WO2017171895A1

WO2017171895A1 - Link adaptation for low complexity device to device (d2d) communication

Info

Publication number: WO2017171895A1
Application number: PCT/US2016/039360
Authority: WO
Inventors: Sergey PANTELEEV; Alexey Khoryaev; Sergey Sosnin; Mikhail Shilov
Original assignee: Intel Corp
Current assignee: Intel Corp
Priority date: 2016-04-01
Filing date: 2016-06-24
Publication date: 2017-10-05
Anticipated expiration: 2018-10-01
Also published as: CN108702244A; CN108702244B; HK1258367A1

Abstract

An apparatus for use in a user equipment (UE), the apparatus includes circuitry to set a sidelink transmission modulation and coding scheme (MCS) based on a physical sidelink shared channel reference signal received quality (S-RSRQ), or set a sidelink transmission power level based on the sidelink pathloss. The S-RSRQ may be measured or calculated based on a sidelink received signal strength indication (S-RSSI), a sidelink interference signal strength indication (S-ISSI), and a sidelink reference signal received power (SL-RSRP), while pathloss between the UE and another UE may be obtained based on the SL-referenceSignalPower, and the SL-RSRP or a sidelink discovery reference signal received (SD-RSRP).

Description

LINK ADAPTATION FOR LOW COMPLEXITY DEVICE TO DEVICE (D2D)

COMMUNICATION

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority from U.S. Provisional Patent Application No. 62/317,088, filed April 1, 2016, and entitled "LINK ADAPTATION TECHNIQUES FOR LOW COMPLEXITY LTE D2D COMMUNICATION", the entire disclosure of which is hereby incorporated by reference.

TECHNICAL FIELD

Embodiments generally may relate to the field of wireless communications.

BACKGROUND

LTE (long-term evolution) networks may provide for device-to-device (D2D) communication.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements. Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings.

Figure 1 illustrates a schematic high-level example of a network that includes user equipments (UEs) and an evolved NodeB (eNB), in accordance with various embodiments.

Figure 2 illustrates example components of a remote UE or a relay UE according to various embodiments.

Figure 3 illustrates a UE in accordance with various embodiments.

Figure 4 illustrates a link adaption process for D2D communication between a remote UE and a relay UE, in accordance with various embodiments.

Figure 5 illustrates another link adaption process for D2D communication between a remote UE and a relay UE, in accordance with various embodiments.

Figure 6 illustrates another link adaption process for D2D communication between a remote UE and a relay UE, in accordance with various embodiments.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawings. The same reference numbers may be used in different drawings to identify the same or similar elements. In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular structures, architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the various aspects of the claimed embodiments. However, it will be apparent to those skilled in the art having the benefit of the present disclosure that the various aspects of the embodiments and claims may be practiced in other examples that depart from these specific details. In certain instances, descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present embodiments with unnecessary detail.

For the purposes of the present disclosure, the phrases "A/B," "A or B," and "A and/or B" mean (A), (B), or (A and B). For the purposes of the present disclosure, the phrases "A, B, or C" and "A, B, and/or C" mean (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

The description may use the phrases "in an embodiment," or "in embodiments," which may each refer to one or more of the same or different embodiments. Furthermore, the terms "comprising," "including," "having," and the like, as used with respect to embodiments of the present disclosure, are synonymous.

As discussed herein, the term "module" may be used to refer to one or more physical or logical components or elements of a system. In some embodiments a module may be a distinct circuit, while in other embodiments a module may include a plurality of circuits.

Device-to-Device (D2D) communication refers to a radio technology that enables devices, e.g., UEs, to communicate directly with each other, that is without routing the data paths through a network infrastructure. Proximity-based services can be provided when UEs are close to each other. Terms D2D, sidelink (SL), and Proximity Services (ProSe) are used interchangeably herein.

In 3GPP Release (Rel.) 12, an initial framework of D2D communication for LTE

(LTE D2D) is introduced targeting public safety use cases and consumer use cases. The framework includes D2D discovery and D2D communication. D2D discovery is supported for consumer use cases, while D2D communication, supported for both consumer and public safety use cases, is mainly designed for out-of-coverage, partial coverage, and long-range voice communication in public safety use cases. In Rel. 13, a functionality of UE-to-network (NW) relaying using layer 3 (L3) forwarding is introduced. Additionally, out-of-coverage discovery is introduced to aid UE-to-NW relay discovery and group discovery. Accordingly, LTE D2D as discussed in Rel. 12/13 does not address link adaptation issues since LTE D2D is designed mainly for broadcasting used in public safety applications. In legacy systems, the broadcasting transmissions do not take into consideration of channel quality, but use a pessimistic modulation and coding scheme (MCS) and transmission power level. On the other hand, D2D one-to-one communication may be useful for new devices, e.g., wearable computing devices and internet of things (IoT) devices. The pessimistic MCS and transmission power levels used in legacy systems may lead to low spectrum and energy efficiency for D2D communication with wearable devices and IoT devices.

Example embodiments herein provide enhancements to D2D communications, and in particular, enhancements to D2D communications for wearable computing devices, machine-type communication (MTC) devices, and/or IoT devices. More specifically, example embodiments provide enhancements to D2D communications with link adaptation by determining MCS and transmission power levels based on channel quality between UEs.

Figure 1 depicts a high-level example of network 1000. Network 1000 may include two or more UEs, such as UE 120 and UE 130. Either of UE 120 and UE 130 may be a D2D transmitter, or a D2D receiver. Network 1000 may further include an eNB, e.g., eNB 1 15. In embodiments, eNB 115 may be configured to transmit or receive one or more signals to or from UEs 120 and 130, for example, via a cellular communication interface Uu as indicated by the solid lines in Figure 1. In some embodiments, network 1000 may be included in a wide area network (WAN), and transmissions between eNB 115 and UEs 120 or 130 may use resources of the WAN. Additionally, UEs 120 and 130 may be configured to transmit or receive one or more signals to or from one another via D2D communication interface PC5, as indicated by the dashed line. For example, UEs 120 and 130 may exchange control information via one or more Scheduling Assignment (SA) transmissions, and/or data transmissions as explained herein. In embodiments, UE 120 or UE 130 may perform mode switching between PC5 interface and Uu interface to communicate in either D2D mode or cellular mode.

In embodiments, UE 130 may be a wearable/IoT UE accessing a network using a relayed D2D connection with UE 120, where UE 120 may be a non-IoT, e.g., a smartphone, a tablet computing device, etc., acting as a D2D or ProSe relay node. The connection between wearable/IoT UE 130 and relay UE 120 may be a "sidelink." Wearable/IoT UE 130 may have the capability for direct communication with the eNB; however, this capability may be used in exceptional cases and/or for acquisition of control information, e.g., attachment to an access network such as the Evolved Universal Terrestrial Access Network (E-UTRAN).

In embodiments, regardless of possible cellular capabilities of the device, UE 130 may be one of the following D2D capability categories:

Table 1

In D2D communication, e.g., communication over the PC5 interface, UEs may share the uplink resources with the devices attached to the network. In embodiments, some physical channels may be introduced: the physical sidelink control channel (PSCCH) carrying the control information, and the physical sidelink shared channel (PSSCH) carrying the data. The control and data may be placed in the PSCCH and the PSSCH, while the discovery information may be carried in the physical sidelink discovery channel (PSDCH). In addition, Physical Sidelink Broadcast Channel (PSBCH) may be used for broadcasting system sidelink information to UEs.

For legacy systems such as LTE D2D, there may not be any link adaptation mechanism. Instead, the transmissions for broadcasting do not take channel quality into consideration. Example embodiments herein may enable link adaptations for unicast D2D communication, which may benefit D2D communications for wearable computing devices and IoT devices.

Example embodiments herein may provide enhancements to D2D communications with link adaptation by determining MCS and transmission power levels based on channel quality. In embodiments, channel quality and conditions may be measured in medium time-scale and the measurements of channel conditions may be used for pathloss estimation, transmission power level adjustments, and MCS selection. In the medium time-scale link adaptation, the MCS selection may be performed for a sidelink control information (SCI) period.

The following terms are used herein:

• Remote UE - a wearable computing device (e.g., smartwatch or health sensor) or IoT/MTC device (e.g., stationary smart meter) that may communicate with a network via another UE using a D2D air-interface. Remote UEs may communicate over a Uu air-interface, which is the cellular interface between the UE and the e B. In embodiments, a remote UE may have lower capabilities and may benefit from low-power and low-cost operations.

• Relay UE - a UE capable of relaying traffic to/from another UE from/to network using D2D air-interface. Examples of relay UEs may include smartphones, tablet computing devices, laptops, desktop personal computers, and/or any other like computing device. A relay UE may be a D2D capable UE and/or ProSe enabled UE such that the relay UE may be capable of supporting of D2D/ProSe direct discovery, communication, and/or act as a D2D/ProSe UE-to-NW relay.

• Relay discovery - a procedure of discovering and selecting a relay UE by a remote UE. Relay discovery may also be referred to as "ProSe Direct Discovery." The procedure may be performed before transmitting control and data on sidelink.

• Master UE and Slave UE - a Master UE may be a UE that may control operations on a direct link with another UE. A Slave UE may be a UE that may be controlled by another UE, e.g., a Master UE, for resource allocation, scheduling, measurements, etc. In embodiments, when a Master UE controls resource allocation for a Slave UE, the Master UE may perform the measurements and determine the MCS and other transmission parameters according to the measurement of channel conditions. In some other embodiments, the MCS used by the Master UE for transmission may be reported or provided by the Slave UE.

There may be various measurements about the channel conditions. For example, Sidelink Discovery Reference Signal Received Power (SD-RSRP) and Sidelink Reference Signal Received Power (S-RSRP) measurements may be defined over PSDCH and PSBCH, respectively, which may be used for layer 3 (L3) relay selection and for synchronizations. S-RSRP may be a linear average over the power contributions of the resource elements that carry demodulation reference signals associated with PSBCH within the central 6 physical resource blocks (PRBs) of the applicable subframes. S-RSRP may be used for synchronization procedure for partial coverage and out-of-coverage UEs. S-RSRP may not be a suitable measurement used for other purposes.

The SD-RSRP measurements over PSDCH may be used to set transmission power level and coarse level MCS in an interference-free environment. However, the SD-RSRP does not take into account interference level during data transmission in PSCCH and PSSCH. In fact, PSDCH, PSCCH, and PSSCH may generally use different transmission power levels and MCS, and the SD-RSRP measurements may not be sufficient for proper determination of the transmission power levels and MCS used in PSCCH and PSSCH.

In embodiments, two additional measurements may be performed to support enhanced medium time scale link adaptation for transmission power level control and MCS selection purposes.

• Sidelink pathloss (PLs) - PLs may be a sidelink pathloss estimate between two UEs, e.g., a relay UE and a terminal UE, or a remote UE. PLs can be measured on any side of a link between two UEs because of reciprocity principle, hence simplifying measurement procedures for low-power wearable devices. PL_S may enable UE-UE sidelink-specific power control. In embodiments, PLs may be measured on one side of the link and reported to another side of the link. Alternatively, PLs may be measured on both sides.

• Sidelink Reference Signal Received Quality (S-RSRQ) - The S-RSRQ may be related to large scale signal-to-interference-plus-noise ratio (LS-SINR), and may be used for medium time scale link adaptation to set MCS. The S-RSRQ may also be used for mode switching between Uu and PC5 operation.

Sidelink Pathloss

PL_S may be calculated using the equation PL_S = SL-referenceSignalPower - SL- RSRP. In embodiments, SL-RSRP and SL-referenceSignalPower may be calculated or obtained in different ways.

In embodiments, SL-RSRP may be calculated as SD-RSRP, which may be a linear average over the power contributions of the resource elements that carry demodulation reference signals associated with PSDCH for which a cyclic redundancy check (CRC) has been validated. In embodiments, Energy per Resource Element (EPRE) of Demodulation Reference Signal (DMRS) used for PSDCH transmission may be signaled from upper layers before measuring SD-RSRP.

In embodiments, a new RSRP measured over PSCCH or PSSCH may be performed as SL-RSRP. In embodiments, an initial transmission of PSSCH and PSCCH may be performed with a transmission power as the cellular power PL_C (e B-UE pathloss). After obtaining the sidelink pathloss PL_S, the transmission power for sidelink may be changed. In embodiments, the EPRE of DMRS for PSCCH/PSSCH may also be signaled from upper layers before measuring pathloss.

Similarly, in embodiments, SL-referenceSignalPower may be calculated in different ways. In embodiments, a predefined power control parameter for transmission of reference signals may be used as SL-referenceSignalPower . However, it may be difficult to determine a predefined power control parameter in most cases.

In embodiments, SL-referenceSignalPower may be signaled in a payload of some channel, e.g., in the channel over which the measurement may be performed. For example, SL-referenceSignalPower may be placed into a PSDCH payload. For such cases, PLs may be quickly calculated by measuring the SD-RSRP and extracting the corresponding SL-referenceSignalPower from PSDCH payload. In embodiments, SD- RSRP may be measured after CRC passes. In embodiments, signal range (-60...50) dBm may be used for the sidelink, which can be represented by at most 7 bits when if 1 dBm granularity may be considered.

In embodiments, SL-referenceSignalPower may be obtained in a different way. For example, SL-RSRP instead of SL-referenceSignalPower may be received by signaling from an upper layer, afterwards, the Master UE may calculate SL-referenceSignalPower using the signaled SL-RSRP and the knowledge of transmission power according to the equation PLs = SL-referenceSignalPower - SL-RSRP. In embodiments, a Master UE may transmit reference signals for measurement of SL-RSRP. Alternatively, in embodiments, a Slave UE may estimate SL-RSRP. In some embodiments, the Slave UE may signal the SL- RSRP to the Master UE. Similarly, the Master UE may signal the SL-RSRP to the Slave UE. The exact determination as which UE may signal the SL-RSRP may depend on the complexity and power consumption aspects of the application.

In embodiments, PLs may be measured for a ProSe group. There may be multiple sources of PSDCH, thus the values may be stored with respect to the corresponding source identity of the ProSe group. According to relay discovery procedure, the PSDCH transmission may precede the communication in UE-to-NW relaying, hence measuring pathloss on PSDCH may be useful for determining PLs.

S-RSRQ The S-RSRQ may be used for medium time scale link adaptation to set MCS. In addition, the MCS may be fine-tuned based on ACK/NACK feedbacks. In embodiments, channel characteristics measured over PSSCH, e.g., SL-RSRP, Sidelink Reference Signal Strength Indicator (S-RSSI), and Sidelink Interference Signal Strength Indication (S-ISSI) may be used to calculate S-RSRQ, where S-ISSI may be an interference plus noise component of the S-RSSI.

The main components to calculate S-RSRQ may be the following:

S-RSRQ = N- SL-RSRP /S-RSSI;

S-RSSI = NSL-RSRP + S-ISSI; LS-SINR = NSL-RSRP/S-ISSI; and

S-RSRQ = 1/ (1 + 1/LS-SINR).

• Nmay be the number of PRBs in the measurement bandwidth.

• SL-RSRP may be either measured over PSSCH or calculated using the pathloss equation, SL-RSRP = SL-referenceSignalPower - PLs , where PLs may be measured using a dedicated procedure, and the SL-referenceSignalPower may be received from an upper layer.

• S-RSSI may be a linear average of the total received power observed in certain OFDM symbols of measurement subframes, in the measurement bandwidth, over N number of resource blocks by the UE from all sources, including co-channel serving and non- serving cells, adjacent channel interference, thermal noise etc. In embodiments, S-

RSSI may be the sum of all the received signals including useful, interference and noise = N SL-RSRP + S-ISSI, where S-ISSI may be the interference signal strength indication comprised interference and noise powers measured in the bandwidth N.

• In embodiments, both SL-RSRP and S-RSSI may be measured over the same resource elements to obtain a consistent result.

In embodiments, S-RSRQ may be measured at both sides of a link between two UEs due to different interference at different sides. In embodiments, when a Master UE controls a Slave UE, S-RSRQ calculations for both sides may be performed by the Master UE.

In embodiments, various operation processes may be illustrated to show how S-

RSRQ may be obtained. There may be many more possible operations to obtain S-RSRQ which are not shown. Option 1 :

Master^Slave S-RSRQ

- The Master UE calculates PLs using SD-RSRP measured on PSDCH as described above.

- The Master UE calculates PSSCH SL-RSRP. The Master UE may calculate SL-RSRP by using power control parameters and the Slave UE's resource allocation size to determine SL-referenceSignalPower and PLs. In embodiments, the Master UE may measure SL-RSRP for the actual allocation.

- The Master UE measures S-RSSI/S-ISSI over PSSCH to determine S-RSRQ. Master→Slave S-RSRQ:

- The Slave UE calculates S-ISSI over PSSCH.

- The Slave UE reports S-ISSI to the Master UE.

- The Master UE using the power control parameters and pathloss estimates PSSCH SL- RSRP.

- The Master UE calculates S-RSSI using the reported S-ISSI and the calculated SL- RSRP.

- The Master UE calculates S-RSRQ. Option 2:

Master→Slave S-RSRQ: - The Slave UE calculates S-RSSI over PSSCH.

- The Slave UE reports S-RSSI to Master UE.

- The Master UE estimates PSSCH SL-RSRP based on the power control parameters and pathloss.

- The Master UE filters out the measurements from the Slave UE that do not contain its useful power. In this way, the Master UE may differentiate S-RSSI and S-ISSI.

- The Master UE calculates S-RSRQ. Power Control In embodiments, the control of transmission power level, which may also be referred to as power control or transmission power control (TPC), for UE-UE link may be determined based on PL_S. for PSCCH and PSSCH. For example, the following power control equations may be used in various embodiments for PSSCH. Same or similar equations may be used for PSCCH transmission power control. PLs measured on a UE- UE link may be used for setting transmission power if the resulting transmission power does not exceed the legacy setting using eNB-UE pathloss parameter.

For sidelink transmission mode 1 and PSSCH period /^', the UE transmission power Ppssch may be decided by the following:

if the TPC command field in configured sidelink grant for PSCCH period i is set to

0, Ppssch = PCMAX.PSSCH,

1, Ppssch = mm{PcMAx,psscH, lOlogio (M_PSSCH) + P₀_PSSCH, I+ a_PSscH,i*m {PL_c, PL_S + A_c-S/ ttpssccH,i ⁺ SPSSCH } }[ dBm].

For sidelink transmission mode 2, the UE transmission power P_psSch may be decided by the following:

Ppssch = mm{PcMAx,psscH, lOlogio (M_PSSCH) + P₀_PSSCH,2⁺ apsscH,2*m {PL_c, PL_S + A_c. apssccH,2 ⁺ &PSSCH,2 } }[ dBm].

Explanation of symbols in above equations may be as follows: PC_MA_X._PSSC_H may be the linear value of the UE total configured maximum output power, M_PSSCH may be the bandwidth of the PSSCH resource assignment expressed in number of resource blocks, P₀_PSSCH, U P₀_PSSCH,2, IPSSCH and a_PSscH,2 may be provided by higher layer parameters that may be associated with the corresponding PSSCH resource configuration, PL_S may be defined previously if parameter X or Y may be signaled and PL_S = co if parameter X or Y may not be signaled, PL_C has been described previously.

A higher layer signaling parameter X may allow UE-UE pathloss to be used for power control. A higher layer signaled parameter Acs (Y) regulates an offset between a transmission power calculated using eNB-UE pathloss and transmission power calculated using UE-UE pathloss. A transmission power adjustment command _PSscc_H,i _{, PSSCCH,2,} SpsscHi, and S_PSSC_H,2 may be applied if they are received from control signaling.

The pathloss measurement PL_S may be performed according to procedures described above. The pathloss may be either estimated by the transmitting UE or may be taken from higher layer signaling. The activation flag X and offset value Y may be signaled by e B or by a Master UE using higher layer signaling. In case of e B, the system information block (SIB) or dedicated radio resource control (RRC) may be used for signaling. In embodiments, for a Master UE, the parameters may be signaled using a control medium access control (MAC) protocol data unit (PDU) format as described further.

Power Control Parameters Configuration

In embodiments, a remote UE may have a Uu interface and may read system information blocks. Example embodiments may place the open loop power control (OLPC) parameters and new parameters of various embodiments in SIB 18. In some embodiment when a remote UE does not have capability to read SIB 18, the power control parameters may be provided by a relay UE (Master UE).

Measurement Request

In embodiments, a separate MAC control element (CE) may be introduced to request measurement reporting for current or the upcoming SCI period. The MAC CE may carry a measurement set ID and a measurement type. The measurement ID may correspond to one of the measurement sets configured in the dedicated D2D RRC message. The measurement type may trigger either MAC CE transmission with average measurements or D2D RRC message with extended measurements.

Measurement Report

In embodiments, average values may be provided using MAC CE mechanism due to the fixed size of the report. The MAC CE may carry a measurement set ID, a measurement type, a measurement value, and a counter (subframe or SCI period). In embodiments, 8 bits may be sufficient to report (-60...50) dBm with 0.5 dBm granularity.

Transmit Power Adjustment Commands

In embodiments, the TPC commands may also be carried by MAC CE in order to be multiplexed with usual data in PSSCH channel. In embodiments, the CE content may include power adjustment for PSCCH, and power adjustment for PSSCH.

D2D RRC Messages for Link Adaptation

In embodiments, RRC level signaling using various kinds of header formats for PC5 interface may be implemented to maintain the unicast D2D communication. The information that may be exchanged in some embodiments may be described herein.

Measurement Set Configuration

In embodiments, a dedicated D2D RRC message may carry configuration of subframe measurement sets/patterns. A pattern may be a bitmap or a vector of indexes to indicate subframes inside SCI period where a corresponding measurement may be performed. The pattern may be accompanied with pattern ID and measurement type (or types) which may be reported for current set/pattern.

Measurement Reporting

In embodiments, time-frequency selective measurements over different sets and patterns may be reported by a D2D RRC message when RRC mechanisms for D2D are available.

PSDCH changes

In embodiments, PLs may be calculated by PLs = SL-referenceSignalPower - SL- RSRP. In embodiments, SL-RSRP may be calculated as SD-RSRP, EPRE of DMRS used for PSDCH transmission may be signaled from upper layers before measuring SD-RSRP. There may be different options for PSDCH to carry the identified information for pathloss calculation using EPRE of DMRS.

In embodiments, a MAC PDU format for sidelink discovery channel (SL-DCH) may be introduced. In legacy systems, the transparent MAC mode may be used for SL- DCH transmission, i.e. the MAC service data unit (SDU) may be bypassed without modifications to the physical layer, only higher layer information may be carried in discovery messages. In this case, the described information may be multiplexed using a MAC CE sub-header and corresponding information into the discovery message.

In embodiments, RRC message may be carried by SL-DCH MAC SDU. The

MAC transparent mode may be reused in this case.

Embodiments described herein may be implemented into a system using any suitably configured hardware and/or software. Figure 2 illustrates, for one embodiment, example components of an electronic device 100. In embodiments, the electronic device 100 may be, implement, be incorporated into, or otherwise be a part of a MTC UE described herein. In some embodiments, the electronic device 100 may include application circuitry 102, baseband circuitry 104, Radio Frequency (RF) circuitry 106, front-end module (FEM) circuitry 108 and one or more antennas 110, coupled together at least as shown.

As used herein, the term "circuitry" may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and/or memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable hardware components that provide the described functionality. In some embodiments, the circuitry may be implemented in, or functions associated with the circuitry may be implemented by, one or more software or firmware modules. In some embodiments, circuitry may include logic, at least partially operable in hardware.

The application circuitry 102 may include one or more application processors. For example, the application circuitry 102 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled with and/or may include memory/storage and may be configured to execute instructions stored in the memory/storage to enable various applications and/or operating systems to run on the system.

The baseband circuitry 104 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 104 may include one or more baseband processors and/or control logic to process baseband signals received from a receive signal path of the RF circuitry 106 and to generate baseband signals for a transmit signal path of the RF circuitry 106. Baseband processing circuity 104 may interface with the application circuitry 102 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 106. For example, in some embodiments, the baseband circuitry 104 may include a second generation (2G) baseband processor 104a, third generation (3G) baseband processor 104b, fourth generation (4G) baseband processor 104c, and/or other baseband processor(s) 104d for other existing generations, generations in development or to be developed in the future (e.g., fifth generation (5G), 6G, etc.). The baseband circuitry 104 (e.g., one or more of baseband processors 104a-d) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 106. The radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some embodiments, modulation/demodulation circuitry of the baseband circuitry 104 may include Fast-Fourier Transform (FFT), precoding, and/or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 104 may include convolution, tail-biting convolution, turbo, Viterbi, and/or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments.

In some embodiments, the baseband circuitry 104 may include elements of a protocol stack such as, for example, elements of an D2D or evolved universal terrestrial radio access network (EUTRAN) protocol including, for example, physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and/or radio resource control (RRC) elements. A central processing unit (CPU) 104e of the baseband circuitry 104 may be configured to run elements of the protocol stack for signaling of the PHY, MAC, RLC, PDCP and/or RRC layers. In some embodiments, the baseband circuitry may include one or more audio digital signal processor(s) (DSP) 104f. The audio DSP(s) 104f may be include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments.

The baseband circuitry 104 may further include memory/storage 104g. The memory/storage 104g may be used to load and store data and/or instructions for operations performed by the processors of the baseband circuitry 104. Memory/storage for one embodiment may include any combination of suitable volatile memory and/or non-volatile memory. The memory/storage 104g may include any combination of various levels of memory/storage including, but not limited to, read-only memory (ROM) having embedded software instructions (e.g., firmware), random access memory (e.g., dynamic random access memory (DRAM)), cache, buffers, etc. The memory/storage 104g may be shared among the various processors or dedicated to particular processors.

Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry 104 and the application circuitry 102 may be implemented together such as, for example, on a system on a chip (SOC).

In some embodiments, the baseband circuitry 104 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 104 may support communication with an evolved universal terrestrial radio access network (EUTRAN) and/or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which the baseband circuitry 104 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

RF circuitry 106 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 106 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 106 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 108 and provide baseband signals to the baseband circuitry 104. RF circuitry 106 may also include a transmit signal path which may include circuitry to up- convert baseband signals provided by the baseband circuitry 104 and provide RF output signals to the FEM circuitry 108 for transmission.

In some embodiments, the RF circuitry 106 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 106 may include mixer circuitry 106a, amplifier circuitry 106b and filter circuitry 106c. The transmit signal path of the RF circuitry 106 may include filter circuitry 106c and mixer circuitry 106a. RF circuitry 106 may also include synthesizer circuitry 106d for synthesizing a frequency for use by the mixer circuitry 106a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 106a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 108 based on the synthesized frequency provided by synthesizer circuitry 106d. The amplifier circuitry 106b may be configured to amplify the down-converted signals and the filter circuitry 106c may be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided to the baseband circuitry 104 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 106a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 106a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by the synthesizer circuitry 106d to generate RF output signals for the FEM circuitry 108. The baseband signals may be provided by the baseband circuitry 104 and may be filtered by filter circuitry 106c. The filter circuitry 106c may include a low-pass filter (LPF), although the scope of the embodiments is not limited in this respect. In some embodiments, the mixer circuitry 106a of the receive signal path and the mixer circuitry 106a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and/or upconversion respectively. In some embodiments, the mixer circuitry 106a of the receive signal path and the mixer circuitry 106a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry 106a of the receive signal path and the mixer circuitry 106a may be arranged for direct downconversion and/or direct upconversion, respectively. In some embodiments, the mixer circuitry 106a of the receive signal path and the mixer circuitry 106a of the transmit signal path may be configured for super-heterodyne operation.

In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, the RF circuitry 106 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 104 may include a digital baseband interface to communicate with the RF circuitry 106.

In some embodiments, the synthesizer circuitry 106d may be a fractional -N synthesizer or a fractional N/N+l synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 106d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider.

The synthesizer circuitry 106d may be configured to synthesize an output frequency for use by the mixer circuitry 106a of the RF circuitry 106 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 106d may be a fractional N/N+l synthesizer.

In some embodiments, frequency input may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. Divider control input may be provided by either the baseband circuitry 104 or the applications processor 102 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table based on a channel indicated by the applications processor 102.

Synthesizer circuitry 106d of the RF circuitry 106 may include a divider, a delay- locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DP A). In some embodiments, the DMD may be configured to divide the input signal by either N or N+l (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

In some embodiments, synthesizer circuitry 106d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (fLO). In some embodiments, the RF circuitry 106 may include an IQ/polar converter.

FEM circuitry 108 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 110, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 106 for further processing. FEM circuitry 108 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 106 for transmission by one or more of the one or more antennas 110.

In some embodiments, the FEM circuitry 108 may include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include a low-noise amplifier (LNA) to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry 106). The transmit signal path of the FEM circuitry 108 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 106), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 110. In some embodiments, the electronic device 100 may include additional elements such as, for example, memory/storage, display, camera, sensor, and/or input/output (I/O) interface.

In embodiments where the electronic device 100 is, implements, is incorporated into, or is otherwise part of a user equipment (UE), baseband circuitry 104 may determine sidelink pathloss between a first UE and a second UE; and set at least one of a modulation and coding scheme (MCS) or a sidelink transmission power level based at least in part on the sidelink pathloss. RF circuitry 106 may send a signal based at least in part on the MCS or the sidelink transmission power level.

In some embodiments, baseband circuitry 104 may determine sidelink pathloss based at least in part on sidelink reference signal received power (SL-RSRP). In various embodiments, the baseband circuitry may determine sidelink pathloss based at least in part on a received indication of sidelink reference signal power (SL-referenceSignalPower). In some embodiments, the first UE may be a remote UE and the second UE may be a relay UE.

Figure 3 illustrates a UE or an e B in accordance with some embodiments. The device may be a D2D UE or an eNB that is configured to operate as or with a low-power wearable or IoT device. Control circuitry 301 may control various communication operations as described herein and may further control the transmission and reception of signals by the transmit/receive chain. Transmit/receive chain 303 may be a single transceiver chain.

In embodiments in which the electronic device illustrated in Figure 2 is used to implement the UE illustrated in Figure 3, control circuitry 301 may be implemented in parts of the baseband circuitry 104 and transmit/receive chain 303 may be implemented in parts of RF circuitry 106 and/or FEM circuitry 108. In embodiments, control circuitry 301 may determine sidelink pathloss between a UE and another UE; and set a modulation and coding scheme (MCS) or a sidelink transmission power level based on the sidelink pathloss. In embodiments, transmit/receive chain 303 may send/receive a signal based on the MCS or the sidelink transmission power level.

In some embodiments, the electronic devices of Figures 2-3 may be configured to perform one or more processes, techniques, and/or methods as described herein, or portions thereof. Figures 4-6 describe details of some of these processes, techniques, and/or methods.

Figure 4 illustrates a process 400 in accordance with some embodiments. The process 400 may be performed by a UE (for example, UE 120 or UE 130 of Figure 1). In some embodiments, the UE may include or have access to one or more non-transitory, computer-readable media having instructions stored thereon that, when executed, cause the UE to perform the process 400. In some embodiments, the process 400 may be performed by baseband circuitry 104 of Figure 2 or control circuitry 301 of Figure 3. Baseband circuitry 104 or control circuitry 301 may directly perform the operations of process 400 or may cause one or more other components to perform some or all of the operations of process 400.

For example, the process may include, at 401, determining sidelink pathloss between a first UE and a second UE, by the baseband circuitry 104 of Figure 2 or control circuitry 301 of Figure 3. In embodiments, baseband circuitry 104 or control circuitry 301 determines the sidelink pathloss based on a sidelink discovery reference signal received power (SD-RSRP), or a sidelink reference signal received power (SL-RSRP) measured over a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH).

The process 400 may further include, at 402, adapting a link for sidelink communication based at least in part on the sidelink pathloss, by the baseband circuitry 104 of Figure 2 or control circuitry 301 of Figure 3. In embodiments, adapting a link for sidelink communication may include setting a modulation and coding scheme (MCS) by the baseband circuitry 104 or control circuitry 301, based at least in part on the sidelink pathloss. In some embodiments, adapting the link for sidelink communication may include setting a sidelink transmission power level based at least in part on the sidelink pathloss.

Figure 5 illustrates a process 500 in accordance with some embodiments. The process 500 may be performed by a UE (for example, UE 120 or UE 130 of Figure 1). In some embodiments, the UE may include or have access to one or more non-transitory, computer-readable media having instructions stored thereon that, when executed, cause the UE to perform the process 500. In some embodiments, the process 500 may be performed by baseband circuitry 104 of Figure 2 or control circuitry 301 of Figure 3. Baseband circuitry 104 or control circuitry 301 may directly perform the operations of process 500 or may cause one or more other components to perform some or all of the operations of process 500.

For example, the electronic device of Figures 2-3 may: measure, by baseband circuitry 104, a sidelink received signal strength indication (S-RSSI), and a sidelink interference signal strength indication (S-ISSI) (501); measure a sidelink reference signal received power (SL-RSRP) over a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH) (503); determine a physical sidelink shared channel reference signal received quality (S-RSRQ) based on the S-RSSI, the S-ISSI, and the SL-RSRP (505); set a sidelink transmission modulation and coding scheme (MCS) based on the S-RSRQ (507); and cause a signal to be sent based on the MCS (509).

Figure 6 illustrates a process 600 in accordance with some embodiments. The process 400 may be performed by a UE (for example, UE 120 or UE 130 of Figure 1). In some embodiments, the UE may include or have access to one or more non-transitory, computer-readable media having instructions stored thereon that, when executed, cause the UE to perform the process 600. In some embodiments, the process 600 may be performed by baseband circuitry 104 of Figure 2 or control circuitry 301 of Figure 3. Baseband circuitry 104 or control circuitry 301 may directly perform the operations of process 600 by a processing circuitry within baseband circuitry 104 or control circuitry 301 or may cause one or more other processing circuitry to perform some or all of the operations of process 600.

For example, the electronic device of Figures 2-3 may: determine, by baseband circuitry 104, a sidelink reference signal power (SL-referenceSignalPower) from a received indication of SL-referenceSignalPower (601); measure a sidelink discovery reference signal received power (SD-RSRP), or a sidelink reference signal received power (SL-RSRP) over a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH) (603); determine sidelink pathloss between the UE and another UE based on the SL-referenceSignalPower, and the SL-RSRP or the SD-RSRP (605); and set a sidelink transmission power level based on the sidelink pathloss (607).

EXAMPLES

Example 1 may include a user equipment (UE) for device-to-device (D2D) communication in a mobile communication network, comprising:

baseband circuitry to:

determine sidelink pathloss between the UE and another UE; and set a modulation and coding scheme (MCS) or a sidelink transmission power level based on the sidelink pathloss; and

radio frequency (RF) circuitry coupled with the baseband circuitry to send a signal based on the MCS or the sidelink transmission power level. Example 2 may include the UE of example 1 and/or some other examples herein, wherein the baseband circuitry is to determine the sidelink pathloss based on a sidelink discovery reference signal received power (SD-RSRP), or a sidelink reference signal received power (SL-RSRP) measured over a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH).

Example 3 may include the UE of example 1 and/or some other examples herein, wherein the baseband circuitry is to determine the sidelink pathloss based on a received indication of sidelink reference signal power (SL-referenceSignalPower).

Example 4 may include the UE of example 3 and/or some other examples herein, wherein the received indication of SL-referenceSignalPower is signaled in a physical sidelink discovery channel (PSDCH) payload as an energy-per-resource element (EPRE) of a sidelink demodulation reference signal (DMRS).

Example 5 may include the UE of any one of examples 1-4 and/or some other examples herein, wherein the baseband circuitry is to determine the sidelink pathloss based on a first link from the UE to another UE, or a second link from another UE to the UE.

Example 6 may include the UE of any one of examples 1-4 and/or some other examples herein, wherein:

the baseband circuitry is further to measure a physical sidelink shared channel reference signal received quality (S-RSRQ), a sidelink received signal strength indication (S-RSSI), or a sidelink interference signal strength indication (S-ISSI); and

the RF circuitry is further to send a measurement signal reporting the S-RSRQ, the S-RSSI, or the S-ISSI to another UE.

Example 7 may include the UE of example 6 and/or some other examples herein, wherein the S-RSRQ is calculated based on the S-RSSI, the S-ISSI, and the sidelink reference signal received power (SL-RSRP) measured over the physical sidelink shared channel (PSSCH).

Example 8 may include the UE of example 7 and/or some other examples herein, wherein the S-RSSI or the S-ISSI is received from another UE, the S-RSSI or the S-ISSI is either measured by another UE or calculated by another UE.

Example 9 may include the UE of any one of examples 6-7 and/or some other examples herein, wherein the RF circuitry is to send the measurement signal using a medium access control (MAC) control element (CE) or a radio resource control (RRC) message.

Example 10 may include the UE of example 9 and/or some other examples herein, wherein the RF circuitry is to send the measurement signal using the MAC CE that includes a measurement identifier (ID), a measurement type, a counter, or an averaged measurement.

Example 11 may include a computer-readable medium comprising instructions to cause a user equipment (UE), upon execution of the instructions by one or more processors, to:

measure a sidelink received signal strength indication (S-RSSI), and a sidelink interference signal strength indication (S-ISSI);

measure a sidelink reference signal received power (SL-RSRP) over a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH);

determine a physical sidelink shared channel reference signal received quality (S-

RSRQ) based on the S-RSSI, the S-ISSI, and the SL-RSRP;

set a sidelink transmission modulation and coding scheme (MCS) based on the S- RSRQ; and

cause a signal to be sent based on the MCS.

Example 12 may include the computer-readable medium of example 11 and/or some other examples herein, wherein the instructions further cause the UE, upon execution of the instructions by the processor, to:

measure a sidelink discovery reference signal received power (SD-RSRP).

Example 13 may include the computer-readable medium of any one of examples 11-12 and/or some other examples herein, wherein the instructions further cause the UE, upon execution of the instructions by the processor, to:

determine a sidelink reference signal power (SL-referenceSignalPower) based on a received indication.

Example 14 may include the computer-readable medium of example 13 and/or some other examples herein, wherein the received indication of SL-referenceSignalPower is signaled in a physical sidelink discovery channel (PSDCH) payload as an energy-per- resource element (EPRE) of a sidelink demodulation reference signal (DMRS). Example 15 may include the computer-readable medium of any one of examples 11-14 and/or some other examples herein, wherein the instructions further cause the UE, upon execution of the instructions by the processor, to:

determine sidelink pathloss between the UE and another UE based on the SL- RSRP or the SD-RSRP, and the SL-referenceSignalPower;

set a sidelink transmission power level based on the sidelink pathloss; and cause a second signal to be sent based on the sidelink transmission power level.

Example 16 may include the computer-readable medium of example 15 and/or some other examples herein, wherein the sidelink pathloss is determined based on a first link from the UE to another UE, or a second link from another UE to the UE.

Example 17 may include the computer-readable medium of example 11 and/or some other examples herein, wherein the instructions further cause the UE, upon execution of the instructions by the processor, to:

cause a measurement signal to be sent reporting the S-RSSI, the S-ISSI, or the measured S-RSRQ, using a medium access control (MAC) control element (CE) or a radio resource control (RRC) message.

Example 18 may include the computer-readable medium of example 17 and/or some other examples herein, wherein the measurement signal is sent using the MAC CE that includes a measurement identifier (ID) and a measurement type.

Example 19 may include the computer-readable medium of example 17 and/or some other examples herein, wherein the measurement signal is sent using the MAC CE that includes an averaged measurement, a measurement identifier (ID), a measurement type, and a counter.

Example 20 may include an apparatus to be used in a user equipment (UE) for device-to-device (D2D) communication in a mobile communication network, comprising: a memory storing instructions; and

a processing circuitry to execute the instructions stored in the memory to:

determine a sidelink reference signal power (SL-referenceSignalPower) from a received indication of SL-referenceSignalPower;

measure a sidelink discovery reference signal received power (SD-RSRP), or a sidelink reference signal received power (SL-RSRP) over a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH);

determine sidelink pathloss between the UE and another UE based on the SL-referenceSignalPower, and the SL-RSRP or the SD-RSRP; and set a sidelink transmission power level based on the sidelink pathloss. Example 21 may include the apparatus of example 20 and/or some other examples herein, wherein the received indication of SL-referenceSignalPower is signaled in a physical sidelink discovery channel (PSDCH) payload as an energy-per-resource element (EPRE) of a sidelink demodulation reference signal (DMRS).

Example 22 may include the apparatus of any one of examples 20-21 and/or some other examples herein, wherein the processing circuitry is to determine the sidelink pathloss based on a first link from the UE to another UE, or a second link from another UE to the UE.

Example 23 may include the apparatus of any one of examples 20-22 and/or some other examples herein, wherein:

the processing circuitry is further to:

measure or calculate a physical sidelink shared channel reference signal received quality (S-RSRQ) based on the S-RSSI, the S-ISSI, and the SL-RSRP; and

set a sidelink transmission modulation and coding scheme (MCS) based on the S-RSRQ; and

the apparatus further comprising:

a radio frequency (RF) circuitry to send a signal based on the MCS.

Example 24 may include the apparatus of example 23 and/or some other examples herein, wherein the RF circuitry is further to send a measurement signal reporting the S- RSSI or the S-ISSI using a medium access control (MAC) control element (CE) including a measurement identifier (ID) and a measurement type, or using a radio resource control (RRC) message.

Example 25 may include the apparatus of any one of examples 20-24 and/or some other examples herein, wherein the UE is a remote UE or a relay UE.

Example 26 may include an apparatus for device-to-device (D2D) communication in a mobile communication network, comprising:

means for determining sidelink pathloss between a UE and another UE; and means for setting a modulation and coding scheme (MCS) or a sidelink

transmission power level based on the sidelink pathloss; and

means for sending a signal based on the MCS or the sidelink transmission power level. Example 27 may include the apparatus of example 26 and/or some other examples herein, wherein means for determining sidelink pathloss comprises means for determining the sidelink pathloss based on a sidelink discovery reference signal received power (SD- RSRP), or a sidelink reference signal received power (SL-RSRP) measured over a physical sidelink control channel (PSCCH) or a physical sidelink shared channel

(PSSCH).

Example 28 may include the apparatus of example 26 and/or some other examples herein, wherein means for determining sidelink pathloss comprises means for determining the sidelink pathloss based on a received indication of sidelink reference signal power (SL-referenceSignalPower).

Example 29 may include the apparatus of example 28 and/or some other examples herein, wherein the received indication of SL-referenceSignalPower is signaled in a physical sidelink discovery channel (PSDCH) payload as an energy-per-resource element (EPRE) of a sidelink demodulation reference signal (DMRS).

Example 30 may include the apparatus of any one of examples 26-29 and/or some other examples herein, wherein means for determining sidelink pathloss comprises means for determining the sidelink pathloss based on a first link from the UE to another UE, or a second link from another UE to the UE.

Example 31 may include the apparatus of any one of examples 26-29 and/or some other examples herein, further comprising:

means for measuring a physical sidelink shared channel reference signal received quality (S-RSRQ), a sidelink received signal strength indication (S-RSSI), or a sidelink interference signal strength indication (S-ISSI); and

means for sending a measurement signal reporting the S-RSRQ, the S-RSSI, or the S-ISSI to another UE.

Example 32 may include the apparatus of example 31 and/or some other examples herein, wherein the S-RSRQ is calculated based on the S-RSSI, the S-ISSI, and the sidelink reference signal received power (SL-RSRP) measured over the physical sidelink shared channel (PSSCH).

Example 33 may include the apparatus of example 32 and/or some other examples herein, wherein the S-RSSI or the S-ISSI is received from another UE, the S-RSSI or the S-ISSI is either measured by another UE or calculated by another UE.

Example 34 may include the apparatus of any one of examples 32-33 and/or some other examples herein, wherein means for sending the measurement signal comprises means for sending the measurement signal using a medium access control (MAC) control element (CE) or a radio resource control (RRC) message.

Example 35 may include the apparatus of example 34 and/or some other examples herein, wherein means for sending the measurement signal comprises means for sending the measurement signal using the MAC CE that includes a measurement identifier (ID), a measurement type, a counter, or an averaged measurement.

Example 36 may include an apparatus for device-to-device (D2D) communication in a mobile communication network, comprising:

means for measuring a sidelink received signal strength indication (S-RSSI), and a sidelink interference signal strength indication (S-ISSI);

means for measuring a sidelink reference signal received power (SL-RSRP) over a physical sidelink control channel (PSCCH) or a physical sidelink shared channel

(PSSCH);

means for determining a physical sidelink shared channel reference signal received quality (S-RSRQ) based on the S-RSSI, the S-ISSI, and the SL-RSRP;

means for setting a sidelink transmission modulation and coding scheme (MCS) based on the S-RSRQ; and

means for causing a signal to be sent based on the MCS.

Example 37 may include the apparatus of example 36 and/or some other examples herein, further comprising:

means for measuring a sidelink discovery reference signal received power (SD-

RSRP).

Example 38 may include the apparatus of any one of examples 36-37 and/or some other examples herein, further comprising:

means for determining a sidelink reference signal power (SL- referenceSignalPower) based on a received indication.

Example 39 may include the apparatus of example 38 and/or some other examples herein, wherein the received indication of SL-referenceSignalPower is signaled in a physical sidelink discovery channel (PSDCH) payload as an energy-per-resource element (EPRE) of a sidelink demodulation reference signal (DMRS).

Example 40 may include the apparatus of any one of examples 36-39 and/or some other examples herein, further comprising:

means for determining sidelink pathloss between the UE and another UE based on the SL-RSRP or the SD-RSRP, and the SL-referenceSignalPower; means for setting a sidelink transmission power level based on the sidelink pathloss; and

means for causing a second signal to be sent based on the sidelink transmission power level.

Example 41 may include the apparatus of example 40 and/or some other examples herein, wherein the sidelink pathloss is determined based on a first link from the UE to another UE, or a second link from another UE to the UE.

Example 42 may include the apparatus of example 36 and/or some other examples herein, further comprising:

means for causing a measurement signal to be sent reporting the S-RSSI, the S-

ISSI, or the measured S-RSRQ, using a medium access control (MAC) control element (CE) or a radio resource control (RRC) message.

Example 43 may include the apparatus of example 42 and/or some other examples herein, wherein means for causing a measurement signal to be sent comprises means for sending the measurement signal using the MAC CE that includes a measurement identifier (ID) and a measurement type.

Example 44 may include the apparatus of example 42 and/or some other examples herein, wherein means for causing a measurement signal to be sent comprises means for sending the measurement signal using the MAC CE that includes an averaged

measurement, a measurement identifier (ID), a measurement type, and a counter.

Example 45 may include an apparatus for device-to-device (D2D) communication in a mobile communication network, comprising:

means for determining a sidelink reference signal power (SL- referenceSignalPower) from a received indication of SL-referenceSignalPower;

means for measuring a sidelink discovery reference signal received power (SD-

RSRP), or a sidelink reference signal received power (SL-RSRP) over a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH);

means for determining sidelink pathloss between a user equipment (UE) and another UE based on the SL-referenceSignalPower, and the SL-RSRP or the SD-RSRP; and

means for setting a sidelink transmission power level based on the sidelink pathloss.

Example 46 may include the apparatus of example 45 and/or some other examples herein, wherein the received indication of SL-referenceSignalPower is signaled in a physical sidelink discovery channel (PSDCH) payload as an energy-per-resource element (EPRE) of a sidelink demodulation reference signal (DMRS).

Example 47 may include the apparatus of any one of examples 45-46 and/or some other examples herein, further comprising:

means for determining the sidelink pathloss based on a first link from the UE to another UE, or a second link from another UE to the UE.

Example 48 may include the apparatus of any one of examples 45-47 and/or some other examples herein, further comprising:

means for measuring or calculate a physical sidelink shared channel reference signal received quality (S-RSRQ) based on the S-RSSI, the S-ISSI, and the SL-RSRP; means for setting a sidelink transmission modulation and coding scheme (MCS) based on the S-RSRQ; and

means for sending a signal based on the MCS.

Example 49 may include the apparatus of example 48 and/or some other examples herein, further comprising:

means for sending a measurement signal reporting the S-RSSI or the S-ISSI using a medium access control (MAC) control element (CE) including a measurement identifier (ID) and a measurement type, or using a radio resource control (RRC) message.

Example 50 may include the apparatus of any one of examples 45-49 and/or some other examples herein, wherein the UE is a remote UE or a relay UE.

Example 51 may include a method for device-to-device (D2D) communication in a mobile communication network, comprising:

determining sidelink pathloss between a UE and another UE; and

setting a modulation and coding scheme (MCS) or a sidelink transmission power level based on the sidelink pathloss; and

sending a signal based on the MCS or the sidelink transmission power level.

Example 52 may include the method of example 51 and/or some other examples herein, further comprising:

measuring a physical sidelink shared channel reference signal received quality (S- RSRQ), a sidelink received signal strength indication (S-RSSI), or a sidelink interference signal strength indication (S-ISSI); and sending a measurement signal reporting the S-RSRQ, the S-RSSI, or the S-ISSI to another UE.

Example 53 may include a method for device-to-device (D2D) communication in a mobile communication network, comprising:

measuring a sidelink received signal strength indication (S-RSSI), and a sidelink interference signal strength indication (S-ISSI);

measuring a sidelink reference signal received power (SL-RSRP) over a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH);

determining a physical sidelink shared channel reference signal received quality (S-RSRQ) based on the S-RSSI, the S-ISSI, and the SL-RSRP;

setting a sidelink transmission modulation and coding scheme (MCS) based on the S-RSRQ; and

causing a signal to be sent based on the MCS.

Example 54 may include the method of example 53 and/or some other examples herein, further comprising:

measuring a sidelink discovery reference signal received power (SD-RSRP).

Example 55 may include the method of any one of examples 53-54 and/or some other examples herein, further comprising:

determining a sidelink reference signal power (SL-referenceSignalPower) based on a received indication.

Example 56 may include the method of any one of examples 53-55 and/or some other examples herein, further comprising:

determining sidelink pathloss based on the SL-RSRP or the SD-RSRP, and the SL- referenceSignalPower;

setting a sidelink transmission power level based on the sidelink pathloss; and causing a second signal to be sent based on the sidelink transmission power level. Example 57 may include the method of example 53 and/or some other examples herein, further comprising:

causing a measurement signal to be sent reporting the S-RSSI, the S-ISSI, or the measured S-RSRQ, using a medium access control (MAC) control element (CE) or a radio resource control (RRC) message.

Example 58 may include a method for device-to-device (D2D) communication in a mobile communication network, comprising: determining a sidelink reference signal power (SL-referenceSignalPower) from a received indication of SL-referenceSignalPower;

measuring a sidelink discovery reference signal received power (SD-RSRP), or a sidelink reference signal received power (SL-RSRP) over a physical sidelink control channel (PSCCH) or a physical sidelink shared channel (PSSCH);

determining sidelink pathloss between a user equipment (UE) and another UE based on the SL-referenceSignalPower, and the SL-RSRP or the SD-RSRP; and

setting a sidelink transmission power level based on the sidelink pathloss.

Example 59 may include the method of example 58 and/or some other examples herein, further comprising:

determining the sidelink pathloss based on a first link from a UE to another UE, or a second link from another UE to the UE.

Example 60 may include the method of any one of examples 58-59 and/or some other examples herein, further comprising:

measuring or calculate a physical sidelink shared channel reference signal received quality (S-RSRQ) based on the S-RSSI, the S-ISSI, and the SL-RSRP;

sending a signal based on the MCS.

Example 61 may include the method of example 58 and/or some other examples herein, further comprising:

sending a measurement signal reporting the S-RSSI or the S-ISSI using a medium access control (MAC) control element (CE) including a measurement identifier (ID) and a measurement type, or using a radio resource control (RRC) message.

The foregoing description of one or more implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of embodiments to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments.

Claims

CLAIMS What is claimed is:

1. A user equipment (UE) for device-to-device (D2D) communication in a mobile communication network, comprising:

baseband circuitry to:

radio frequency (RF) circuitry coupled with the baseband circuitry to send a signal based on the MCS or the sidelink transmission power level.

2. The UE of claim 1, wherein the baseband circuitry is to determine the sidelink pathloss based on a sidelink discovery reference signal received power (SD- RSRP), or a sidelink reference signal received power (SL-RSRP) measured over a physical sidelink control channel (PSCCH) or a physical sidelink shared channel

(PSSCH).

3. The UE of claim 1, wherein the baseband circuitry is to determine the sidelink pathloss based on a received indication of sidelink reference signal power (SL- referenceSignalPower).

4. The UE of claim 3, wherein the received indication of SL- referenceSignalPower is signaled in a physical sidelink discovery channel (PSDCH) payload as an energy-per-resource element (EPRE) of a sidelink demodulation reference signal (DMRS).

5. The UE of any one of claims 1-4, wherein the baseband circuitry is to determine the sidelink pathloss based on a first link from the UE to another UE, or a second link from another UE to the UE.

6. The UE of any one of claims 1-4, wherein:

the RF circuitry is further to send a measurement signal reporting the S-RSRQ, the

S-RSSI, or the S-ISSI to another UE.

7. The UE of claim 6, wherein the S-RSRQ is calculated based on the S-RSSI, the S-ISSI, and the sidelink reference signal received power (SL-RSRP) measured over the physical sidelink shared channel (PSSCH).

8. The UE of claim 7, wherein the S-RSSI or the S-ISSI is received from another UE, the S-RSSI or the S-ISSI is either measured by another UE or calculated by another UE.

9. The UE of any one of claims 1-4, wherein the RF circuitry is to send the measurement signal using a medium access control (MAC) control element (CE) or a radio resource control (RRC) message.

10. The UE of claim 9, wherein the RF circuitry is to send the measurement signal using the MAC CE that includes a measurement identifier (ID), a measurement type, a counter, or an averaged measurement.

11. A computer-readable medium comprising instructions to cause a user equipment (UE), upon execution of the instructions by one or more processors, to:

determine a physical sidelink shared channel reference signal received quality (S- RSRQ) based on the S-RSSI, the S-ISSI, and the SL-RSRP;

cause a signal to be sent based on the MCS.

12. The computer-readable medium of claim 11, wherein the instructions further cause the UE, upon execution of the instructions by the processor, to:

measure a sidelink discovery reference signal received power (SD-RSRP).

13. The computer-readable medium of any one of claims 11-12, wherein the instructions further cause the UE, upon execution of the instructions by the processor, to: determine a sidelink reference signal power (SL-referenceSignalPower) based on a received indication.

14. The computer-readable medium of claim 13, wherein the received indication of SL-referenceSignalPower is signaled in a physical sidelink discovery channel (PSDCH) payload as an energy-per-resource element (EPRE) of a sidelink demodulation reference signal (DMRS).

15. The computer-readable medium of any one of claims 11-12, wherein the instructions further cause the UE, upon execution of the instructions by the processor, to: determine sidelink pathloss between the UE and another UE based on the SL-

RSRP or the SD-RSRP, and the SL-referenceSignalPower;

16. The computer-readable medium of claim 15, wherein the sidelink pathloss is determined based on a first link from the UE to another UE, or a second link from another UE to the UE.

17. The computer-readable medium of claim 11, wherein the instructions further cause the UE, upon execution of the instructions by the processor, to:

18. The computer-readable medium of claim 17, wherein the measurement signal is sent using the MAC CE that includes a measurement identifier (ID) and a measurement type.

19. The computer-readable medium of claim 17, wherein the measurement signal is sent using the MAC CE that includes an averaged measurement, a measurement identifier (ID), a measurement type, and a counter.

20. An apparatus to be used in a user equipment (UE) for device-to-device (D2D) communication in a mobile communication network, comprising:

a memory storing instructions; and

a processing circuitry to execute the instructions stored in the memory to:

determine sidelink pathloss between the UE and another UE based on the SL-referenceSignalPower, and the SL-RSRP or the SD-RSRP; and

set a sidelink transmission power level based on the sidelink pathloss.

21. The apparatus of claim 20, wherein the received indication of SL- referenceSignalPower is signaled in a physical sidelink discovery channel (PSDCH) payload as an energy-per-resource element (EPRE) of a sidelink demodulation reference signal (DMRS).

22. The apparatus of any one of claims 20-21, wherein the processing circuitry is to determine the sidelink pathloss based on a first link from the UE to another UE, or a second link from another UE to the UE.

23. The apparatus of any one of claims 20-21, wherein:

the processing circuitry is further to:

the apparatus further comprising:

a radio frequency (RF) circuitry to send a signal based on the MCS.

24. The apparatus of claim 23, wherein the RF circuitry is further to send a measurement signal reporting the S-RSSI or the S-ISSI using a medium access control (MAC) control element (CE) including a measurement identifier (ID) and a measurement type, or using a radio resource control (RRC) message.

25. The apparatus of any one of claims 20-21, wherein the UE is a remote UE or a relay UE.