comprising means for performing: monitoring downlink throughput to a user equipment at two or more layers of the apparatus, by determining at least one ratio of scheduled throughput volume to at least one time-duration of a burst of data transmitted by the apparatus.

2. An apparatus according to claim 1, wherein the two or more layers comprise any two or more of: a packet data convergence protocol layer; a radio link control layer; a media access control layer.

3. An apparatus according to claim 1 or claim 2, wherein the means are further configured to perform determining that there is throughput degradation, based on a value of the determined at least one ratio.

4. An apparatus according to claim 3, wherein the means are further configured to perform, in response to determining the throughput degradation, initiating an action to fix the throughput degradation.

5. An apparatus according to any of claims 1 to 4, wherein the means are further configured to perform determining a first ratio, wherein the one or more data units comprise one or more packet data convergence protocol data units, and the at least one time duration of the burst of data starts at a beginning of a first packet data convergence protocol data unit in the burst, and the time duration of the burst of data ends at an end of a last but one packet data convergence protocol data unit in the burst.

6. An apparatus according to claim 5, wherein the one or more packet data convergence protocol data units comprises a single packet data convergence protocol data unit mapped to a last radio link control packet data unit of the burst.

7. An apparatus according to any of claims 1 to 4, wherein the means are further configured to perform determining a first ratio, wherein the one or more data units comprise two or more packet data convergence protocol data units mapped to a last but one radio link control packet data unit of the burst, and the at least one time duration of the burst of data starts at a beginning of a first packet data convergence protocol data unit of the two or more packet data convergence protocol data units in the burst, and the time duration of the burst of data ends at a point in time when the first packet data convergence protocol data unit is transmitted to a radio link control layer.

8. An apparatus according to any of claims 1 to 7, wherein the means are further configured to perform determining a second ratio, wherein the one or more data units comprise one or more radio link control data units, and the at least one time duration of the burst of data starts at a beginning of a first radio link control data unit in the burst, and the time duration of the burst of data ends at an end of a last but one radio link control data unit of the burst.

9. An apparatus according to any one of claims 1 to 8, wherein the burst of data comprises one or more packet data convergence protocol data units, and a time duration of the burst of data starts when a first packet data convergence protocol data unit in the burst of data arrives in an empty packet data convergence protocol buffer, and the time duration of the burst of data ends when the packet data convergence protocol buffer is next empty.

10. An apparatus according to any one of claims 1 to 9, wherein the means are further configured to perform only performing the determining at least one ratio when it is determined by the apparatus that the burst of data is split across two or more transmission time intervals.

11. An apparatus according to any one of claims 1 to 10, wherein the means are further configured to perform reporting the determined at least one ratio to another apparatus, for enabling the another apparatus to determine one or more layers of the apparatus experiencing throughput issues.

12. An apparatus according to any of claims 1 to 11, wherein the apparatus comprises a base station.

13. An apparatus according to any of claims 1 to 12, wherein the means comprises at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

14. A method comprising: at an apparatus, monitoring downlink throughput to a user equipment at two or more layers of the apparatus, by determining at least one ratio of scheduled throughput volume to at least one time-duration of a burst of data transmitted by the apparatus.

15. A method according to claim 14, wherein the two or more layers comprise any two or more of: a packet data convergence protocol layer; a radio link control layer; a media access control layer.

16. A method according to claim 14 or claim 15, wherein the method comprises determining that there is throughput degradation, based on a value of the determined at least one ratio.

17. A method according to claim 16 comprising, in response to determining the throughput degradation, initiating an action to fix the throughput degradation.

18. A method according to any of claims 14 to 17, comprising determining a first ratio, wherein the one or more data units comprise one or more packet data convergence protocol data units, and the at least one time duration of the burst of data starts at a beginning of a first packet data convergence protocol data unit in the burst, and the time duration of the burst of data ends at an end of a last but one packet data convergence protocol data unit in the burst.

19. A method according to claim 18, wherein the one or more packet data convergence protocol data units comprise a single packet data convergence protocol data unit mapped to a last radio link control packet data unit of the burst.

20. A method according to any of claims 14 to 17, comprising determining a first ratio, wherein the one or more data units comprise two or more packet data convergence protocol data units mapped to a last but one radio link control packet data unit of the burst, and the at least one time duration of the burst of data starts at a beginning of a first packet data convergence protocol data unit of the two or more packet data convergence protocol data units in the burst, and the time duration of the burst of data ends at a point in time when the first packet data convergence protocol data unit is transmitted to a radio link control layer.

21. A method according to any of claims 14 to 20, comprising determining a second ratio, wherein the one or more data units comprise one or more radio link control data units, and the at least one time duration of the burst of data starts at a beginning of a first radio link control data unit in the burst, and the time duration of the burst of data ends at an end of a last but one radio link control data unit of the burst.

22. A method according to any one of claims 14 to 21 , wherein the burst of data comprises one or more packet data convergence protocol data units, and a time duration of the burst of data starts when a first packet data convergence protocol data unit in the burst of data arrives in an empty packet data convergence protocol buffer, and the time duration of the burst of data ends when the packet data convergence protocol buffer is next empty.

23. A method according to any one of claims 14 to 22, comprising only performing the determining at least one ratio when it is determined that the burst of data is split across two or more transmission time intervals.

24. A method according to any one of claims 14 to 23, comprising reporting the determined at least one ratio to another apparatus, for enabling the another apparatus to determine one or more layers of the apparatus experiencing throughput issues.

25. A method according to any of claims 14 to 24, performed by a base station.

26. A computer program comprising instructions for causing an apparatus to perform at least the following: monitoring downlink throughput to a user equipment at two or more layers of the apparatus, by determining at least one ratio of scheduled throughput volume to at least one time-duration of a burst of data transmitted by the apparatus.