Patent Description:
Currently, in a narrowband internet of things (Narrow Band Internet of Things, NB-IoT) system, transmit power is determined in an open-loop power control manner in uplink transmission. For a signal on a narrowband physical random access channel (Narrowband Physical Random Access Channel, NPRACH) in the NB-IoT system: When the signal is at a coverage level <NUM>, a terminal device enables open-loop power control to determine transmit power of the signal on the NPRACH. When the signal is at a coverage level <NUM> or <NUM>, the signal is directly sent on the NPRACH based on a maximum transmit power of the terminal device. In many cases, the terminal device directly uses the maximum transmit power to send the signal. <CIT> discloses a method of access and link adaptation for coverage in coverage enhanced wireless transmissions, particularly, based on path loss as well as power control based on either open loop calculation or RSRP or path loss. In a paper by <NPL>, the control of transmission power based on an open loop power control method is disclosed.

However, in an interference-limited communications network or a communications network with relatively heavy load, the method for determining transmit power in the prior art easily aggravates mutual interference between signals of terminal devices. Therefore, a method to resolve a problem of the signal interference between the terminal devices needs to be proposed.

Embodiments of this application provide a signal transmission method and a terminal device, which can reduce interference to uplink transmission of another terminal device.

According to a first aspect, a signal transmission method is provided, including:.

In this embodiment of this application, the terminal device may determine the first transmit power based on the access status of the terminal device at the current coverage level and/or the first power control parameter, and transmit the signal at the first transmit power, so as to reduce interference between terminal devices.

Therefore, the terminal device may select or calculate a proper first transmit power based on the first determining information and the first power control parameter, and does not need to directly transmit an uplink signal at the maximum transmit power, thereby reducing interference to uplink transmission of another terminal device.

Optionally, the determining, by the terminal device, the first transmit power based on the first power control parameter includes:
when the reference signal received power RSRP value measured by the terminal device is greater than a first RSRP threshold, using, by the terminal device, the maximum transmit power of the terminal device as the transmit power, where the first RSRP threshold is notified by a network device to the terminal device.

Therefore, the terminal device may select or calculate a proper first transmit power based on the power control parameter, and does not need to directly transmit an uplink signal at the maximum transmit power, thereby reducing interference to uplink transmission of another terminal device.

Optionally, the calculating the transmit power by using an open-loop power control calculation method includes:.

The foregoing formulas are merely used as an example herein to describe the open-loop power control calculation method, and there may be another possible open-loop power control calculation manner in the future.

According to a second aspect, a signal transmission method is provided, including:.

Therefore, the network device receives the signal transmitted by the terminal device at the first transmit power, and the first transmit power is determined by the terminal device based on the access status of the terminal device at the current coverage level and/or the first power control parameter, thereby reducing interference between terminal devices.

According to a third aspect, a terminal device is provided and is configured to perform the method according to any one of the first aspect or the possible implementations of the first aspect. Specifically, the terminal device includes modules configured to perform the method according to any one of the first aspect or the possible implementations of the first aspect.

According to a fourth aspect, a network device is provided and is configured to perform the method according to any one of the second aspect or the possible implementations of the second aspect. Specifically, the network device includes modules configured to perform the method according to any one of the second aspect or the possible implementations of the second aspect.

According to a fifth aspect, a terminal device is provided. The terminal device includes a processor, a memory, and a communications interface. The processor is connected to the memory and the communications interface. The memory is configured to store an instruction, the processor is configured to execute the instruction, and the communications interface is configured to communicate with another network element under control of the processor. When the processor executes the instruction stored in the memory, the processor is enabled to perform the method according to any one of the first aspect or the possible implementations of the first aspect.

According to a sixth aspect, a network device is provided. The network device includes a processor, a memory, and a communications interface. The processor is connected to the memory and the communications interface. The memory is configured to store an instruction, the processor is configured to execute the instruction, and the communications interface is configured to communicate with another network element under control of the processor. When the processor executes the instruction stored in the memory, the processor is enabled to perform the method according to any one of the first aspect or the possible implementations of the first aspect.

According to a seventh aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores a program, and the program enables a terminal device to perform the signal transmission method according to any one of the first aspect and the implementations of the first aspect.

According to an eighth aspect, a computer-readable storage medium is provided. The computer-readable storage medium stores a program. The program enables a network device to perform the signal transmission method according to any one of the second aspect and the implementations of the second aspect.

It should be understood that the technical solutions in the embodiments of this application may be applied to various communications systems or internet of things (Internet of Things, IoT) systems, for example, existing systems such as a global system for mobile communications (Global System of Mobile communications, GSM), a code division multiple access (Code Division Multiple Access, CDMA) system, a wideband code division multiple access (Wideband Code Division Multiple Access, WCDMA) system, a general packet radio service (General Packet Radio Service, GPRS), a long term evolution (Long Term Evolution, LTE) system, an LTE frequency division duplex (Frequency Division Duplex, FDD) system, an LTE time division duplex (Time Division Duplex, TDD) system, a universal mobile telecommunications system (Universal Mobile Telecommunications System, UMTS), and a narrowband internet of things (Narrow Band Internet of Things, NB-IoT) system; and in particular, applied to a future <NUM> new radio (New Radio, NR) system or an <NUM> system, or a communications system based on an orthogonal frequency division multiplexing (Orthogonal Frequency Division Multiplexing, OFDM) technology.

It should further be understood that in the embodiments of this application, a network device may be referred to as a network device side, a base station, or the like. The base station may be a base transceiver station (Base Transceiver Station, BTS) in a GSM or CDMA system, may be a NodeB (NodeB) in a WCDMA system, and may be an evolved NodeB (Evolutional NodeB, eNB, or eNodeB) in LTE, or a gNB in a future <NUM> network. This is not limited in this application.

It should be further understood that in the embodiments of this application, a terminal device may communicate with one or more core networks (Core Network) by using a radio access network (Radio Access Network, RAN). The terminal device may be referred to as an access terminal, user equipment (User Equipment, UE), a subscriber unit, a subscriber station, a mobile station (Mobile Station), a mobile (Mobile) console, a remote station, a remote terminal (Remote Terminal), a mobile device, a user terminal (User Terminal), a terminal, radio communications equipment, a user agent (User Agent), or a user device (User Device). The terminal device may be a cellular phone, a cordless phone, a session initiation protocol (Session Initiation Protocol, SIP) phone, a wireless local loop (Wireless Local Loop, WLL) station, a personal digital processing (Personal Digital Assistant, PDA), a handheld device with a wireless communication function, a device providing voice and/or data connectivity for a user, a handheld device with a wireless connection function, a computing device, or another processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a future <NUM> network, or the like.

<FIG> is a schematic diagram of a scenario. It should be understood that, for ease of understanding, herein the scenario in <FIG> is introduced as an example for description, but does not constitute any limitation to this application. <FIG> shows a terminal device <NUM>, a terminal device <NUM>, a terminal device <NUM>, and a base station <NUM>.

As shown in <FIG>, the terminal device <NUM> may communicate with the base station <NUM>, the terminal device <NUM> may communicate with the base station <NUM>, and the terminal device <NUM> communicates with the base station <NUM>. Alternatively, the terminal device <NUM> may communicate with the terminal device <NUM>. Alternatively, in another case, the terminal device <NUM> communicates with the terminal device <NUM>.

<FIG> is a schematic flowchart of a signal transmission method <NUM> according to an embodiment of this application. The method <NUM> may be performed by a terminal device. For example, the terminal device may be the terminal device <NUM>, the terminal device <NUM>, or the terminal device <NUM> in <FIG>. Correspondingly, a network device communicating with the terminal device may be the base station <NUM> in <FIG>. As shown in <FIG>, the method <NUM> includes the following steps:
S210. The terminal device determines a first transmit power based on an access status of the terminal device at a current coverage level and/or a first power control parameter.

Optionally, the access status of the terminal device at the current coverage level may be represented by using first determining information.

Optionally, the terminal device may actively learn of the first determining information. Alternatively, the terminal device may obtain the first determining information from the network device. This is not limited.

Optionally, the first power control parameter includes at least one of the following parameters:
reference signal received power (Reference Signal Received Power RSRP), a downlink path loss, a transmission bandwidth parameter, a maximum transmit power of the terminal device, a preamble target received power, an initial preamble target received power, an initial transmit power, a preamble power offset, a quantity of preamble attempts, a power ramping step, a path loss conversion proportional coefficient, repetition times for sending a preamble, and a power indication parameter. Optionally, the power indication parameter may be used to indicate a parameter that may be used by the terminal device in a power control process and that is other than the foregoing several parameters, or a power parameter that may appear in the future or may be newly introduced in the future. For example, the power indication parameter may be a power adjustment factor.

Optionally, the first determining information may indicate the access status of the terminal device at the current coverage level. For example, the first determining information may be used to indicate that the terminal device selects the current coverage level during initial random access. For example, the first determining information may be used to indicate that the terminal device selects a coverage level <NUM>, a coverage level <NUM>, or a coverage level <NUM> during first random access.

Alternatively, the first determining information may be used to indicate that the terminal device is switched from a non-current coverage level to the current coverage level. For example, the first determining information indicates that the terminal device is switched from a coverage level <NUM> to a coverage level <NUM>, or indicates that the terminal device is switched from a coverage level <NUM> to a coverage level <NUM>. Specifically, for example, the terminal device may select the coverage level <NUM> if the terminal device attempts a plurality of times and access fails at the coverage level <NUM>. Alternatively, the terminal device may select the coverage level <NUM> if the terminal device attempts a plurality of times and access fails at the coverage level <NUM>.

The terminal device transmits a signal at the first transmit power.

Specifically, the terminal device may determine the first transmit power based on the access status of the terminal device at the current coverage level and/or the first power control parameter, and transmit a signal on a narrowband physical random access channel (Narrowband Physical Random Access Channel, NPRACH) at the first transmit power. In other words, the terminal device may select a proper transmit power based on an actual requirement, to transmit an uplink signal relatively quickly, and to reduce interference to uplink transmission of another terminal device.

In this embodiment of this application, the terminal device may determine the first transmit power based on the access status of the terminal device at the current coverage level and/or the first power control parameter, thereby reducing interference between terminal devices. However, in the prior art, the terminal device can transmit a signal based only on a default maximum transmit power at some coverage levels, which causes relatively large interference to uplink transmission of another terminal device.

The following uses an example in which "the first determining information indicates the access status of the terminal device at the current coverage level" for description. However, "the first determining information" may not be introduced in practice. This is not limited in this embodiment of this application.

Optionally, in an embodiment, that the terminal device determines the first transmit power based on the first determining information and/or the first power control parameter includes:
determining, by the terminal device, the first transmit power based on the first determining information and the first power control parameter.

Specifically, the terminal device may calculate the first transmit power with reference to the first determining information and the first power control parameter.

Optionally, the determining, by the terminal, the first transmit power based on the first determining information and the first power control parameter includes:.

Specifically, in a first case: If the first determining information indicates that the terminal device is switched from the non-current coverage level to the current coverage level, the terminal device may calculate the first transmit power by using the open-loop power control calculation method. Alternatively, in a second case: If the first determining information indicates that the terminal device selects the current coverage level during initial random access, the terminal device may calculate the first transmit power by using the open-loop power control calculation method. It should be noted that the at least one of the first power control parameters used by the terminal device in the first case is different from that used in the second case. The non-current coverage level is different from the current coverage level.

For example, it is assumed that the current coverage level is the coverage level <NUM>. In the first case, the terminal device is switched from the coverage level <NUM> to the coverage level <NUM>, and then the terminal device may calculate the first transmit power by using the open-loop power control calculation method. In the second case, the terminal device selects the coverage level <NUM> during initial random access, and then the terminal device may calculate the first transmit power by using the open-loop power control calculation method. The at least one of the first power control parameters used by the terminal device in the first case is different from that used in the second case.

Optionally, when the first determining information indicates that the terminal device is switched from a non-current coverage level to the current coverage level, the terminal device calculates the first transmit power based on at least one of the first power control parameters by using an open-loop power control calculation method.

When the first determining information indicates that the terminal device selects the current coverage level during initial random access, the terminal device uses a maximum transmit power of the terminal device as the first transmit power.

Specifically, in a first case: If the first determining information indicates that the terminal device is switched from the non-current coverage level to the current coverage level, the terminal device may calculate the first transmit power by using the open-loop power control calculation method. In a second case: If the first determining information indicates that the terminal device selects the current coverage level during initial random access, the terminal device may use a maximum transmit power of the terminal device as the first transmit power.

Alternatively, optionally, when the first determining information indicates that the terminal device is switched from a non-current coverage level to the current coverage level, the terminal device uses a maximum transmit power of the terminal device as the first transmit power.

When the first determining information indicates that the terminal device selects the current coverage level during initial random access, the terminal device calculates the first transmit power based on at least one of the first power control parameters by using an open-loop power control calculation method.

Specifically, in a first case: If the first determining information indicates that the terminal device is switched from the non-current coverage level to the current coverage level, the terminal device may use the maximum transmit power of the terminal device as the first transmit power. In a second case: If the first determining information indicates that the terminal device selects the current coverage level during initial random access, the terminal device may calculate the first transmit power by using the open-loop power control calculation method.

Optionally, in an embodiment, that the terminal determines the first transmit power based on the first determining information and the first power control parameter includes:.

Specifically, in a first case: If the first determining information indicates that the terminal device is switched from the non-current coverage level to the current coverage level, and the RSRP value measured by the terminal device is within the first RSRP range or the downlink path loss is within the first path loss range, the terminal device may calculate the first transmit power by using the open-loop power control calculation method. In a second case: If the first determining information indicates that the terminal device selects the current coverage level during initial random access, and the RSRP value measured by the terminal device is within the second RSRP range or the path loss is within the second path loss range, the terminal device may use the maximum transmit power of the terminal device as the first transmit power. The second RSRP range is different from the first RSRP range, and the second path loss range is different from the first path loss range. For example, the second RSRP range may be a subset of an RSRP universal set in which the first RSRP range is excluded. For example, the second path loss range may be a subset of a path loss universal set in which the first path loss range is excluded.

Alternatively, optionally, in an embodiment, that the terminal determines the first transmit power based on the first determining information and the first power control parameter includes:.

The at least one of the first power control parameters used by the terminal device to calculate the first transmit power in the case of "switching from a non-current coverage level to the current coverage level" is different from that in the case "selecting the current coverage level during initial access". The sixth RSRP range is different from the fifth RSRP range, and the sixth path loss range is different from the fifth path loss range. For example, the sixth RSRP range may be a subset of an RSRP universal set in which the fifth RSRP range is excluded. For example, the sixth path loss range may be a subset of a path loss universal set in which the fifth path loss range is excluded.

Optionally, the calculating the first transmit power by using an open-loop power control calculation method includes:.

It should be understood that the foregoing formulas are merely used as an example herein to describe a calculation manner of the open-loop power control calculation method, and there may be another possible open-loop power control calculation manner in the future. This is not limited in this embodiment of this application.

It should be further understood that, for a case below in which the first transmit power needs to be calculated by using the open-loop power control calculation method, refer to the foregoing formulas. For brevity, details are not described below.

It should be further understood that numbers "first", "second",. , and the like introduced in this embodiment of this application are merely intended to distinguish different objects, for example, distinguish different "path loss ranges", or distinguish different "RSRP ranges", and does not constitute any limitation to this embodiment of this application.

Optionally, in an embodiment, that the terminal device determines the first transmit power based on the first determining information and/or the first power control parameter includes:
determining, by the terminal device, the first transmit power based on the first power control parameter.

Specifically, the terminal device may calculate the first transmit power based on the first power control parameter.

Optionally, the first power control parameter includes the downlink path loss, and the determining, by the terminal device, the first transmit power based on the first power control parameter includes:
when the downlink path loss of the terminal device is within a seventh path loss range, calculating, by the terminal device, the first transmit power based on at least one of the first power control parameters by using an open-loop power control calculation method; or when the downlink path loss of the terminal device is within an eighth path loss range, using, by the terminal device, a maximum transmit power of the terminal device as the first transmit power. For example, the eighth path loss range may be a subset of a path loss universal set in which the seventh path loss range is excluded.

Specifically, for example, when the downlink path loss of the terminal device is greater than a first path loss threshold, the terminal device uses the maximum transmit power of the terminal device as the first transmit power; or
when the downlink path loss of the terminal device is less than or equal to the first path loss threshold, the terminal device calculates the first transmit power based on the at least one of the first power control parameters by using the open-loop power control calculation method.

Specifically, the terminal device may determine, based on a path loss, a calculation manner of the first transmit power. Specifically, the following is included: if the downlink path loss of the terminal device is greater than a threshold (for example, the first path loss threshold), the terminal device may use, by default, the maximum transmit power as the first transmit power; or if the downlink path loss of the terminal device is less than or equal to the first path loss threshold, the terminal device may calculate the first transmit power by using the open-loop power control calculation method.

For another example, when the downlink path loss of the terminal device is greater than or equal to a first path loss threshold, the terminal device uses the maximum transmit power of the terminal device as the first transmit power; or
when the downlink path loss of the terminal device is less than the first path loss threshold, the terminal device calculates the first transmit power based on the at least one of the first power control parameters by using the open-loop power control calculation method.

For another example, when the downlink path loss of the terminal device is greater than a first path loss threshold, or is equal to the first path loss threshold, or is less than the first path loss threshold, the terminal device calculates the first transmit power by using the open-loop power control calculation method. In addition, the at least one of the first power control parameters used by the terminal device to calculate the first transmit power is different in the three cases of "greater than", "equal to", and "less than".

It should be noted that the path loss ranges (including the path loss ranges with numbers) or the first path loss threshold in the foregoing embodiments may be agreed on in a protocol, or may be configured by the network device, so that the terminal device can select a calculation manner of the first transmit power based on the first path loss threshold.

Optionally, the first power control parameter includes a reference signal received power RSRP value, and the determining, by the terminal device, the first transmit power based on the first power control parameter includes:
when the reference signal received power RSRP value measured by the terminal device is within a seventh RSRP range, calculating, by the terminal device, the first transmit power based on at least one of the first power control parameters by using an open-loop power control calculation method; or when the reference signal received power RSRP value measured by the terminal device is within an eighth RSRP range, using, by the terminal device, the maximum transmit power of the terminal device as the first transmit power. The eighth RSRP range is different from the seventh RSRP range, and the eighth path loss range is different from the seventh path loss range. For example, the eighth RSRP range may be a subset of an RSRP universal set in which the seventh RSRP range is excluded.

Specifically, for example, when the reference signal received power RSRP value measured by the terminal device is greater than a first RSRP threshold, the terminal device calculates the first transmit power by using the open-loop power control calculation method, and the first RSRP threshold is notified by the network device to the terminal device; or
when the reference signal received power RSRP value measured by the terminal device is less than or equal to the first RSRP threshold, the terminal device uses the maximum transmit power of the terminal device as the first transmit power.

Specifically, the terminal device may determine a calculation manner of the first transmit power based on the reference signal received power RSRP value. Specifically, the following is included: If the reference signal received power RSRP value measured by the terminal device is greater than a threshold (for example, the first RSRP threshold), the terminal device uses, by default, the maximum transmit power as the first transmit power; or if the reference signal received power RSRP value measured by the terminal device is less than or equal to the first RSRP threshold, the terminal device may calculate the first transmit power by using the open-loop power control calculation method.

For another example, when the reference signal received power RSRP value measured by the terminal device is greater than or equal to the first RSRP threshold, the terminal device calculates the first transmit power based on at least one of the first power control parameters by using the open-loop power control calculation method, and the first RSRP threshold is notified by the network device to the terminal device; or
when the reference signal received power RSRP value measured by the terminal device is less than the first RSRP threshold, the terminal device uses the maximum transmit power of the terminal device as the first transmit power.

For another example, when the reference signal received power RSRP value measured by the terminal device is greater than the first RSRP threshold, or is equal to the first RSRP threshold, or is less than the first RSRP threshold, the terminal device calculates the first transmit power by using the open-loop power control calculation method. In addition, the at least one of the first power control parameters used by the terminal device to calculate the first transmit power is different in the three cases of "greater than", "equal to", and "less than".

It should be noted that, the RSRP ranges (including the RSRP ranges with numbers) or the first RSRP threshold in the foregoing embodiments may be specified in a protocol, or may be configured by the network device, so that the terminal device can select a calculation manner of the first transmit power based on the first RSRP threshold.

It should be understood that the foregoing description merely uses the downlink path loss and the reference signal received power RSRP value as examples. The terminal device may alternatively use another parameter in the first power control parameter as a determining condition for calculating the first transmit power, for example, whether a coverage level of the terminal device is initial access, a quantity of attempt times for sending a preamble by the terminal device. This is not limited in this embodiment of this application.

Optionally, if the terminal device uses the another parameter in the first power control parameter as the determining condition for calculating the first transmit power, the network device may indicate, to the terminal device, a critical value or a threshold of the parameter that is used, so that a power control method for the terminal device more adapts to a network feature. For example, the network device may indicate, to the terminal device, critical repetition times for sending a preamble.

Therefore, the terminal device may select or calculate a proper first transmit power based on the first power control parameter, and does not need to directly transmit an uplink signal at the maximum transmit power, thereby reducing interference to uplink transmission of another terminal device.

Optionally, in an embodiment, that the terminal device determines the first transmit power based on the first determining information and/or the first power control parameter includes:
determining, by the terminal device, the first transmit power based on the first determining information.

Specifically, the terminal device may determine the first transmit power based on the first determining information.

Optionally, the determining, by the terminal device, the first transmit power based on the first determining information includes:
when the first determining information indicates that the terminal device selects the current coverage level during initial random access, using, by the terminal device, the maximum transmit power of the terminal device as the first transmit power.

Specifically, if the first determining information indicates that the terminal device selects the current coverage level during initial random access, the terminal device may use, by default, the maximum transmit power of the terminal device as the first transmit power.

For example, assuming that the first determining information indicates that the terminal device selects a coverage level <NUM> during initial random access, the terminal device may transmit, by default, a signal based on the maximum transmit power of the terminal device. Alternatively, assuming that the first determining information indicates that the terminal device selects a coverage level <NUM> during initial random access, the terminal device may transmit, by default, a signal based on the maximum transmit power of the terminal device.

Therefore, after determining is completed based on the first determining information, the terminal device may determine whether to use the maximum transmit power as the first transmit power, so that the terminal device does not directly use the maximum transmit power to transmit an uplink signal, thereby reducing interference to uplink transmission of another terminal device.

The following describes the method according to this embodiment of this application from a network device side. For brevity, terms or concepts similar to those on a terminal device side are not described again. <FIG> is a schematic flowchart of a signal transmission method <NUM> according to an embodiment of this application. The method <NUM> may be performed by a network device. For example, the network device may be the base station <NUM> in <FIG>. Correspondingly, a terminal device that communicates with the network device may be the terminal device <NUM>, the terminal device <NUM>, or the terminal device <NUM> in <FIG>. As shown in <FIG>, the method <NUM> includes the following steps:.

The network device sends first indication information to the terminal device, where the first indication information is used to indicate at least one of first power control parameters.

The network device receives a signal transmitted by the terminal device at a first transmit power, where the first transmit power is determined by the terminal device based on an access status of the terminal device at a current coverage level and/or the first power control parameter.

Optionally, the first indication information may indicate some parameters in the first power control parameters.

Optionally, the terminal device may obtain the first power control parameter independently, in other words, the terminal device may not rely on the parameters indicated by the first indication information.

Optionally, the first power control parameter includes at least one of the following parameters:
reference signal received power RSRP, a downlink path loss, a transmission bandwidth parameter, a maximum transmit power of the terminal device, a preamble target received power, an initial preamble target received power, an initial transmit power, a preamble power offset, a quantity of preamble attempts, a power ramping step, a path loss conversion proportional coefficient, repetition times for sending a preamble, and a power indication parameter.

It should be understood that in this embodiment of this application, sequence numbers of the foregoing processes do not mean execution sequences. The execution sequences of the processes should be determined based on functions and internal logic of the processes, and should not constitute any limitation to implementation processes in this embodiment of this application.

In other words, in this embodiment of this application, an operation sequence of S310 and S320 is not limited.

The foregoing describes the signal transmission method according to this embodiment of this application. The following describes a terminal device according to an embodiment of this application.

<FIG> is a schematic block diagram of a terminal device <NUM> according to an embodiment of this application. As shown in <FIG>, the terminal device <NUM> includes:.

In this embodiment of this application, the terminal device <NUM> may determine the first transmit power based on the access status of the terminal device at the current coverage level and/or the first power control parameter, and transmit the signal at the first transmit power, so as to reduce interference between terminal devices.

Optionally, the determining module <NUM> is configured to determine the first transmit power based on the first determining information and the first power control parameter.

Optionally, the determining module <NUM> is specifically configured to:.

Therefore, the terminal device <NUM> may select or calculate a proper first transmit power based on the first determining information and the first power control parameter, and does not need to directly transmit an uplink signal at the maximum transmit power, thereby reducing interference to uplink transmission of another terminal device.

Optionally, the determining module <NUM> is configured to determine the first transmit power based on the first power control parameter.

Optionally, the first power control parameter includes the downlink path loss, and the determining module <NUM> is specifically configured to:.

Optionally, the first power control parameter includes a reference signal received power RSRP value, and the second determining module <NUM> is specifically configured to:.

Therefore, the terminal device <NUM> may select or calculate a proper first transmit power based on the first power control parameter, and does not need to directly transmit an uplink signal at the maximum transmit power, thereby reducing interference to uplink transmission of another terminal device.

Optionally, the determining module <NUM> is configured to determine the first transmit power based on the first determining information.

Optionally, the determining module <NUM> is specifically configured to:
when the first determining information indicates that the terminal device selects the current coverage level during initial random access, use the maximum transmit power of the terminal device as the first transmit power.

Therefore, after determining is performed based on the first determining information, the terminal device <NUM> may determine whether to use the maximum transmit power as the first transmit power, so that the terminal device does not directly use the maximum transmit power to transmit an uplink signal, thereby reducing interference to uplink transmission of another terminal device.

Optionally, the open-loop power control calculation method meets the following formulas: <MAT> and <MAT> where
PNPRACH represents the first transmit power; PCMAX ,c(i) represents the maximum transmit power of the terminal device; c is a cell number; i is a subframe number; PPRT represents a preamble target received power; PLc represents a downlink path loss value, obtained by the terminal device through measurement, of the cell c; PPIRT represents an initial preamble target received power; PDP represents a preamble power offset; NP<NUM> represents a quantity of preamble attempts; Ps represents a power ramping step; and NP<NUM> represents a quantity of repetition times for currently sending a preamble.

According to this embodiment of this application, the terminal device <NUM> may perform the method on the terminal device side in the signal transmission method in the embodiments of this application. The foregoing and other operations and/or functions of the modules or units in the terminal device <NUM> are separately used to implement corresponding procedures of the method. For brevity, details are not described herein.

Therefore, in this embodiment of this application, the terminal device <NUM> may determine the first transmit power based on the first determining information and/or the first power control parameter, and transmit the signal at the first transmit power, so as to reduce interference between terminal devices.

<FIG> is a schematic block diagram of a network device <NUM> according to an embodiment of this application. As shown in <FIG>, the network device <NUM> includes:.

According to this embodiment of this application, the network device <NUM> may perform the method on the network device side in the signal transmission method in the embodiments of this application. The foregoing and other operations and/or functions of the modules in the network device <NUM> are separately used to implement corresponding procedures of the methods. For brevity, details are not described herein.

In this embodiment of this application, the network device <NUM> receives the signal transmitted by the terminal device at the first transmit power, and the first transmit power is determined by the terminal device based on the access status of the terminal device at the current coverage level and/or the first power control parameter, thereby reducing interference between terminal devices.

<FIG> shows a structure of a terminal device according to an embodiment of this application. The terminal device includes at least one processor <NUM> (for example, a CPU), at least one network interface <NUM> or another communications interface, and a memory <NUM>. Optionally, the terminal device may further include a receiver <NUM> and a transmitter <NUM>. The processor <NUM> is configured to execute an executable module, such as a computer program, that is stored in the memory <NUM>. The memory <NUM> may include a high-speed random access memory RAM, and may also further include a non-volatile memory (non-volatile memory), for example, at least one magnetic disk storage. The at least one network interface <NUM> (which may be wired or wireless) is configured to implement a communications connection to at least one another network element. The receiver <NUM> and the transmitter <NUM> are configured to transmit various signals or information.

In some implementations, the memory <NUM> stores a program <NUM>, and the program <NUM> may be executed by the processor <NUM>, to perform the method on the terminal device side in the foregoing another embodiment of this application.

<FIG> shows a structure of a network device according to an embodiment of this application. The network device includes at least one processor <NUM> (for example, a CPU), at least one network interface <NUM> or another communications interface, and a memory <NUM>. Optionally, the network device may further include a receiver <NUM> and a transmitter <NUM>. The processor <NUM> is configured to execute an executable module, such as a computer program, that is stored in the memory <NUM>. The memory <NUM> may include a high-speed random access memory RAM, and may also include a non-volatile memory (non-volatile memory), for example, at least one magnetic disk storage. The at least one network interface <NUM> (which may be wired or wireless) is configured to implement a communications connection to at least one another network element. The receiver <NUM> and the transmitter <NUM> are configured to transmit various signals or information.

In some implementations, the memory <NUM> stores a program <NUM>. The program <NUM> may be executed by the processor <NUM>, and is used to perform the method on the network device side in the foregoing embodiment of this application.

It should be further understood that in the embodiments of this application, sequence numbers of the foregoing processes do not mean execution sequences. The execution sequences of the processes should be determined based on functions and internal logic of the processes, and should not constitute any limitation to implementation processes in the embodiments of this application.

A person of ordinary skill in the art may be aware that units and algorithm steps in the examples described with reference to the embodiments disclosed in this specification can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on a particular application and a design constraint condition of a technical solution. For specific applications, a person skilled in the art may use different methods to implement the described functions; however, this implementation should not be construed as going beyond the scope of the embodiments of this application.

It may be clearly understood by a person skilled in the art that, for convenience and brevity of description, for specific working processes of the system, apparatus, and unit described above, refer to corresponding processes in the foregoing method embodiments.

For example, the unit division is merely logical function division and may be other division in an actual implementation. In addition, displayed or discussed mutual couplings or direct couplings or communication connections may be implemented by using some interfaces. The indirect couplings or communication connections between the apparatuses or units may be implemented in electronically, mechanically, or in another form.

The units described as separate parts may or may not be physically separate; and parts displayed as units may or may not be physical units, in other words, may be located in one position, or may be distributed on a plurality of network units. Some or all of the units may be selected based on actual requirements to achieve the objectives of the solutions in the embodiments.

When the functions are implemented in a form of a software function unit and sold or used as an independent product, the functions may be stored in a computer-readable storage medium. Based on such an understanding, the technical solutions of the embodiments in this application essentially, or the part contributing to the prior art, or some of the technical solutions may be embodied in a form of a software product. The computer software product is stored in a storage medium, and includes several instructions for instructing a computer device (which may be a personal computer, a server, a network device, or the like) to perform all or some of the steps of the methods described in the embodiments of this application. The foregoing storage medium includes: various media that can store program code, such as a USB flash drive, a removable hard disk, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk, and an optical disc.

Claim 1:
A signal transmission method, comprising:
determining (S210), by a terminal device (<NUM>), a transmit power less than the maximum transmit power of the terminal device based on an access status of the terminal device at a current coverage level and a power control parameter; and
transmitting (S220), by the terminal device (<NUM>), a signal at the transmit power;
wherein the power control parameter comprises at least one of a downlink path loss and a reference signal received power, RSRP; and
wherein the determining, by the terminal device (<NUM>), the transmit power based on an access status of the terminal device (<NUM>) at a current coverage level and a power control parameter comprises:
when the power control parameter comprises the downlink path loss and when the downlink path loss of the terminal device (<NUM>) is less than or equal to a path loss threshold, calculating, by the terminal device (<NUM>), the transmit power by using an open-loop power control calculation method;
or
when the terminal device (<NUM>) is switched from a non-current coverage level to the current coverage level, and an RSRP value measured by the terminal device (<NUM>) is within a first RSRP range or a path loss measured by the terminal device (<NUM>) is within a first path loss range, calculating, by the terminal device (<NUM>), the transmit power by using an open-loop power control method.