CN109845339B

CN109845339B - Method and device for transmitting signals

Info

Publication number: CN109845339B
Application number: CN201880003385.3A
Authority: CN
Inventors: 许华
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2017-01-27
Filing date: 2018-01-16
Publication date: 2020-03-03
Anticipated expiration: 2038-01-16
Also published as: WO2018137516A1; TW201828755A; CN109845339A; TWI698142B

Abstract

A method and apparatus for transmitting a signal are provided. In the design of the 1-port demodulation reference signal, two resource elements in the resource element set are used for the demodulation reference signal, and the rest resource elements are used for the physical downlink control channel. Optionally, two resource elements in the resource element set are used for demodulating the reference signal, two null resource elements are used for power boosting, and the remaining resource elements are used for the physical downlink control channel.

Description

Method and device for transmitting signals

This application claims priority to U.S. provisional application 62/451,266 filed on 27.01.2017, the entire contents of which are incorporated herein by reference.

Technical Field

The present invention relates to the field of communications, and in particular, to a method and apparatus for transmitting signals.

Background

In Long Term Evolution (LTE) R8(Rel-8) version, a cell-specific reference signal (CRS) is used for Physical Downlink Control Channel (PDCCH) demodulation, and the number of CRS ports is cell-specific. In lte 11(Rel-11) version, one antenna port (1-port for short) demodulation reference signal (DMRS) is dedicated for localized Enhanced PDCCH (EPDCCH) demodulation, and two antenna port (2-port for short) DMRS is dedicated for distributed EPDCCH demodulation.

In a 5G New Radio (NR) system, DMRS can be used for PDCCH decoding, and accordingly, a new NR PDCCH DMRS design is required to accommodate the requirement of 5G NR.

Disclosure of Invention

In the present invention, DMRS is used for PDCCH decoding, and some DMRS designs are proposed for 5G NR PDCCH, such as DMRS with one antenna port (1-port DMRS for short) and DMRS with two antenna ports (2-port DMRS for short). In addition, User Equipment (UE) specific DMRS port configurations are also proposed.

In one embodiment, the technology herein includes providing a method of transmitting a signal. In this method, a 1-port DMRS for NRPDCCH may use two REs in a resource element set (RE set) for DMRSs and the remaining REs for PDCCH.

In one embodiment, the technology herein includes providing a method of transmitting a signal. In this method, a 1-port DMRS for NRPDCCH may use four REs in a resource element set for DMRSs and the remaining REs for PDCCH.

In one embodiment, the technology herein includes providing a method of transmitting a signal. In the method, two REs in a resource element set are used for DMRS, two null (null) REs are configured in the resource element set, and the remaining REs in the resource element set are used for PDCCH.

In one embodiment, the technology herein includes providing a method of transmitting a signal. In this method, a 2-port DMRS for NRPDCCH may use four REs in a resource element set for DMRSs and the remaining REs for PDCCH.

Drawings

The invention will be better understood from the following description taken in conjunction with the accompanying drawings. In the drawings:

fig. 1 shows a wireless communication system.

Fig. 2 shows a terminal.

Fig. 3 illustrates a network device.

Fig. 4 shows PDCCH CRS design for LTE.

Fig. 5 shows PDCCH 1-port DMRS design for 5G NR according to an embodiment of the present invention.

Fig. 6 shows another PDCCH 1-port DMRS design for 5G NR according to an embodiment of the present invention.

Fig. 7 shows yet another PDCCH 1-port DMRS design for 5G NR in accordance with an embodiment of the present invention.

Fig. 8 shows yet another PDCCH 1-port DMRS design for 5G NR in accordance with an embodiment of the present invention.

Fig. 9 shows PDCCH 2-port DMRS design for 5G NR according to an embodiment of the present invention.

Fig. 10 is a block diagram of an apparatus for transmitting a signal according to an embodiment of the present invention.

Fig. 11 is a block diagram of an apparatus according to an embodiment of the present invention.

Detailed Description

Fig. 1 illustrates a wireless communication system 100 in accordance with an embodiment of the present invention. The wireless communication system 100 shown in fig. 1 may operate in a high frequency band, which includes, but is not limited to, a Long Term Evolution (LTE) system, a fifth generation (5G) system for future evolution, a New Radio (NR) system, and a machine to machine (M2M) system. The wireless communication system 100 shown in fig. 1 is only an example of the technical solution of the embodiment of the present invention, and is not used to limit the scope of the embodiment of the present invention. It will be appreciated by those of ordinary skill in the art that as network architectures evolve and new business scenarios emerge, the solutions presented herein may be equally applicable to solving similar technical problems.

As shown in fig. 1, a wireless communication system 100 may include one or more network devices 101, one or more terminals 103, and a core network 111.

Network device 101 may be a base station that may communicate with one or more terminals or with a base station having terminal capabilities. In a 5G NR system, the base station may be a gNB (G-Node B). Terminals 103 may be distributed in the wireless communication system 100. The terminal 103 may be fixed or mobile. In some embodiments, terminal 103 may be a mobile device, mobile station, mobile unit, M2M terminal, wireless unit, remote unit, user agent, mobile client, or the like. The network device 101 may communicate with the terminal 103 under the control of a controller (not shown in the figure). In some embodiments, the controller may be part of the core network 111 or may be integrated into the network device 101. The network devices 101 may also communicate with each other directly or indirectly through a backhaul interface 107, such as an X2 interface. The network device 101 may be used to transmit control information or user data to the core network 111 through a backhaul interface 109, such as an S1 interface. A terminal 103 may be located within the coverage of one or more cells 105.

Fig. 2 shows a terminal 200. The terminal 200 may include one or more terminal processors 201, memory 202, a communication interface 203, a bus 204, a receiver 205, a transmitter 206, a coupler 207, an antenna 208, a user interface 209, and input/output devices (e.g., microphone, keypad, display, etc.). The processor 201, communication interface 203, receiver 205, and transmitter 206 may be connected by a bus 204 or otherwise. The terminal 200 can communicate with other communication devices such as network devices through the communication interface 203. Transmitter 206 may be used to transmit signals output from terminal processor 201. Input/output devices 210 may be used to enable interaction between terminal 200 and a user/external environment. Memory 202 and terminal processor 201 are used to store various software programs and/or instructions. Terminal processor 201 may be configured to read and execute computer readable instructions, such as stored in memory 202.

Fig. 3 shows a network device 300. Network device 300 may be a gbb. Network device 300 may include one or more network device processors 301, memory 302, communication interface 303, transmitter 305, receiver 306. The above components may be connected by a bus 304 or other means. As shown in fig. 3, the network device 300 may also include a coupler 307 and an antenna 308 connected to the coupler. The communication interface 303 may be used for the network device 300 to communicate with other communication devices, such as terminal devices or other network devices. The transmitter 305 may be used to transmit signals from the network device processor 301, such as for signal modulation. The network device processor 301 may be responsible for radio channel management, communication link establishment, and cell switching control for users within a control area, among other things. The network device processor 301 is operable to read computer readable instructions, such as stored in a memory 302, the memory 302 being coupled to the network device processor 301.

Between the network device and the terminal, the PDCCH is typically used to carry scheduling and other control information, including transport format, resource allocation, uplink scheduling grants, power control, and uplink retransmission information. A Physical Downlink Shared Channel (PDSCH) is used as a downlink channel and is generally used for carrying user data.

Fig. 4 shows a PDCCH cell-specific reference signal (CRS) design in LTE. As shown in fig. 4, in the LTE system, the PDCCH is transmitted on the first several Orthogonal Frequency Division Multiplexing (OFDM) symbols across the entire system bandwidth located at the beginning of a subframe. As can be seen from fig. 4, the time length of the PDCCH may be three symbols, for example. One Physical Resource Block (PRB) occupies twelve subcarriers in the frequency domain. Two REs in one resource element set may be used for CRS port #0, and the other two REs may be used for CRS port # 1.

CRS is used to demodulate PDCCH and support 1-port CRS, 2-port CRS, and 4-port CRS, where "port" refers to "antenna port". In LTE systems, CRS ports are cell-specific, and therefore, do not change based on a single User Equipment (UE). In LTE R11 release, 1-port DMRS is dedicated for localized EPDCCH demodulation and 2-port DMRS is dedicated for distributed EPDCCH demodulation.

In a 5G NR system, DMRSs may be used for PDCCH decoding and may support 1-port DMRSs and 2-port DMRSs. Techniques provided by the present invention include 1-port and 2-port DMRS designs for 5G NR and UE-specific DMRS port configurations, which can accommodate requirements in 5G NR systems. The technical scheme of the embodiment of the invention can be used for transmitting signals and the like.

Since DMRS is used for PDCCH and may be embedded and transmitted in PRB carrying PDCCH, the number of DMRS ports may be UE specific and may be semi-statically configured on a UE basis and by using higher layer signaling. For example, if a UE is in the center of a cell, and thus does not require transmit diversity to improve its PDCCH performance, the UE may be configured with a 1-port DMRS, and the exemplary DMRS designs shown in any of fig. 5-8 may be used for PDCCH demodulation for the UE. For another UE located at the cell edge, which may need transmit diversity to improve its PDCCH performance or increase its PDCCH performance/coverage, a 2-port DMRS may be configured for the UE and the exemplary design shown in fig. 9 may be used.

A "resource" as referred to herein is a time-frequency resource, including both time-domain resources and frequency-domain resources. The form of a resource may be, but is not limited to, Resource Element (RE), Resource Block (RB), symbol, carrier (subcarrier), Transmission Time Interval (TTI), and the like. The definition of concepts such as resource particles, resource blocks, etc. can refer to the LTE standard. The embodiments of the present invention are not limited to the LTE standard. The definitions of the various resource forms involved in the embodiments of the present application may vary in future communication standards, but this does not affect the essence of the present invention. In the following description, a Physical Resource Block (PRB) and an RE are taken as an example for explanation. It should be noted that the terms and phrases used herein are exemplary only and are not intended to limit the present invention in any manner.

PRB: a PRB is a time-frequency resource that occupies twelve subcarriers in the frequency domain and fourteen OFDM symbols (i.e., two slots) in the time domain.

RE is a time-frequency resource that occupies one subcarrier in the frequency domain and one OFDM symbol in the time domain. One PRB consists of twelve REs.

In one embodiment, the number of ports for DMRS for NR PDCCH may be semi-statically configured on a per UE basis, e.g., through higher layer signaling. For example, DMRS port configuration for NR PDCCH may be performed in combination with DMRS port configuration for PDSCH, or may be performed separately. Specifically, DMRS port configuration for Downlink (DL) PDCCH may be performed in combination with DMRS configuration for data (which may be transmitted on PDSCH). For example, both PDCCH and PDSCH may be configured with 1-port DMRSs, although DMRS port indices for PDCCH and PDSCH may differ depending on the pattern and density of DMRSs. Alternatively, the number of DMRS ports for PDCCH may be configured as one port, and the number of DMRS ports for PDSCH may be configured as two to eight ports, which is not limited in the present invention.

The 1-port DMRS design and the 2-port DMRS design for PDCCH will be described in detail below.

1-Port DMRS designs for 5G NR systems

Example 1

Fig. 5 shows a 1-port DMRS design for PDCCH. In the illustrated example, two REs in one resource element set may be used for DMRS (dark blocks in fig. 5, hereinafter, simply referred to as "REs for DMRS"), and the remaining ten REs are used for PDCCH (light blocks in fig. 5, hereinafter, simply referred to as "REs for PDCCH"). Accordingly, in the method for transmitting a signal, the DMRS is transmitted using two REs in the resource element set, and the PDCCH is transmitted using the remaining ten REs in the PRB. "resource element set" refers to resource elements in a PRB of an OFDM symbol.

The positions of two REs for DMRS, in other words, the number of REs for PDCCH between two REs for DMRS, may be flexibly configured. In the example shown in fig. 5, between two REs for DMRS, there are an even number (i.e., six) of REs for PDCCH; whereas in fig. 6, between two REs for DMRS, there are an odd number (i.e., three) REs for PDCCH. Any other similar configuration may be employed, as the present invention is not limited in this regard. As an embodiment, the location of the RE for the DMRS may consider DMRS density, channel estimation gap, and the like. In consideration of channel response, REs for DMRS in a resource element set (in other words, physical resource blocks) may be uniformly or discretely distributed on a PRB to obtain a more accurate channel estimation result at the PRB.

Compared to the LTE CRS design shown in fig. 4, the 1-port DMRS design for PDCCH shown in fig. 5 or fig. 6 may provide similar frequency gap/density as LTE, and thus, can provide similar channel estimation performance as LTE.

Example 2

Fig. 7 shows another 1-port DMRS design for PDCCH. In this design, based on the DMRS design of fig. 5, two null REs are created (i.e., used) in the resource element set for power boosting. Null REs refer to REs used for neither DMRS nor PDCCH. As shown in fig. 7, the null REs (blank blocks in fig. 7) may be adjacent to REs for DMRSs (deep color blocks in fig. 7), e.g., the null REs may be located on the left or right side of the REs for DMRSs. In this case, eight REs (light color blocks in fig. 7) are left for PDCCH. Accordingly, in the method for transmitting a signal, two REs in the resource element set are used for transmitting DMRS, two null REs are used for power boosting, and the remaining eight REs in the resource element set are used for PDCCH transmission.

Example 3

Alternatively, fig. 8 shows another 1-port DMRS design for PDCCH, where four REs in a resource element set may be used for DMRS and the remaining REs may be used for PDCCH. As shown in fig. 8, the four dark REs in the PRB may all be used to carry the 1-port DMRS, and thus the same power boosting effect as that of fig. 7 may be achieved. The four REs for DMRS may be divided into two pairs, each pair including two adjacent REs, to achieve multiplexing and to obtain diversity gain. On the top reference signal transmitted on each pair of adjacent REs, an orthogonal cover code may be added, which may mitigate the interference from DMRSs of other cells (assuming they use the same RE pair).

Compared to the design of fig. 5 or fig. 6, although this variation of fig. 7 or fig. 8 reduces the number of REs used for PDCCH in a resource element set from ten to eight, since DMRS can borrow power from empty REs or adjacent REs, power boosting can also be achieved, and thus channel estimation accuracy can be improved.

2-Port DMRS designs for 5G NR systems

Fig. 9 shows an example of a 2-port DMRS for a PDCCH. Wherein, in the resource element set, two pairs of REs (dark color blocks in fig. 9) are used for DMRS, and the remaining eight REs are used for PDCCH. Wherein each pair of REs comprises two adjacent REs.

For each pair of REs used for DMRS, Frequency Division Multiplexing (FDM) or Code Division Multiplexing (CDM) may be applied to obtain a 2-port DMRS. The density and spacing between each pair of REs will allow for channel estimation. In this 2-port DMRS design, convenience of applying transmit diversity, such as space-frequency block code (SFBC), is also considered for the location of REs, in addition to DMRS density and gap for channel estimation, as compared to the case of 1-port DMRS. Based on this, as shown in fig. 9, between two pairs of REs for DMRS, there may be an even number of REs for PDCCH.

Similarly, the number of DMRS ports for NR PDCCH may be semi-statically configured on a per UE basis, i.e., configured by higher layer signaling or signals. The number of DMRS ports for NR PDCCH may be configured in conjunction with DMRS port configuration for PDSCH, or may be separately configured.

Compared to the LTE CRS design shown in fig. 4, the 2-port DMRS design for PDCCH shown in fig. 9 may provide similar frequency gap/density as LTE, and in turn may provide similar channel estimation performance as LTE.

Unified design

The 1-port DMRS configurations shown in fig. 7 and 8 may result in the same RE mapping as the 2-port DMRS configuration shown in fig. 9, and thus, the same number of REs may be configured for a PDCCH in each PRB (also referred to as a Resource Element Group (REG) or resource element set for the PDCCH) without considering the number of DMRS antenna ports, which may more facilitate uniform design of the PDCCH. In other words, eight REs are configured for PDCCH regardless of 1-port DMRS or 2-port DMRS.

Device

According to an embodiment of the invention, there is also provided an apparatus for transmitting a signal. In particular embodiments, the device may use the DMRS design described above and may be configured to perform the method of transmitting signals described above.

Fig. 10 is a block diagram illustrating an apparatus for transmitting a signal. As shown in fig. 10, the apparatus 40 may include a configuration unit 42 and a transmission unit 44. The device 40 may be configured on the gbb side and may communicate with user equipment. The configuration unit 42 may be a processor integrated with resource configuration functionality. The transmission unit 44 may be a transmitter, a receiver, an antenna, a wireless transmission device, or any other device integrated with a transmission function.

In the process of transmitting signals, the configuration unit 42 may be configured to configure resources for carrying DMRSs, where the resources for carrying DMRSs are two REs or four REs for 1-port DMRSs or 2-port DMRSs. The configuration of the resources may be based on at least one of DMRS density, channel estimation gap, transmission diversity.

Specifically, for a 1-port DMRS, the resources configured for the DMRS may be two REs or four REs. In case of two REs, the two REs may be uniformly or discretely distributed over the PRB to obtain a more accurate channel estimation result of the PRB. In the case of four REs, the configuration may allocate the four REs as two pairs of REs, where each pair of REs includes two adjacent REs. For a 2-port DMRS, the resources configured for the DMRS are four REs, and the four REs may be allocated as two pairs of REs, wherein each pair of REs includes two adjacent REs, similar to the case of a 1-port DMRS, to achieve multiplexing and diversity gains.

As an embodiment, in the case that the resource configured for the 1-port DMRS is two REs, the configuration unit 42 may further be configured to configure two null REs to achieve power boosting. Each of the two null REs is adjacent to one of two REs for DMRS, respectively, and an even number of REs for PDCCH may be spaced between the two null REs. Details of this configuration can be found in the above description and in fig. 7.

In the process of transmitting signals, the transmission unit 44 may be configured to transmit the DMRS on the resource configured by the configuration unit 42.

The details described in the above method embodiments are also applicable to this apparatus embodiment and will not be described here again.

Certain aspects of the embodiments described herein may be implemented as a computer program product or software. In particular, but not limited to, a computer-readable storage medium or a non-volatile machine-readable medium having instructions stored thereon. The instructions may be used to program a computer system (or other electronic devices) or processor to perform a process according to the present invention. A non-transitory machine-readable medium includes any mechanism for storing information in a form (e.g., software, processing application) readable by a machine (e.g., a computer). Forms of non-volatile machine-readable media include, but are not limited to, magnetic storage media, optical storage media (e.g., CD-ROM), magneto-optical storage media, Read Only Memory (ROM), Random Access Memory (RAM), erasable programmable memory, flash memory, and the like.

Based on this, fig. 11 shows a device 50, which device 50 has a processor 52 and one or more interfaces 56 connected with the processor 52 via a bus 54. The interface 56 may be, for example, a general purpose input/output (GPIO) interface.

Processor 52 may be used to read and execute computer readable instructions. In one embodiment, the processor 52 may primarily include a controller, an operator, and registers. The hardware architecture of the processor 52 may be an Application Specific Integrated Circuit (ASIC) architecture, a microprocessor with interlocked pipeline stages (MIPS) architecture without internal interlocking, a Reduced Instruction Set Computer (RISC) machine (ARM) architecture, or a Network Processor (NP) architecture.

The interface 56 may be used to input data to be processed to the processor 52 and/or output a processing result of the processor 52 to the outside. The interface 56 may interface with one or more peripheral devices such as a display, a camera, a radio frequency module, and the like.

In conjunction with the technical solution of the present invention, the processor 52 may call a program for a method of transmitting a signal from the memory, and execute instructions included in the program to implement corresponding operations, such as resource configuration. The interface 56 may be used to output the results of the resource configuration so that the transceiver can transmit signals on the configured resources.

By means of the technical scheme described in the embodiment of the invention, a new NR PDCCH DMRS design is provided to meet the requirements of a 5G NR system.

Although the present invention has been described with reference to specific features and embodiments thereof, it will be understood that the above embodiments are merely examples and the scope of the present invention is not limited thereto. Various alterations, modifications, additions, and improvements may be made to the embodiments of the invention. The above-described functions may be separated or combined in different programs, or described using different terminology in different embodiments of the present invention.

Claims

1. A method for transmitting signals is applied to a 5G NR system and comprises the following steps:

transmitting a demodulation reference signal for a physical downlink control channel using two resource elements in a resource element set, wherein the demodulation reference signal is a 1-port demodulation reference signal, and the resource element set is a resource element in a physical resource block of an orthogonal frequency division multiplexing symbol;

configuring two null resource elements in the resource element set; each of the two null resource elements is adjacent to one of the two resource elements for transmitting the demodulation reference signal, respectively.

2. The method of claim 1, wherein an even number of resource elements for transmitting a physical downlink channel are inserted between the two null resource elements.

3. The method of claim 1, further comprising:

transmitting a physical downlink channel using remaining resource elements in the set of resource elements, wherein the remaining resource elements include resource elements in the set of resource elements excluding the two resource elements used for transmitting demodulation reference signals and the two empty resource elements.

4. The method according to any of claims 1-3, wherein the configuration of the resource elements for transmission of demodulation reference signals is configured based on a user equipment.

5. The method according to any of claims 1-3, wherein the configuration of the resource elements for transmission of demodulation reference signals is configured by higher layer signaling.

6. The method of any one of claims 1-3, wherein a number of ports for the DMRS of the PDCCH is configured based on the user equipment and via higher layer signaling.

7. The method of claim 6, wherein a number of ports for the DMRS of the PDCCH is configured in conjunction with a demodulation reference signal port configuration for a physical downlink shared channel.

8. A method for transmitting signals is applied to a 5G NR system and comprises the following steps:

transmitting a demodulation reference signal for a physical downlink channel using four resource elements in a resource element set, the resource element set being resource elements in a physical resource block of an orthogonal frequency division multiplexing symbol;

the four resource elements for transmitting the demodulation reference signal are divided into two pairs of resource elements by an even number of resource elements for transmitting a physical downlink channel, wherein each pair of resource elements has two adjacent resource elements.

9. The method of claim 8, wherein the configuration of the resource elements for transmission of demodulation reference signals is configured based on user equipment and via higher layer signaling.

10. The method of claim 8, wherein a number of ports for the DMRS of the PDCCH is configured based on a user equipment and via higher layer signaling.

11. The method of claim 10, wherein a number of ports for the DMRS of the PDCCH is configured in conjunction with a demodulation reference signal port configuration for a physical downlink shared channel.

12. The method of any of claims 8-11, wherein the demodulation-reference signal is a 1-port demodulation-reference signal.

13. The method of any of claims 8-11, wherein the demodulation-reference signal is a 2-port demodulation-reference signal.

14. An apparatus for transmitting a signal, comprising:

a configuration unit, configured to configure a resource for carrying a demodulation reference signal, where the resource for carrying the demodulation reference signal is two or four resource elements in a resource element set for a 1-port demodulation reference signal or a 2-port demodulation reference signal; and

a transmission unit, configured to transmit a demodulation reference signal on the configured resource;

the configuration unit is further configured to configure two null resource elements when the configured resource is two resource elements for transmitting a 1-port demodulation reference signal; each of the two null resource elements is adjacent to one of the two resource elements for transmitting a demodulation reference signal;

15. The apparatus of claim 14, wherein each of the two null resource elements is separated by an even number of resource elements used for transmission of a physical downlink channel.

16. An apparatus comprising a processor and a memory connected to the processor and storing instructions that, when executed by the processor, cause the processor to perform the method of transmitting a signal according to any one of claims 1-7.

17. An apparatus comprising a processor and a memory connected to the processor and storing instructions that, when executed by the processor, cause the processor to perform the method of transmitting a signal according to any one of claims 8-13.

18. A computer-readable storage medium storing instructions that, when executed by a computer, cause the computer to perform the method of transmitting a signal according to any one of claims 1-7.

19. A computer-readable storage medium storing instructions that, when executed by a computer, cause the computer to perform the method of transmitting a signal according to any one of claims 8-13.