HK1189745B - The method of transmitting power information from the user equipment, the processing method of the received power information and the corresponding user equipment, base stations, systems, and apparatus - Google Patents

Description

Method of communicating power information from user equipment, method of processing received power information, and corresponding user equipment, base station, apparatus and system

Technical Field

The present invention relates to a power headroom control element for communicating power information from a User Equipment (UE) to a Base Station (BS), a method of communicating power information from a UE to a BS, a method of processing received power information at a Radio Access Network (RAN), and to a user equipment for communicating power information and a base station configured to process received power information, which in particular enable simple handling and processing of transmitted power information, respectively.

Background

In a typical cellular radio system, wireless terminals (also referred to as mobile terminals, mobile stations, and/or user equipment units) communicate via a Radio Access Network (RAN) to one or more core networks. The user equipment unit or simply User Equipment (UE) may include a mobile telephone (e.g., a cellular telephone) and/or other processing device (e.g., a portable, pocket, palm-top, laptop computer that communicates voice and/or data with the RAN) that has wireless communication capabilities.

The RAN covers a geographical area which is divided into cell areas, with each cell area being served by a base station, e.g. a Radio Base Station (RBS), sometimes referred to as Base Station (BS) for short, which in some networks is also referred to as "node B" or enhanced node B (which in Long Term Evolution (LTE) may be abbreviated as "eNodeB" or "eNB"). A cell is a geographical area in which radio coverage is provided by a radio base station apparatus on the base station side. The base stations communicate over the air interface operating on radio frequencies with UEs within range of the base stations.

In some versions of the RAN, several BSs are typically connected (e.g., by landlines or microwave) to a Radio Network Controller (RNC). A radio network controller (also sometimes referred to as a Base Station Controller (BSC)) oversees and coordinates various activities of the multiple BSs connected thereto. The RNC is typically connected to one or more core networks. The core network typically includes a Mobile Switching Center (MSC) that provides circuit-switched services and a Serving GPRS Support Node (SGSN) that provides packet-switched type services.

The Universal Mobile Telecommunications System (UMTS) is a third generation mobile communication system that has evolved from the global system for mobile communications (GSM) and is intended to provide improved mobile communication services based on Wideband Code Division Multiple Access (WCDMA) access technology. UTRAN (abbreviation for UMTS terrestrial radio access network) is a collective term for the enodebs and RNCs that make up the UMTS radio access network. Therefore, UTRAN is essentially a radio access network using WCDMA of user equipment units.

The third generation partnership project (3 GPP) has set forth additional evolutions of UTRAN and GSM based radio access network technologies. In this regard, evolved universal terrestrial radio access network (E-UTRAN) specifications are ongoing within the 3GPP. Evolved universal terrestrial radio access network (E-UTRAN) includes Long Term Evolution (LTE) and System Architecture Evolution (SAE).

Fig. 1 is a simplified block diagram of a Long Term Evolution (LTE) RAN 100. The LTE RAN 100 is a variant of the 3GPP RAN in which the radio base station node (eNodeB) is directly connected to the core network 130 instead of the RNC node. In general, the functions of an RNC node are performed by a radio base station node (sometimes simply referred to as a base station) in LTE. Each radio base station node (eNodeB 122-1, 122-2, … 122-M in FIG. 1) communicates with UEs (e.g., UEs 110-1, 110-2, 110-3, … 110-L within their respective communication serving cells). As is well known to those skilled in the art, radio base station nodes (enodebs) may communicate with each other over an X2 interface and with the core network 130 over an S1 interface.

The LTE standard is based on a multi-carrier based radio access scheme such as Orthogonal Frequency Division Multiplexing (OFDM) in the downlink and Discrete Fourier Transform (DFT) -spread OFDM in the uplink. OFDM technology distributes data over a large number of carriers spaced at precise frequencies. This spacing provides "orthogonality" in this technique, which avoids making the modulator aware of frequencies other than itself. The benefits of OFDM are high spectral efficiency, Radio Frequency (RF) interference resilience, and less multipath distortion. The basic LTE downlink physical resource may thus be seen as a time-frequency grid as illustrated in fig. 2A, where each resource element corresponds to one OFDM subcarrier during one OFDM symbol interval. In more detail, the LTE downlink physical resource of fig. 2A shows subcarriers with a spacing of Δ f =15kHz and a close-up of one OFDM symbol containing a cyclic prefix.

As shown by the LTE time domain structure of fig. 2B, in the time domain, LTE downlink transmissions are organized into 10 ms radio frames, each radio frame being of 10 lengths T_Sub-frameEqual-sized sub-frame composition of =1 ms.

Furthermore, resource allocation in LTE is typically described using resource blocks, where a resource block corresponds to one slot (0.5 ms) in the time domain (i.e., two slots per subframe) and 12 contiguous subcarriers in the frequency domain. Resource blocks are numbered in the frequency domain, starting from zero at one end of the system bandwidth. Downlink transmissions are dynamically scheduled, i.e. the BS transmits control information in each subframe, indicating to which (mobile) terminals and on which resource blocks data is transmitted during the current downlink subframe. This control signaling is typically transmitted in the first 1, 2, 3 or 4 OFDM symbols in each subframe. A downlink system (downlink subframe) having 3 OFDM symbols as a control region is illustrated in fig. 3.

Next, a Physical Uplink Control Channel (PUCCH) is described. As implied by the name, the PUCCH carries uplink control information, e.g., hybrid ARQ (hybrid automatic repeat request), Channel Quality Indicator (CQI), ACK/NACK, etc. LTE uses hybrid ARQ (hybrid automatic repeat request), where after receiving downlink data in a subframe, a terminal (e.g., user equipment) attempts to decode it and reports to the BS whether the decoding was successful (ACK) or failed (NACK). In case of unsuccessful decoding attempt, the BS may retransmit the erroneous data.

Uplink control signaling from the terminal to the base station may include: a hybrid ARQ acknowledgement for the received downlink data; terminal reports related to downlink channel conditions, used as assistance for downlink scheduling (also referred to as Channel Quality Indicator (CQI)); and/or a scheduling request indicating that the mobile terminal requires uplink resources for uplink data transmission.

If no uplink resources are assigned to the mobile terminal for data transmission, L1/L2 (layer 2 and/or layer 2) control information (channel state reports, hybrid ARQ acknowledgements, and scheduling requests) is transmitted in uplink resources (resource blocks) specifically assigned for uplink L1/L2 control information on the Physical Uplink Control Channel (PUCCH).

Different PUCCH formats are used for different information, e.g., PUCCH format 1a/1b for hybrid ARQ feedback, PUCCH format 2/2a/2b for reporting channel conditions, and PUCCH format 1 for scheduling requests.

Next, a Physical Uplink Shared Channel (PUSCH) is described. The scheduler allocates resources for the PUSCH on a subframe basis. To transmit data in the uplink, a mobile terminal (e.g., the aforementioned UE) must be assigned uplink resources for data transmission on a physical uplink shared channel. PUSCH resource assignments are shown in fig. 4, where resources assigned to two different users of one subframe are illustrated. The middle SC symbol in each slot is used to transmit reference symbols. If the mobile terminal has been assigned uplink resources for data transmission and at the same time the instance has control information to transmit, it will transmit control information and data on the PUSCH.

In the following, the concept of carrier aggregation is explained. LTE release 8 has recently been standardized to support bandwidths up to 20 MHz, e.g. including the subcarriers described above. However, to meet IMT-advanced requirements, 3GPP has initiated work on LTE release 10. A key part of LTE release 10 is to support bandwidths in excess of 20 MHz and ensure downward compatibility with LTE release 8. This should also include spectrum compatibility and mean that LTE release 10 carriers wider than 20 MHz should be implemented as multiple LTE carriers to LTE release 8 terminals. Each such carrier may be referred to as a Component Carrier (CC). In particular, for early LTE release 10 deployments, it is expected that there will be a smaller number of terminals that can implement LTE release 10 than many LTE legacy terminals. Therefore, it may be necessary to ensure efficient use of wide carriers also for legacy terminals, i.e. it is possible to implement carriers in which legacy terminals may be scheduled in all parts of the wideband LTE release 10 carrier. A straightforward way to achieve this would be to utilize Carrier Aggregation (CA). CA means that LTE release 10 terminals can receive multiple CCs (component carriers), where the CCs have, or at least are likely to have, the same structure as the release 8 carriers. CA is illustrated in fig. 5 as having an aggregated bandwidth of 100 MHz implemented by 5 component carriers.

The number of aggregated CCs and the bandwidth of individual CCs may be different for uplink and downlink. The symmetric configuration relates to a case where the number of CCs in the downlink and uplink is the same, whereas the asymmetric configuration relates to a case where the number of CCs is different. It is important to note that the number of CCs configured in a cell may be different from the number of CCs seen or used by a terminal. For example, a terminal may support more downlink CCs than uplink CCs, even though the cell is configured with the same number of uplink and downlink CCs.

Next, the uplink power control of the above-described PUSCH and PUCCH is explained. Uplink power control is used on both PUSCH and PUCCH. The aim is to ensure that the mobile terminal transmits with a sufficiently high but not too high power (since the latter would increase the interference to other users in the network). In both cases, a parameterized open loop combined with a closed loop mechanism is used. Generally, the open loop portion is used to set an operating point around which the closed loop component operates. Different parameters (target and local compensation factors) are used for the user plane and the control plane. For more details, please refer to segment 5.1.1.1 (PUSCH power control) and segment 5.1.2.1 (PUCCH power control) of the 3GPP TS 36.213 physical layer process, e.g., version 9.3.0 http:// www.3gpp.org/ftp/Specs/html-info/36213.htm of 2010-10-03.

To control the UE Uplink (UL) power, the eNB will use TPC (transmit power control) commands, which will command the UE to change its transmit power in an accumulated or absolute manner. In LTE release 10, UL power control is managed per component carrier. Since PUSCH and PUCCH power control is separated in release 8/9. In LTE release 10, PUCCH power control will only be applied to the Primary Component Carrier (PCC), since it is the only UL CC configured to carry PUCCH.

Since the TPC command does not have any ACK/NACK, the eNB cannot determine that the UE received the command, and since the UE may decode the PDCCH (physical downlink control channel) erroneously and think it received the TPC command, counting the used TPC command cannot be used to estimate the reliable current output power from the UE. Furthermore, the UE also autonomously compensates its power level (based on path loss estimation), and this adjustment is unknown to the eNB. For both reasons, the eNB needs to receive PHR (power headroom report) periodically in order to make adequate scheduling decisions and control the UE UL power.

Hereinafter, the power headroom report is explained. In LTE release 8, the base station may configure the UE to send power headroom reports periodically or when the change in path loss exceeds some configurable threshold. The power headroom report indicates how much transmit power the UE has left for subframe I, i.e. the difference between the nominal UE maximum transmit power and the estimated required power. The reported values are in the range of 40 to-23 dB, where negative values indicate that the UE does not have sufficient power to transmit.

The eNB uses the reported Power Headroom (PH) as input to the scheduler. Based on the available power headroom, the scheduler will decide a suitable number of PRBs (physical resource blocks) and good MCS (modulation and coding scheme) and suitable transmit power adjustment (TPC commands). In carrier aggregation, the eNB would make such an evaluation for each ULCC since the power is controlled per CC according to the RAN1 decision.

Since we have UL power control per CC and separately for PUSCH and PUCCH, this will also be reflected in the power headroom report. For release 10, there will be two types of PH reports:

● type 1 power headroom report — calculated as: p _ cmax, c minus PUSCH power (P _ cmax, c-P _ PUSCH)

● type 2 power headroom report — calculated as: p _ cmax, c minus PUCCH power minus PUSCH power (P _ cmax, c-P _ PUCCH-P _ PUSCH)

The secondary component carriers will always report type 1PHR since they are not configured for PUCCH. The primary component carrier may report type 1 and type 2 PHR. Type 1 and type 2PHR must be reported in the same subframe.

Applying the release 8 framework of power headroom reporting to carrier aggregation would mean sending the PHR for a particular component carrier on that component carrier itself. Further, if the terminal has PUSCH resources granted on this CC, the PHR may be transmitted only on the component carrier.

In RAN2 (radio access network 2), it is proposed to extend this framework so that a PHR for one component carrier can be transmitted on another component carrier. This enables fast path loss changes to be reported on one component carrier as long as the terminal has PUSCH resources granted on any configured UL component carrier. More specifically, more than one on any component carrierdl-PathlossChangeA path loss change in dB triggers transmission of the PHR on any (same or another) component carrier where the terminal has granted PUSCH resources.

In addition to PHR, each CC will have a Pcmax, c report to report the configured transmit power of the UE, which is designated Pcmax, c in 3GPP 36.213.

The Pcmax, c report may be included in the same MAC (medium access control) control element as the PH reported for the same CC, or it may be included in a different MAC control element. Some details are specified in R1-105796 (3GPP contact declaration), but the exact format and rules have not been defined.

In release 10, the power headroom will be reported to all configured and activated CCs. This means that in a TTI (transmission time interval), in which power headroom is reported, some CCs reporting a PH may not have a valid UL (uplink) grant. They will then use the reference format PUSCH and/or PUCCH to report the so-called virtual/reference format PH/PHR. These reference formats are described in R1-105820 (3GPP contact declaration). This is useful since they may be scheduled and transmitted in the future. In other words, for so-called virtual transmission, a CC is activated but not transmitted, but may nevertheless be scheduled for future transmission.

After configuration, each CC is assigned a cell index, which is unique to all CCs configured for a particular UE. The SIB2 (system information block 2) linking UL and DL is associated with the same cell index. The cell index may have a value of 0-7. A primary cell (PCell) is always assigned a value of 0.

Reporting of one or more PHs related to one or more CCs may be accomplished using a PH MAC control element, however, the format thereof is not defined. In particular, in order to report the power headroom and transmit power information (e.g., Pcmax, c), additional overhead may be generated, resulting in a waste of resources.

It is desirable to provide a carrier (e.g. a control element) that allows for efficient reporting of power information and methods, user equipment, base stations, systems and computer programs that allow for efficient reporting or handling of transmit power information (e.g. Pcmax, c).

Additional details of the Transmission technology (MEDIATEK) entitled "Release 10 PHR (Further details for Rel-10 PHR)", 3GPP DRAFT; r2-105444_ DISC MAC PHR, 3GPP, Mobile COMPENCE CENTER; f-06921 SOPHIA-ANTIPOLIS CEDEX; FRANCE, Vol. RAN WG2, No. Xi' an; the document 2010-10-05, XP050453602 is a conference paper of the working group and is proposed to have a new LCID. It also discusses a new Power Headroom Report (PHR) with fixed or variable length by taking into account several variations shown in the paper. It is also proposed to include an explicit mapping (e.g., bitmap) to clearly indicate the Component Carriers (CCs) that include the PHR. It also mentions that the bitmap may include MAC CEs or subheaders.

Zhongxing (ZTE) corporation entitled "PHR MAC CE DESIGN", 3GPP DRAFT; r2-105341 PHR MAC CE DESIGN, 3GPP, Mobile COMPENCE CENTER; f-06921 SOPHIA-ANTIPOLIS CEDEX; FRANCE, Vol. RAN WG2, No. Xi' an; the document 2010-10-03, XP050452396 is a conference paper of the working group, which just describes the power headroom MAC CE design for adapting carrier aggregation PHR reporting, and uses a 1-byte bitmap to identify the power headroom. No information on the identifier or the transmission power is provided.

Document TSG RAN WG 1: "LS response on per UE PHR-UE PHR", 3GPP DRAFT; R2-106046_ R1-105796, 3GPP, Mobile COMPENCE CENTER; f-06921 SOPHIA-ANTIPOLIS CEDEX; FRANCE, Vol. RAN WG2, No. Jacksonville, USA; 2010-11-01, XP050491881 is also a conference paper of the working group, held from 11 months, 15-19 days 2010.

Disclosure of Invention

Such a control element, method, user equipment, base station, system and computer program are defined in the independent claims. Advantageous embodiments are described in the dependent claims.

In one embodiment, a power headroom control element is provided for communicating power information from a User Equipment (UE) to a Base Station (BS) in a Radio Access Network (RAN). The power headroom control element is configured to include a power headroom field containing power headroom information. The power headroom field has a predetermined number of bits (particularly at predetermined positions) in the power headroom control element. The power headroom control element is further configured to include an indicator field associated with the power headroom field. The indicator field is used to indicate whether a transmission power field having a predetermined number of bits is present in the power headroom control element. Accordingly, the presence of the transmit power field can be easily and efficiently reported without incurring large overhead.

In one embodiment, a method of communicating power information containing a power headroom from a UE to a BS in a RAN is provided. The method comprises the following steps: determining whether a transmission power field containing information on a transmission power of an uplink serving cell associated with a power headroom is to be transmitted together with the power headroom, and if it is determined that the transmission power field is to be transmitted, adding the power headroom field having the power headroom value and the transmission power field for transmission to a power headroom control element, and setting an indicator to a specific value to indicate that the transmission power field is contained. Thus, a simple method of communicating power information through a power headroom control element is provided.

In one embodiment, a method performed by a BS in a RAN is provided for processing power information received from a UE, the power information comprising a power headroom report for a received power headroom control element. The method comprises the following steps: determining whether a value in an indicator field associated with a power headroom field of the received power headroom control element is set to a specific value indicating that a transmission power field associated with the power headroom field is included in the power headroom control element, and reading the transmission power field if the value of the indicator field is set to the specific value. Accordingly, the power information contained in the power headroom control element can be easily and quickly evaluated.

In one embodiment, a method of communicating a power headroom control element containing a power headroom from a UE to a BS in a RAN is provided, wherein the power headroom control element is constructed in the manner described above. Therefore, power information can be efficiently transferred.

In one embodiment, a User Equipment (UE) for delivering power information including a power headroom to a BS in a RAN is provided. The UE includes a processor configured to determine whether a transmission power field containing information on a transmission power of an uplink serving cell associated with a power headroom is to be transmitted together with the power headroom, and if it is determined to be transmitted, control adding the power headroom field having a power headroom value and the transmission power field for transmission to a power headroom control element, and set an indicator to a specific value to indicate that the transmission power field is contained. Accordingly, a UE capable of efficiently transferring power information by controlling the structure and information content of a power headroom control element is provided.

In one embodiment, a base station in a RAN is provided that is configured to process power information received from a UE, the power information comprising a power headroom report for a received power headroom control element. The base station includes a processor configured to determine whether a value in an indicator field associated with a power headroom field of the received power headroom control element is set to a specific value indicating that a transmission power field associated with the power headroom field is included in the power headroom control element, and to read the transmission power field if the value is set to the specific value. Accordingly, power information received in the power headroom control element can be easily and quickly evaluated.

In another embodiment, a system for communicating power information is provided that includes the user equipment and the base station described above.

In another embodiment, a memory is provided that stores a power headroom control element constructed as described above. In another embodiment, a computer program is provided comprising instructions configured to cause a data processor to perform one of the above-described methods when executed on the data processor.

Further advantageous embodiments of the invention are disclosed in the dependent claims.

Drawings

Fig. 1 illustrates a block diagram of an LTE RAN as known to those skilled in the art.

Fig. 2A illustrates a structure of an LTE downlink physical resource.

Fig. 2B illustrates radio frames and subframes in the time domain in LTE.

Fig. 3 illustrates a downlink subframe used in LTE.

Fig. 4 illustrates PUSCH resource assignment.

Fig. 5 illustrates the concept of carrier aggregation.

Fig. 6 illustrates an example of a power headroom control element using a bitmap solution.

Fig. 7 illustrates an example of a power headroom control element using a ranking solution.

Fig. 8 illustrates an example of a power headroom control element containing two bitmaps.

Fig. 9 illustrates a power headroom control element according to an embodiment.

Fig. 10 illustrates an exemplary power headroom control element according to an embodiment.

Fig. 11 illustrates another exemplary power headroom control element using a bitmap according to an embodiment.

Fig. 12 illustrates another exemplary power headroom control element including a type 1 power headroom report according to an embodiment.

Fig. 13 illustrates exemplary power headroom control elements including type 2 and type 1 power headroom reports according to an embodiment.

Fig. 14A and 14B illustrate exemplary power headroom control elements when the power headroom field is not byte aligned according to an embodiment.

FIG. 15 illustrates a table illustrating different settings of indicator bits and their meaning.

Fig. 16 illustrates a flow diagram of a method of communicating power information, according to an embodiment.

Fig. 17 illustrates a more detailed method of communicating power information, according to an embodiment.

Fig. 18 illustrates a flow diagram of a method performed by a base station for processing received power information, according to an embodiment.

Fig. 19 illustrates a user equipment for communicating power information according to an embodiment.

Fig. 20 illustrates a system including a user terminal and a base station according to an embodiment.

Detailed Description

Further embodiments of the invention are described with reference to the figures. It is noted that the following description contains examples only and should not be construed as limiting the invention.

In the following, similar or identical reference numbers indicate similar or identical elements, units or operations.

Fig. 6 to 14 illustrate a power headroom control element, which constitutes, for example, the above-described power headroom MAC control element. Those skilled in the art understand that the control elements described herein are data elements used to carry information, particularly in an LTE RAN. Hereinafter, the format of the power headroom control element will be described in more detail.

The power headroom control element is used, for example, to carry power information from the UE to the BS in the RAN (e.g., LTE RAN), and is described in 3GPP TS 36.321 (e.g., release 9.3.0 of month 6 2010). For example, the power headroom control element 600 of fig. 6 is configured to include an 8-bit bitmap 610 to indicate which component carriers or corresponding uplink serving cells are reporting power headroom reports, a reporting power headroom report is a report containing information about power headroom, wherein the information about power headroom (e.g., a specific value) may be contained in a power headroom field. In particular, bit fields 630 and 640 each contain an R bit (i.e., a reserved bit) that is typically set to zero. The PH field 620 is a power headroom field indicating a power headroom level. The length of this field is typically 6 bits. In particular, the power headroom field 620 reports a type 2PHR in the power headroom control element of fig. 6 and the lower PH field reports a type 1 PHR. Whether a type 2PHR exists depends on the configuration and does not need to be indicated. As can be seen from fig. 6, the PH field is located at a predetermined position in the power headroom control element (PH CE), i.e., the PH field is located at bit positions 3 to 8 within one octet (octet) of the power headroom control element, which octet contains the power headroom of one specific CC.

Each bit in the 8-bit bitmap 610 corresponds to a cell index from 0 to 7, e.g., the cell index of the uplink serving cell. In the example of fig. 6, the PH fields contained in the power headroom MAC CE are ordered in ascending order based on cell index, i.e., cell indexes 0 to 7 are assigned from left to right and corresponding PH fields are assigned from top to bottom. It is clear that the cell indices can also be assigned from right to left, i.e. in descending order when reading from left to right. In this example, the type 2PHR is included in the first PH field, but it may be included in the last PH field.

In more detail, a bit value of 1 in the bitmap corresponding to a cell index of 0 (leftmost in the bitmap) indicates that a primary cell (PCell) corresponding to a primary component carrier reports a type 2PHR in a PH (type 2) field 620 and reports a type 1PHR in a PH (type 1) field below the field 620. A second bit value of 1 at cell index 1 in the bitmap indicates that the first secondary cell corresponding to the first secondary component carrier also reports type 1PHR and a bit value of 1 at a fourth position (cell index 3) in the bitmap indicates that the third secondary cell also reports type 1PHR in the last PH field of the power headroom control element in fig. 6. Bit value 0 for the remaining cell index indicates that no CC is configured to it or configured with a CC but is currently deactivated. It will be described with respect to fig. 14A and 14B that the position of the PH field with respect to the 8-bit structure in fig. 6 can be variously selected. However, the PH field should always be located at the same predetermined position in the control element, for example at a predetermined position of the octets described above (e.g. bit positions 3 to 8), so that its information can be easily found at the same position.

This solution of using an 8-bit bitmap in the example of fig. 6 to communicate power information is referred to herein as a bitmap solution.

A different solution, namely a ranking solution, is explained with respect to fig. 7. As can be seen in fig. 7, the power headroom control element is illustrated as not comprising an 8-bit bitmap. Since power headroom reports are reported for configured and activated CCs, it is assumed that both the eNodeB and the UE know which CCs are activated at a given point in time. If a type 2PHR exists or not depends on the configuration and need not be indicated. Therefore, a bitmap is not necessarily required and the type 1PHR is sorted in descending or ascending order based on the cell index and the type 2 power headroom report is included in the first or last (if any). The example in fig. 7 shows a power headroom control element having a type 2PHR in the first PH field and a type 1PHR of a cell with an increased cell index.

Although the power information of the power headroom report may already be used by the eNodeB as input to the scheduler, it is further desirable to report the transmission power of the uplink serving cell or the respective component carrier (e.g., Pcmax, c) together with the power headroom report in order to facilitate the eNodeB (i.e., the base station). In 3GPP TS 36.213, one example of the per component carrier transmission power for the calculation of PH is referred to as Pcmax, c. Pcmax, c is also referred to from 3GPP TS 36.101 as the configured transmit power per component carrier. In this standard document, the UE is allowed to set its configured maximum output power Pcmax. ", c" is a notation indicating that this is CC specific Pcmax.

If Pcmax, c is reported for all CCs reporting PHR, then all Pcmax, c reports may follow the same order or corresponding Pcmax, c reports may be included after each PHR as a PHR according to any of the above solutions (bitmap solution or sorted solution). Furthermore, they may also be included in their own power headroom MAC control element and in the same order as the power headroom reports.

However, if only a subset of CCs report Pcmax, c, then for example the above solution would not work since the CCs reporting the power headroom report may not necessarily use the so-called reference or virtual PUSCH or PUCCH format, since the eNodeB would not be able to know if there are which CCs have Pcmax, c reports.

This problem may be solved by including another 8-bit bitmap in the power headroom control element (as shown in fig. 8) to indicate which Pcmax, c reports are present. The first five lines of the bitmap containing the power headroom control element of fig. 8 are the same as the power headroom control element of fig. 6 described above.

Furthermore, as seen in fig. 8, an additional octet is provided with a bitmap indicating the cell and the component carrier reporting the transmit power (e.g., Pcmax, c) accordingly. In the example of fig. 8, the primary component carrier reports Pcmax, c for type 2 power headroom reporting and Pcmax, c for type 1 power headroom reporting for the primary component carrier and Pcmax, c for type 1 power headroom reporting for a cell with a cell index of 3 (i.e., a third secondary cell). Thus, three Pcmax, c reports are reported with the power headroom control element of fig. 8. Since the carrier component report for cell index 1 is a power headroom report instead of a Pcmax, c report, this indicates that this component carrier has no valid uplink grant in the transmission time interval in which the power headroom report is reported and thus the so-called virtual/reference format power headroom report is reported using the reference PUSCH format. However, by using additional bitmaps, additional overhead is incurred in the control elements, and therefore a more economical solution is desired.

Instead of using an additional bitmap to provide a link between the cell index and the transmit power (e.g., Pcmax, c), the association between the power headroom report and the CC may be reused to associate Pcmax, c with PHR instead of using an additional identifier to associate it with the CC, according to some embodiments. Thus, the transmit power (e.g., Pcmax, c) may be reported more efficiently by associating the transmit power with the power headroom report only when it needs to be reported. This will be described in more detail below.

According to some embodiments, one or two of the R bits in an octet (i.e., 8-bit field) containing a PH (i.e., power headroom information) may be used to indicate whether this PH, and thus also the CC associated with this PH, has an associated transmit power report (e.g., Pcmax, cbort).

For example, fig. 9 illustrates a power headroom control element for communicating power information from a UE to a BS (e.g., eNodeB) that is configured to include a power headroom field (i.e., a PH field 910). The PH field contains power headroom information, i.e., information on a power headroom to be reported, and has a predetermined number of bits at a predetermined position in the power headroom control element. As indicated above, the PH field has a length of 6 bits and is located at bit positions 3 to 8 in the octet of the power headroom control element. In fig. 9, one of the R bits, in particular the second R bit at bit position 2 of the octet, is used as an indicator field 920. In fig. 9, the indicator field has one bit, but it is also feasible that the indicator field can be extended to 2 bits, for example by including an R bit at bit position 1 of the octet. The indicator field 920 is associated with the PH field 910. In other words, since the indicator field 920 and the PH field 910 are in the same octet, there is a clear association between the fields.

The indicator field is used to indicate whether a transmission power field having a predetermined number of bits is present in the power headroom control element. The power headroom control element of fig. 9 illustrates a transmit power field, here specifically a Pcmax, c field 930, which contains transmit power information (e.g., Pcmax, c report). Similar to the PH field 910, the transmit power field 930 may also have a predetermined number of bits at predetermined positions, e.g., 6 bits at bit positions 3 to 8 in an octet of the power headroom control element. The two R bits of the octet in which the transmit power field is located may remain unused.

The control element of fig. 9 includes an indicator field, a PH field, and a transmit power field located below the PH field, wherein the indicator field is located in the same octet as the PH field and is used to indicate the presence of the transmit power field. In particular, the bits of the power headroom field and the associated indicator field form part of the octets of the power headroom control element and the bits of the transmit power field form part of the octets of the power headroom control element. Thus, the transmit power field 930 is similar to the PH field 910 associated with the same cell index as the PH field 910, since the indicator field 920 is located in the same octet as the PH field and indicates the presence of the following (subsequent) transmit power field.

As explained above, the PH field 910 contains power headroom information and is associated with an uplink serving cell. If the above-described ordering solution is used, a bitmap for indicating associated cell indexes is not necessary to associate the PH field 910, which is the first PH field in the power headroom control element, with the primary cell having a cell index of 0. If the bitmap solution described above is used, a bitmap may be included before the PH field, indicating which cell index the PH field is associated with. In the example of fig. 9, a possible bitmap may be a bit value of 1 for cell index 0 and a bit value of 0 for the other cell indices 1 through 7.

In the previous discussion, a bit value of 1 in the bitmap indicates that a PHR exists in a cell corresponding to a cell index. However, it is clear that the same indication can be achieved if a bit value of 0 is defined as a bit value where the corresponding cell has the PHR and a bit value of 1 indicates that the corresponding cell does not have the power headroom report.

As can be seen in fig. 9 to 14, the PH field precedes the associated transmit power field in the power headroom control element. In particular, the octet comprising the PH field precedes the octet comprising the associated transmit power field. Therefore, the power headroom control element first carries the power headroom information in the PH field and then the transmit power information in the transmit power field. In detail, the transmission power field contains information (e.g., Pcmax, c) on the transmission power of the uplink serving cell or component carrier, which is associated with the previous power headroom information.

As explained above, at least one bit in the indicator field may indicate that there is a Pcmax, c report, i.e. a report on the transmit power of the uplink serving cell or associated component carrier. In addition, the indicator field may also indicate whether the PH is a so-called virtual or reference format.

In detail, if a so-called virtual/reference format power headroom report is to be sent for a cell with a specific cell index, it is not necessary for the component carriers to report the transmission power (e.g., Pcmax, c). In this case, the CC is active but not transmitted, and a so-called virtual transmission is used for the calculation of the PH. Thus, an indicator (i.e. a bit value set in an indicator field, e.g. a value indicating the presence of a so-called dummy or reference format power headroom report) may also be used to indicate whether or not to transmit a Pcmax, c report. For example, if a virtual/reference format power headroom report is used and indicated, there will be no Pcmax, c report (transmit power report) for this CC reported in this TTI. Furthermore, in other embodiments, one of the R bits of the MAC subheader may be used to indicate that all power headroom reports reported in a particular TTI (at least for type 1 reports) are associated with the same Pcmax, c report.

In accordance with the above, a transmit power report (e.g., Pcmax, c report) may be identified by reusing existing bits rather than adding an additional unnecessary identifier (e.g., an additional bitmap). In the bitmap solution and ordering solution described above, and also for other possible solutions not mentioned here, the eNodeB will know which power headroom report is associated with which CC. Taking advantage of this fact, it is possible to associate a transmit power report with a specific PHR (i.e., a PHR already associated with a CC), and thus a transmit power report is also associated with the CC, rather than adding another identifier (e.g., the additional bitmap described above). In other words, it should be appreciated that an association (Pcmax, c- > PHR- > CC) between transmit power, power headroom and CC is possible and that one of the R bits available in each octet containing the PH field (since the PH field itself has only 6 bits) may be used to indicate the PHR and thus also whether the CC associated with this PHR has an associated transmit power (e.g., Pcmax, c) also reported in this TTI.

Based on this information, the eNodeB will know how many transmit power reports to expect and for which CCs. The transmit power report (e.g., Pcmax, c report) may be contained directly after each associated PH field (particularly after each octet containing the PH field), or all transmit power reports may be contained after all PH fields in cell index order. It is also possible that all transmit power reports are contained in their own control element but that the R bits of the octets of the PHs associated with the same CC can still be used to indicate the presence of each transmit power report.

Furthermore, as described above, if it is agreed to always report Pcmax, c in addition to CCs that report power headroom using virtual/reference PUSCH and/or PUCCH formats, the eNodeB may also use the information provided to the eNodeB via this R bit on whether to provide Pcmax, c reports to know whether a particular power headroom is transmitted based on virtual/reference formats (when PH is reported without Pcmax, c) or based on actual transmissions (when PH is reported with Pcmax, c).

Hereinafter, power headroom control elements of different formats using the above described ordering solution, bitmap solution, and combination of the ordering and bitmap solutions are described with respect to fig. 10 to 14.

Fig. 10 illustrates an embodiment in which the same power headroom control element after the PH field is added with the associated Pcmax, c report, indicating the presence of the Pcmax, c report using one of the R bits in the octet of the PH field. In this embodiment, octets with PH fields are stacked according to cell index, where the PH associated with the primary cell (PCell, cell index = 0) is at the top containing type 2PH and type 1PH, and the following secondary cells (scells) start with the SCell of the lowest cell index.

In detail, type 2 and type 1PH of the primary cell are shown in the first two entries, and a type 1 power headroom report of the first secondary cell and a type 1 power headroom report of the second secondary cell are shown from top to bottom. The rightmost (alternatively leftmost) R bit in the octet that also contains power headroom information is used to indicate whether the Pcmax, c report is also contained for this PH (i.e., the CC associated with this power headroom report). In this embodiment, setting the bit to "1" indicates that Pcmax, c is expected to be reported, but likewise, in another embodiment a value of "0" can indicate this. In other words, the meaning of a bit value of "1" may change to the meaning of a bit value of "0" and vice versa.

The Pcmax, c reports are then layered after the power headroom report starting with the Pcmax, c report associated with the PHR associated with the lowest cell index CC, and then the others follow in consecutive order. In the example of fig. 10, the Pcmax, c report 1020 is associated with a type 1 power headroom report 1010 associated with the PH field of the PCell, and the second Pcmax, c report 1040 is associated with a type 1 power headroom report 1030 associated with the PH field of the second SCell.

The size of the field carrying the Pcmax, c report may range from 5 to 8 bits and is not as important as the R bits used only in the octets of the power headroom report. In addition, if the indicator field is constructed of only one R bit, the PH field may be extended even to 7 bits.

Similar to the power headroom control element of fig. 9, the power headroom control element of fig. 10 also has a format in which the bits of the power headroom field and the associated indicator field form part of or the entire octet of the power headroom control element (the PH field includes 6 bits and the indicator field is 1 or 2 bits), and/or the bits of the transmit power field (e.g., containing Pcmax, cbrok or other transmit power report) form part of the octet of the same power headroom control element.

In the following, another example of a power headroom control element is described with respect to fig. 11, where a similar format as discussed with respect to fig. 9 and 10 is used, however the bitmap solution described above is used.

In detail, the power headroom control element of fig. 11 includes a bitmap to indicate which uplink serving cell reports power headroom information as part of this power headroom control element.

The sequence of the PH field in fig. 11 is the same as previously described with respect to fig. 6 and uses the same cell index. In fig. 11, a bit value of "1" in the bitmap indicates a power headroom report including a primary cell, a first secondary cell, and a third secondary cell. In addition, as previously described with respect to fig. 10, some of the R bits are used as indicators with indicator fields and specific values. In detail, the rightmost R bit of the octet containing the PH field is used to indicate for which power headroom reports a transmit power report (e.g., Pcmax, c report) is contained. In particular, it is indicated in fig. 11 that for type 1 power headroom reports associated with cell index 0 and type 1 power headroom reports associated with cell index 3, including transmission power reports, which are shown in fig. 11 by Pcmax, c, wherein the first Pcmax, c report at the top is associated with the type 1PH field belonging to cell index 0 and thus with the primary cell, and the second Pcmax, c report is associated with the type 1 power headroom report belonging to cell index 3 and thus with the third SCell.

Fig. 12 and 13 illustrate a power headroom control element similar to that of fig. 11, which also includes a bitmap. After the MAC subheader of the PH MAC control element and after the bitmap, octets containing the type 2PH field in fig. 13 and the type 1PH field in fig. 12 are provided at the top, followed by octets containing the associated transmit power if reported in a non-virtual format. Octets are then followed in ascending order based on the cell index, where the octets with the PH field are followed by octets with associated transmit power fields for each active serving cell indicated by bits in the bitmap. As mentioned above, a bit value of "1" in the bit field of the bitmap indicates a PH field of a cell reporting a cell index corresponding to the bit field. If the bit value is "0", the PH field is not reported. In fig. 12 and 13, only 7 bits in the bitmap are used to indicate a cell index and thus whether a report is associated with a primary cell or a secondary cell, and the 8 th bit of the bitmap is a reserved bit (R bit). As already mentioned above, the cell indices are provided in increasing order from left to right in fig. 6, 8, 11, 12 and 13, but equally the cell indices may also be increased from right to left, which only depends on predefined rules.

With respect to the power headroom control element of fig. 11, where all power headroom fields are first contained in the data element from top to bottom and then contain the associated transmit power field, the transmit power field is always contained directly in the next octet after the corresponding PH field in fig. 12 and 13.

In more detail, in the example shown in fig. 12, in which the power headroom control element contains only the type 1PHR when the type 2PHR is not reported, a specific value "1" in the indicator field of the indicator in the first octet indicates that the transmission power field containing information on the transmission power (e.g., Pcmax, c) of the uplink serving cell is contained in the next octet. After reporting Pcmax, c, the next octet again includes a PH field, e.g., the PH field shown in fig. 12, which contains a type 1PHR of the first secondary cell with a cell index of 1. Since this octet again comprises an indicator field having a bit value of "1", the subsequent octets will again comprise a transmit power field containing, for example, a Pcmax, c report.

The power headroom control element of fig. 13 is substantially the same as the power headroom control element in fig. 12, but type 2PHR and associated transmit power are also reported for the primary cell in the two topmost octets. Here, Pcmax, c1 is associated with type 2PHR, Pcmax, c2 is associated with a first type 1PHR, and Pcmax, c3 is associated with a second type 1 PHR.

In the examples shown in fig. 12 and 13, the indicator of the value "1" indicates that all power headroom reports are non-virtual PHR. However, as mentioned above, if a virtual PHR is to be sent and Pcmax, c is not to be reported, since the eNodeB may calculate this Pcmax, c value anyway, a bit value in the indicator field may indicate that the power headroom is virtual (e.g., bit value "0") and it would not be necessary to signal Pcmax, c for the power headroom based on the reference format or virtual format. Thus, the power headroom control element enables sending virtual power headroom reports for component carriers that have no transmissions granted by the scheduler of the eNodeB.

As shown in fig. 9 to 13, for both type 1 and type 2 power headroom reports, the indicator field with bit value =1 indicates the presence of the associated transmit power field (here the so-called Pcmax, c field), and bit value =0 indicates the omission of the associated transmit power field. Alternatively, as described above, an indicator field having a bit value =0 may indicate the presence of an associated transmit power field, and a bit value =1 may indicate that the associated transmit power field (Pmax, c field) is omitted.

In another embodiment, explained with respect to fig. 14a and 14b, the power headroom report is not byte aligned. For example, there may be an indicator bit in the indicator field after (or before) each power headroom report to indicate whether Pcmax, c is transmitted. If so, it may be transmitted next or next to the end or in a separate control element.

In the examples described above, the R bit used as an indicator bit may also be used to indicate whether the power headroom report is based on the virtual/reference PUSCH and/or PUCCH format. If it is desired not to report Pcmax, c associated with power headroom reporting using the reference format of PUSCH, PUCCH, or both, the eNodeB may use this indicator to also derive information whether Pcmax, c reporting should be expected in this TTI.

In the following, some characteristics of the PCell PHR (including type 1 and type 2) are described. The number of Pcmax, c fields contained by the Pcell may vary depending on whether no, one or two PHR are based on the virtual/reference format and also whether type 1 and type 2 are based on different Pcmax, c. The table in fig. 15 lists the combination of indicator R bits for type 1 and type 2PHR octets and whether Pcmax, c is included (in this table "0" indicates the reference format, but of course the opposite case is also possible).

For example, as may be taken from the first row of the table, if the value of the bit of the indicator (first bit) contained in the same octet as the type 1PHR is "0" and the value of the bit of the indicator (second bit) contained in the same octet as the type 2PHR is "0", neither the type 1 nor the type 2PHR is based on non-virtual (real) transmission, i.e. neither PUSCH nor PUCCH transmission occurs on the PCell in this TTI. There is no need to report Pcmax, c.

As indicated in the second row of fig. 15, if the first bit value is "0" and the second bit value is "1", the type 1PHR is based on the virtual/reference PUSCH format and the type 2PHR is based on the real (non-virtual) PUCCH and the virtual/reference PUSCH format. Pcmax, c of type 2PHR, which is the cause of PUCCH transmission, is transmitted.

If the first bit value is "1" and the second bit value is "0", the type 1PHR is based on the real PUSCH format and the type 2PHR is based on the virtual/reference PUCCH and the real PUSCH format. Pcmax, c of type 1PHR, which is the cause of PUSCH transmission, is reported, and Pcmax, c associated with type 2PHR may be reported only when needed.

If the first bit value is "1" and the second bit value is "1", both type 1 and type 2 PHRs are based on a true transmission. Pcmax, c of type 1 (PUSCH only) and type 2 (PUSCH and PUCCH) need to be reported. Depending on the UE implementation/standardization, one or potentially two Pcmax, c need to be reported for the same CC.

In additional embodiments, all Pcmax, c values associated with PHR/CC in this TTI (at least for type 1 PHR) may have the same value. Then, one R bit in the MAC subheader (or any other indicator in the MAC subheader or the MAC control element itself) may be used to indicate that all PHR reported in this PHR MAC control element should be associated with the same Pcmax, c report. The Pcmax, c report may be included in the same MAC control element or in a separate MAC control element. These additional embodiments may be combined with the embodiments discussed in detail above to use an indicator to indicate which PHR should not have a Pcmax, c associated with it in a particular TTI and report.

According to the above embodiments, it is possible not to report the transmit power (e.g., Pcmax, c) of all CCs for which the PH is reported, i.e., only some Pcmax, c are reported. This may be useful in the case when the PH uses a virtual format and the eNodeB already has knowledge of the information contained in the Pcmax, c report, and therefore does not need to receive it. Furthermore, in the embodiments described with respect to fig. 9-14, no additional octets are needed to identify the transmit power report (e.g., Pcmax, c report) and existing reserved bits are available for its identification. Even considering the non-byte aligned PHRMAC control element solution as shown in fig. 14a and 14b, only one extra bit is needed per reported PH.

Further, if the transmit power (e.g., Pcmax, c) is always to be reported in addition to the CCs that use the virtual/reference PUSCH and/or PUCCH formats to report PHs, the eNodeB may also use the information on the transmit power report (e.g., Pcmax, c report) provided to the eNodeB via this R bit to know whether a particular PH is transmitted based on the virtual/reference format or based on the actual transmission. Since embodiments may also work in other similar ways (if Pcmax, c reports are indicated according to one embodiment and their presence depends on the non-virtual/non-reference format PH), both types of information may be obtained from the same indicator bit.

In the following, a flow chart illustrating operations according to some embodiments is described.

The flowchart shown in fig. 16 describes an operation of transferring power information containing a power headroom report from a UE to a BS (e.g., eNodeB).

In a first step 1610, it is determined whether a transmit power field associated with a PH is to be transmitted. In more detail, it is determined whether a transmission power field containing information on a transmission power (e.g., power Pcmax, c) of an associated uplink serving cell associated with the PH is to be transmitted together with the PH.

If it is determined in step 1610 in fig. 16 that the transmission power field is not to be transmitted, the process flow ends. However, if it is determined in step 1610 that a transmit power field (e.g., a field containing a Pcmax, c report) is to be sent, e.g., if the associated power headroom report is based on actual transmission, the PH field and the transmit power field are added for transmission to the power headroom control element in step 1640. Accordingly, a PH control element including a PH field and a transmission power field similar to the PH control element in fig. 9 is provided.

In step 1660, an indicator is set to a specific value to indicate that the octet containing the transmit power field is contained in the PH MAC control element. In more detail, the indicator includes an indicator field having a bit contained therein having a specific value. For example, if the specific value of the bit is 1, it indicates that the transmit power is reported in the transmit power field, i.e. Pcmax, c report is included.

In one embodiment, the determining step 1610 is performed if it was previously determined that the PHR was triggered. In other words, if it is decided to report the PH for a specific serving cell, it is necessary to check whether the PH is in a virtual or real format and check whether a transmission power field is included in the PH control element based thereon. Thus, whether the transmit power field is to be sent is based on whether the cell has an uplink grant that is valid for transmission (i.e., non-virtual or actual transmission) for this TTI.

If it is determined not to transmit the transmission power field, for example, if the associated PH is a virtual format, the PH (i.e., virtual PH) is added to the power headroom control element and the indicator is set to another specific value to indicate that the transmission power field is not included. If the specific value of step 1660 previously described is taken to be "1", the other specific values are taken to be "0".

Similarly, if it is determined that the PH is to be prepared based on the virtual transmission (i.e., in case of the virtual PH), the indicator is set to other specific values to indicate that the associated transmission power field is not included in the PHR.

The flow chart of fig. 17 describes the steps explained above in a more detailed order, which shows an example of how the indicator is set for the Scell. For Pcell, it is possible to trigger two PHR, each associated with its own Pcmax, c report (which may be similarly illustrated).

In step 1720, at least one PHR has been triggered and is to be prepared for transmission in this Transmission Time Interval (TTI).

The following steps will then be performed for each SCell. In step 1740, it is checked whether the serving Scell has a triggered PHR. If this SCell has a triggered PHR, the flow proceeds to step 1760, where it checks if an associated Pcmax, c report is to be sent with this PHR.

If a Pcmax, c report is not to be sent (e.g., because the associated PH is a virtual format), then flow proceeds to step 1790, where the PH is added to the PH MAC control element and the indicator is set to "0".

If it is determined in step 1760 that a Pcmax, c report associated with this PH is to be sent, e.g., if the PH is based on a true transfer, the flow proceeds to step 1780, where the PH (in particular the PH field) is added to the PH MAC control element and the indicator is set to "1". Further, Pcmax, c reports are added for transmission in this TTI.

According to the flowcharts of fig. 16 and 17, if the specific value of the indicator in the indicator field is "1", the presence of the Pcmax, c field associated with the PH is indicated, and if the value of the indicator in the indicator field is another specific value (here, "0"), the omission of the Pcmax, c field is indicated. This determination is independent of the type of PH and thus may be performed for type 1 and type 2 PHs. Alternatively, a particular value of "0" may indicate Pcmax, for which reporting is expected, and another particular value of "1" may indicate Pcmax, for which reporting is not expected.

For example, the operations described with respect to fig. 16 and 17 may be performed in a User Terminal (UT) (e.g., a User Equipment (UE)), and in particular by equipment (e.g., a processor as will be described in more detail with respect to fig. 19) that is specifically adapted or configured to perform these steps. After the UE forwards power information including one or more PHs and one or more transmission power reports associated with the PHs, a power headroom control element carrying the power information is received at the base station. The base station receives the power information and processes the power information as described in more detail with respect to fig. 18.

In step 1820, once the BS receives a PH control element including power information from the UE, the BS determines whether a value in an indicator field of the received PH control element is set to a specific value indicating that a transmission power field associated with the PH field is included in the PH control element. For example, if the specific value is "1" (as discussed with respect to fig. 17), this indicates that the transmit power field, and thus the transmit power information (e.g., Pcmax, c report), is included in the power headroom control element.

Then, if the value of the indicator field is set to a specific value of "1", the BS reads out the transmission power field in step 1840, and thus the BS acquires the transmission power information.

If it is determined that the value of the indicator field is set to another specific value (e.g., "0"), the BS understands that the specific PH is prepared based on the virtual transmission and does not contain the associated transmission power field. Therefore, subsequent octets in the power headroom control element will not be interpreted as a transmit power field. Therefore, it is possible to provide the BS with clear instructions on how to interpret the information sent in the power headroom control element. As a result, it is possible to efficiently report and handle the transmit power information (e.g., Pcmax, c).

In the above-described embodiments, a power headroom control element is communicated (i.e., sent) from the UE to the BS in the RAN, wherein this power headroom control element contains one or more PH fields and zero or more Pcmax, c fields, and is constructed as described above.

In the examples and embodiments described above, it has been shown that it is possible to re-use the association between PH and CC to associate Pcmax, c with PH instead of using an additional identifier to associate it with CC.

This is achieved, for example, by using one of the R bits in the octets of the PH containing the power headroom control element to indicate whether this PH (and thus also the CC associated with this PH) has an associated Pcmax, c report.

As shown in fig. 6 through 14, since the primary cell may have a PH of one or two reports that may potentially be based on different Pcmax, c values, the presence of one or two Pcmax, c reports may be decided based on a combination of R bits for indication.

In addition, it has been shown that it is possible to use an existing indicator, e.g. an indicator indicating that a so-called virtual or reference format PH is sent, to know whether to transmit a Pcmax, c report. In this example, if the virtual/reference format PH is indicated, then Pcmax, c reporting for this CC will not be reported in this TTI. In addition, one of the R bits of the MAC subheader may be used to indicate that all PHR reported in a particular TTI (e.g., at least for type 1 reports) are associated with the same Pcmax, c report.

As a result, using the indicator described above, it is possible to find that PH is calculated using a virtual format and Pcmax, c is not transmitted, which can be easily indicated using one specific bit position indicating whether Pcmax, c is present in the power headroom control element.

As discussed above, a User Terminal (UT) (referred to above as a user equipment or UE by way of example) may communicate with a BS (referred to above as an eNodeB by way of example) using an Uplink (UL) for wireless radio transmissions from the UT to the BS and using a Downlink (DL) for wireless radio transmissions from the BS to the UT, as shown in fig. 20 below.

As shown in fig. 19 and 20, user terminal UT (e.g., user device 1900) may include processor 1920 of fig. 19 or processor UTPR of fig. 20. The processor may be coupled to the transceiver 1960 in fig. 19 or UTXCVR in fig. 20. In addition, the processor is also preferably connected to a memory 1940.

For example, the processor 1920 of the user equipment 1900 is configured to determine whether a transmission power field (e.g., Pcmax, c) containing information on a transmission power of an uplink serving cell associated with a power headroom is to be reported with the power headroom. If it is determined that the transmit power field is to be sent, the processor is further configured to, for example, control adding the power headroom field and the transmit power field for transmission to the power headroom control element and setting an indicator to a specific value to indicate that the transmit power field is included. The details regarding the PH field of the PHR, the transmission power field containing transmission power information, and the indicator field have been described above and may also be applied herein.

The memory 1940 may be a memory storing one of the power headroom control elements described above.

The transceiver 1960 or a transceiver UTXCVR like the map 20 is adapted to transmit and receive communications, e.g. including the control elements described above.

Hereinafter, the system shown in fig. 20 is described in more detail. The system of fig. 20 includes a User Terminal (UT) and a Base Station (BS). The processor UTPR of the UT may be configured to prepare a power headroom report and/or Pcmax, c report communication for transmission as discussed above. Similarly, the BS may include a processor BSPR coupled to the transceiver BSTXCVR, and the processor BSPR may be configured to process the received power headroom report and/or Pcmax, c report communications as discussed above.

In more detail, the BS may be configured to process the received power information including a power headroom report of the received power headroom control element. The base station processor may be configured to determine whether a value in an indicator field of the received power headroom control element is set to a specific value indicating that a transmit power field associated with a specific power headroom is included in the power headroom control element, and to read the transmit power field if the value is set to the specific value. Details of this operation have been described above.

In summary, according to the above case, it is possible not to report the transmission power (e.g., Pcmax, c) of all CCs for which the PH is reported. This may be useful in the case when the virtual format PH is reported and the BS (e.g. eNodeB) already has knowledge of the information contained in the associated Pcmax, c report, and thus will not need to receive it.

In addition, according to embodiments of the present invention, any additional octets identifying the Pcmax, c report need not be transmitted and existing reserved bits may be used instead. Even if a non-byte aligned PH MAC CE solution is applied, only one extra bit is needed per PH.

Further, if Pcmax, c is to be reported in addition to CCs that use virtual/reference PUSCH and/or PUCCH formats to report PHs, the eNodeB may also use the information provided to the eNodeB via this R bit on whether to provide Pcmax, c reporting to know whether a particular PH is transmitted based on virtual/reference formats or based on actual transmissions. Since embodiments of the present invention will also work in other similar ways (if Pcmax, c reports are indicated according to one embodiment and their presence depends on the non-virtual/non-reference format PH), there is a benefit from obtaining both types of information from the same indicator bit.

Although primarily discussed in terms of communications according to the LTE standard by way of example, communications may be provided according to other wireless communication standards, such as Advanced Mobile Phone Service (AMPS), ANSI-136, global standard for mobile communications (GSM), General Packet Radio Service (GPRS), enhanced data rates for GSM evolution (EDGE), DCS, PDC, PCS, Code Division Multiple Access (CDMA), wideband CDMA, CDMA2000, and/or Universal Mobile Telecommunications System (UMTS) frequency bands. Furthermore, a user terminal/device according to embodiments of the present invention may be, for example, any wireless ("mobile") communication terminal ("wireless terminal" or "terminal") configured to perform cellular communication (e.g., cellular voice and/or data communication) using multiple component carriers.

Embodiments have been described more fully herein with reference to the accompanying drawings, in which embodiments are shown. This invention may, however, be embodied in alternate forms and should not be construed as limited to the embodiments set forth herein.

Accordingly, while the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that there is no intention to limit the invention to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. Like numbers refer to like elements throughout the description of the figures.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," "including," "has," "having," or any variation thereof, when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Further, when an element is referred to as being "responsive" or "connected" to another element or variations thereof, it can be directly responsive or connected to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly responsive" or "directly connected" to another element or variations thereof, there are no intervening elements present. As used herein, the term "and/or" encompasses any and all combinations of one or more of the associated listed items and may be abbreviated as "/".

It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the teachings of the present disclosure. Further, although some of the figures include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

The entities according to the different embodiments of the present invention, including the devices and stations as well as the apparatuses, devices and systems (which include processors and/or memories) may comprise or store a computer program comprising instructions to cause the computer program when executing the steps and operations according to the embodiments of the present invention, i.e. to cause the data processing apparatus to perform the operations. In particular, embodiments of the present invention also relate to a computer program for performing operations according to embodiments of the present invention, and to any computer-readable medium storing a computer program for performing the above-described method.

Similar to a specifically configured processor, different specific units may be used to perform the functions of the device and the station or system described above. Further, the functionality may be distributed over different software or hardware components or devices for enabling the desired functionality to occur. A number of different units for providing the desired functionality may also be gathered. The functions may also be implemented in hardware, software, Field Programmable Gate Arrays (FPGA), Application Specific Integrated Circuits (ASIC), firmware, or the like.

Example embodiments are described herein with reference to block diagrams and/or flowchart illustrations of computer-implemented methods, apparatus (systems and/or devices), and/or computer program products. It will be understood that blocks of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions which are executed by one or more computer circuits. These computer program instructions may be provided to a processor circuit or a general purpose computer circuit, a special purpose computer circuit, and/or other programmable data processing circuits to produce a machine, such that the instructions, which execute via the processor of the computer and/or other programmable data processing apparatus, transform and control transistors, values stored in memory locations, and other hardware components within such circuits to implement the functions/acts specified in the block diagrams and/or flowchart block or blocks, and thereby produce an apparatus (functionality) and/or structure for implementing the functions/acts specified in the block diagrams and/or flowchart block or blocks.

These computer program instructions may also be stored in a computer-readable medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instructions which implement the function/act specified in the block diagrams and/or flowchart block or blocks.

A tangible, non-transitory computer-readable medium may include an electronic, magnetic, optical, electromagnetic, or semiconductor data storage system, device, or apparatus. More specific examples of the computer readable medium would include the following: a portable computer diskette, a Random Access Memory (RAM) circuit, a read-only memory (ROM) circuit, an erasable programmable read-only memory (EPROM or flash memory) circuit, a portable compact disc read-only memory (CDROM), and a portable digital video disc read-only memory (DVD/BlueRay).

The computer program instructions may also be loaded onto a computer and/or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer and/or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the block diagrams and/or flowchart block or blocks.

Accordingly, the present invention may be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc.) that runs on a processor (e.g., a digital signal processor), which may be collectively referred to as "circuitry," "module," or variants thereof.

It should also be noted that, in some alternative implementations, the functions/acts noted in the blocks may occur out of the order noted in the flowcharts. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Furthermore, the functionality of a given block of the flowchart and/or block diagrams may be separated into multiple blocks and/or the functionality of two or more blocks of the flowchart and/or block diagrams may be at least partially integrated. Finally, other blocks may be added/inserted between the illustrated blocks.

Many different embodiments have been disclosed herein in connection with the above description and illustrations. It will be understood that verbatim descriptions and illustrations of each combination and subcombination of the embodiments can be overly duplicative and confusing. Accordingly, the specification (including drawings) is to be construed as constituting a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and is to support claims to any such combination or subcombination.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In the specification, embodiments of the invention have been disclosed and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

Other implementations of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only. To this end, it is to be understood that inventive aspects lie in less than all features of a single foregoing disclosed implementation or configuration. With the true scope and spirit of the invention being indicated by the following claims.

Claims (17)

1. A method of setting a power headroom control element communicated from a user equipment, UE, to a base station to indicate inclusion of a transmit power field, the method comprising the steps of:

determining whether a transmit power field (930) containing information about a transmit power of an uplink serving cell associated with a power headroom is to be transmitted with the power headroom; and

if it is determined that the transmission power field (930) is to be transmitted, adding a power headroom field (910) with the power headroom and the transmission power field (930) for transmission to a power headroom control element and setting an indicator to a specific value to indicate that the transmission power field is included.

2. The method of claim 1, wherein the determining step is performed if it is determined that a power headroom report is triggered.

3. The method according to claim 1 or 2, wherein the determination whether a transmission power field is to be sent is based on whether the cell has uplink transmission.

4. The method according to any of claims 1 to 2, wherein if it is determined that the transmit power field is not to be sent, adding the power headroom field to a power headroom control element and setting the indicator to another specific value to indicate that the transmit power field is not included.

5. The method according to any of claims 1 to 2, wherein if it is determined that the power headroom is to be prepared based on a dummy transmission, setting the indicator to another specific value indicates that the associated transmit power field is not included in the power headroom control element.

6. A method performed by a base station in a radio access network, RAN, for processing power information received from a user equipment, UE, comprising a power headroom report of a received power headroom control element, the method comprising the steps of:

receiving a power headroom control element from a User Equipment (UE), the power headroom control element containing power headroom information in a power headroom field in the power headroom control element;

determining whether a value in an indicator field (920) associated with a power headroom field (910) of the received power headroom control element is set to a specific value indicating that a transmit power field (930) associated with the power headroom field (910) is contained in the power headroom control element; and

reading the transmit power field (930) if the value of the indicator field (920) is set to the specific value.

7. The method of claim 6, wherein if it is determined that the value of the indicator field (920) is set to another specific value, the power headroom report is prepared based on a dummy transmission and does not contain an associated transmission power field.

8. A user equipment for setting a power headroom control element communicated to a base station to indicate inclusion of a transmit power field, the user equipment comprising a processor (1960) configured to:

determining whether a transmission power field containing information on a transmission power of an uplink serving cell associated with the power headroom is to be transmitted together with the power headroom; and

controlling adding a power headroom field with the power headroom and the transmit power field for transmission to a power headroom control element and setting an indicator to a specific value to indicate inclusion of the transmit power field if it is determined to send the transmit power field.

9. A base station in a radio access network, RAN, configured to process power information received from a user equipment, UE, including a received power headroom report of a power headroom control element, the base station comprising a processor configured to:

receiving a power headroom control element from a User Equipment (UE), the power headroom control element containing power headroom information in a power headroom field in the power headroom control element;

determining whether a value in an indicator field (920) associated with a power headroom field of the received power headroom control element is set to a specific value indicating that a transmit power field associated with the power headroom field is included in the power headroom control element; and

reading the transmit power field if the value is set to the specific value.

10. A system for communicating power information, the system comprising a user equipment according to claim 8 and a base station according to claim 9.

11. An apparatus for setting a power headroom control element communicated from a user equipment, UE, to a base station to indicate inclusion of a transmit power field, comprising:

means for determining whether a transmit power field (930) containing information about a transmit power of an uplink serving cell associated with a power headroom is to be transmitted with the power headroom; and

means for adding a power headroom field (910) having the power headroom and the transmit power field (930) for transmission to a power headroom control element and setting an indicator to a specific value to indicate inclusion of the transmit power field if it is determined to send the transmit power field (930).

12. The apparatus of claim 11, wherein the determination is performed if it is determined that a power headroom report is triggered.

13. The apparatus according to claim 11 or 12, wherein the determination whether a transmit power field is to be sent is based on whether the cell has uplink transmission.

14. The apparatus according to any of claims 11 to 12, further comprising means for adding the power headroom field to a power headroom control element and setting the indicator to another specific value to indicate that the transmit power field is not included if it is determined that the transmit power field is not to be sent.

15. The apparatus according to any of claims 11 to 12, further comprising means for setting the indicator to another specific value to indicate that an associated transmit power field is not included in the power headroom control element if it is determined that the power headroom is to be prepared based on a virtual transmission.

16. An arrangement in a base station in a radio access network, RAN, for handling power information received from a user equipment, UE, comprising a received power headroom report of a power headroom control element, the arrangement comprising:

means for receiving a power headroom control element from a user equipment, UE, the power headroom control element containing power headroom information in a power headroom field in the power headroom control element;

means for determining whether a value in an indicator field (920) associated with a power headroom field (910) of the received power headroom control element is set to a specific value indicating that a transmit power field (930) associated with the power headroom field (910) is contained in the power headroom control element; and

means for reading the transmit power field (930) if the value of the indicator field (920) is set to the specific value.

17. The apparatus of claim 16, wherein if it is determined that the value of the indicator field (920) is set to another specific value, the power headroom report is prepared based on a dummy transmission and does not contain an associated transmission power field.