GB2583524A - Improvements in and relating to Doppler compensation in a non-terrestrial telecommunication network - Google Patents
Improvements in and relating to Doppler compensation in a non-terrestrial telecommunication network Download PDFInfo
- Publication number
- GB2583524A GB2583524A GB1906237.1A GB201906237A GB2583524A GB 2583524 A GB2583524 A GB 2583524A GB 201906237 A GB201906237 A GB 201906237A GB 2583524 A GB2583524 A GB 2583524A
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- doppler shift
- base station
- gnb
- shift information
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- 230000005540 biological transmission Effects 0.000 claims abstract description 13
- 230000004044 response Effects 0.000 claims abstract description 12
- 101100274486 Mus musculus Cited2 gene Proteins 0.000 claims abstract description 8
- 101150096622 Smr2 gene Proteins 0.000 claims abstract description 8
- 101100533725 Mus musculus Smr3a gene Proteins 0.000 claims abstract description 5
- 238000000034 method Methods 0.000 claims description 24
- 230000011664 signaling Effects 0.000 claims description 8
- 230000000694 effects Effects 0.000 description 6
- 230000008569 process Effects 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 2
- 238000003491 array Methods 0.000 description 1
- 238000005311 autocorrelation function Methods 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002085 persistent effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
- H04B7/18513—Transmission in a satellite or space-based system
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1853—Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W56/00—Synchronisation arrangements
- H04W56/0035—Synchronisation arrangements detecting errors in frequency or phase
Abstract
Compensating for Doppler shift in a telecommunication network comprising a terrestrial User Equipment, UE, and a base station, gNB, at a satellite. The base station, gNB 20, estimates Doppler shift information S100, transmits the Doppler shift information to the UE 10 S110, and the UE 10 adjusts a transmission frequency to transmit to the base station on the basis of the received Doppler shift information S120. The base station, gNB, may comprise a Doppler shift estimator operable to estimate Doppler shift on the basis of one or more inputs including: gNB position, gNB spot beam coverage, gNB spot beam pattern, gNB velocity and UE signal. The Doppler shift information may be included in a System Information Block, SIB, transmission or in a Random Access response message, Msg2, in response to the base station receiving a Random Access message, Msg1, from the UE.
Description
Improvements in and relating to Doppler compensation in a non-terrestrial telecommunication network The present invention relates to improved techniques to compensate for Doppler shift experienced in a non-terrestrial network (NTN). Such an NTN may take the form of a Fifth Generation (5G) or New Radio network, where a base station is deployed at a satellite.
In 5G or NR systems, it is possible to deploy a high-altitude platform station (HAPS) and satellite nodes in NR can be important components of a 5G system. The deployment of non-terrestrial networks (NTNs) is highly different from that of terrestrial networks, which can cause impacts on standard specifications. In particular, in prior art telecommunication systems, Doppler effect is less significant in ordinary terrestrial communications. However, as NR is intending to include provision for NTNs, significant Doppler effects can occur when NR base station (gNB) is at a satellite side.
In NR NTN, the Doppler Effect due to the fast relative movement between a NTN gNB, e.g., gNB on a Low Earth Orbit (LEO) satellite, and a User Equipment (UE), which can be more than 7km per second and more than 20 ppm Doppler shift for a 2 GHz carrier frequency. A high Doppler shift can significantly degrade the decoding performance.
Embodiments of the present invention aim to address issues in the prior art whether mentioned herein or not. In particular, embodiments aim to compensate for Doppler effects in the scenarios mentioned.
According to a first aspect of the present invention, there is provided a method of compensating for Doppler shift in a telecommunication network comprising a terrestrial User Equipment, UE, and a base station, gNB, at a satellite, comprising the steps of: the base station estimating Doppler shift information; the base station transmitting the Doppler shift information to the UE; the UE adjusting a transmission frequency to transmit to the base station.
In an embodiment, the step of the base station transmitting the Doppler shift information to the UE comprises the base station including the Doppler shift information in a System Information Block, SIB, transmission.
In an embodiment, the step of the base station transmitting the Doppler shift information to the UE comprises the base station including the Doppler shift information in a random access response message, Msg2, in response to the base station receiving a Random Access message, Msg1, from the UE.
In an embodiment, the UE, in response to receiving the Doppler shift information in the random access response message, Msg2, transmits a message, Msg3, on the adjusted transmission frequency.
In an embodiment, the step of the base station transmitting the Doppler shift information to the UE comprises use of one or more of RRC signalling, MAC CE signalling and DCI signalling.
In an embodiment, the step of the base station estimating Doppler shift information comprises receiving input information related to one or more of: gNB position, gNB spot beam coverage, gNB spot beam pattern, gNB velocity and UE signal.
In an embodiment, the estimated Doppler shift information, is represented by an average Doppler shift or by a Doppler spread.
In an embodiment, the average Doppler shift is represented by: 7.7; = -rs(t)dt f swdr * In an embodiment, the Doppler spread is given by: if&-MYSCOar f S(ndf According to a second aspect of the present invention, there is provided a Doppler shift estimator, for use in a satellite-based base station, gNB, operable to estimate Doppler shift on the basis of one or more inputs including: gNB position, gNB spot beam coverage, gNB spot beam pattern, gNB velocity and UE signal.
In an embodiment, the Doppler shift estimator of claim 10 operable to calculate estimated Doppler shift information, fb, represented by an average Doppler shift or by a Doppler spread.
According to a third aspect of the present invention, there is provided a base station comprising the Doppler Shift estimator of the second aspect.
According to a fourth aspect of the present invention, there is provided satellite comprising the base station of the third aspect.
According to a fifth aspect of the present invention, there is provided a User Equipment, UE, operable to adjust a transmission frequency on the basis of received Doppler shift information.
According to the present invention there is provided an apparatus and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.
Although a few preferred embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.
For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example only, to the accompanying diagrammatic drawings in which: Figure 1 shows a representation of a base station at a satellite side, in communication with a terrestrial UE, Figure 2 shows a message exchange according to a first embodiment of the invention; Figure 3 shows a message exchange according to a second embodiment of the invention; Figure 4 shows a message exchange according to a third embodiment of the invention; Figure 5 shows a Doppler shift estimator according to an embodiment of the present invention; and Figure 6 illustrates a method adopted by the estimator of Figure 5.
Figure 1 illustrates the basic scenario of embodiments of the present invention. UE 10 is located on the ground and is in communication with a Base Station (gNB) 20 on a satellite. The satellite 20 transmits and its spot beam 30 represents a concentration of power directed towards the UE 10. This helps minimise interference to other UEs. The general coverage area represents the area on the ground where the satellite's signal can be effectively received and/or decoded.
In the following, reference to gNB refers to the gNB aboard the satellite 20. As such, reference to gNB should be taken to refer to an NTN gNB.
In a first embodiment, the gNB 20 estimates the Doppler shift information and sends this information to UEs via a message. As shown in Figure 2, the gNB first estimates the Doppler shift (S100). Then, this Doppler shift information is sent to a UE via a message (S110). After a UE receives this information, it adjusts its transmission carrier frequency considering the Doppler shift (S120), e.g., correcting the Doppler shift.
Depending on when and where the Doppler shift information is sent, and what the conveyer is for this Doppler shift, a number of embodiments can be derived from the abovementioned general procedure, which will be described below. As such, the embodiment set out above and illustrated in Figure 2 may be considered to be a generic embodiment and the following embodiments set out more specific implementation details.
In a second embodiment, shown in Figure 3, the gNB estimates Doppler shift information (S200) and includes this information in a system information block (SIB) (S210).
The UE performs a cell search and decodes the SIB to acquire the Doppler shift information (S220) and then adjusts its transmission carrier frequency after decoding the SIB (S230). This can be implemented as multiples of parts per million (ppm). Other means of defining the Doppler shift may be employed as required.
When a UE acquires the Doppler shift information, as depicted in Figure 3, it adjusts its transmission (random access) carrier frequency accordingly to cancel, or compensate for, the Doppler shift. As this Doppler shift information is carried by SIB, all UEs in the cell share the same value.
An example of the format of an information element in SIB is: ASNiSTART SystemInformationBlockType::= SEQUENCE est-Doppler INTEGER (1,2,3,...), ASN1STOP The SystemInformationBlockType field descriptions include response-delay which is response delay as multiples of parts per million (ppm).
In a third embodiment, shown in Figure 4, a modified Random Access procedure is illustrated.
Here, the Doppler shift information is conveyed by the Random Access Response (RAR) in Msg2 in the random access procedure, the UE transmits Msg3 on the adjusted carrier frequency.
In more detail, UE 10 initiates the random access procedure by sending Msg1 to the gNB (S300). The gNB 20 then estimates the Doppler shift (with or without Msg1 taken into account) (S310). Next, the gNB embeds the Doppler shift information into RAR (Msg2) (S320). After decoding Msg2, the UE transmits scheduling request (Msg3) on the adjusted carrier frequency (S330). The gNB 20 replies with Msg4 (S340).
As this Doppler shift information is carried by RAR, each UE can have an individual value.
In a fourth embodiment of the invention, Doppler shift information is conveyed by RRC signalling/MAC CE/DCI. The Doppler shift information can be sent via one or more of RRC signalling and/or MAC CE and/or DCI, depending on overhead and practical considerations. In this case, the Doppler shift value is UE-specific, since it is communicated to a specific UE only.
All of the embodiments descried here rely on an estimation being made of Doppler shift. In order to estimate Doppler shift, a Doppler shift estimator is required. This is illustrated in Figure 5.
Doppler shift estimator 100 uses a plurality of inputs, as shown, and then estimates the Doppler shift on the basis of one or more of them. The inputs which it may use in its estimation include: gNB position, gNB spot beam coverage, gNB spot beam pattern, gNB velocity, UE signal. Other parameters may be defined and/or used as required.
Figure 6 illustrates one way in which the estimator 100 operates on UE 10 and gNB 20. The skilled person will appreciate that other techniques are available.
In order to understand the operation of the estimator 100, consider a one dimensional case with carrier frequency fc and speed of light c, the Doppler frequency ID of a wave impinged by the NTN gNB 20 with angle of departure (AoD) 0 can be expressed as: ID =1:fccose.
The auto-correlation function r(r) can be computed as: r(r) = f 6.-JeffficT"su dc (9) where G(0) is the angular spectrum (spot beam pattern).
Then, the Doppler spectrum 5(f) can be calculated as the Fourier transform of r(r), i.e., 5(f) =1-Hxr(t)e-2ffird-r.
If the estimated Doppler shift k is represented by the average Doppler shift, then: fiswar
-
f S(()dj.
If the estimated Doppler shift 7--f," is represented by the Doppler spread, then = \If 0,--ifOzs(r)dt fD f S(f)df This is the estimate Doppler shift, which may be incorporated into the message which is sent to the UE either via a UE-specific message or SIB message, as described before.
Embodiments of the invention provide an advantage in that Doppler shift estimation can be performed aboard the gNB and communicated to the UE which is then able to compensate for the Doppler effects and thereby increase the link reliability since signals are more likely to be properly decoded.
At least some of the example embodiments described herein may be constructed, partially or wholly, using dedicated special-purpose hardware. Terms such as 'component', 'module' or 'unit' used herein may include, but are not limited to, a hardware device, such as circuitry in the form of discrete or integrated components, a Field Programmable Gate Array (FPGA) or Application Specific Integrated Circuit (ASIC), which performs certain tasks or provides the associated functionality. In some embodiments, the described elements may be configured to reside on a tangible, persistent, addressable storage medium and may be configured to execute on one or more processors. These functional elements may in some embodiments include, by way of example, components, such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. Although the example embodiments have been described with reference to the components, modules and units discussed herein, such functional elements may be combined into fewer elements or separated into additional elements. Various combinations of optional features have been described herein, and it will be appreciated that described features may be combined in any suitable combination. In particular, the features of any one example embodiment may be combined with features of any other embodiment, as appropriate, except where such combinations are mutually exclusive. Throughout this specification, the term "comprising" or "comprises" means including the component(s) specified but not to the exclusion of the presence of others.
Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.
All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
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Claims (14)
- CLAIMS1. A method of compensating for Doppler shift in a telecommunication network comprising a terrestrial User Equipment, UE, and a base station, gNB, at a satellite, comprising the steps of: the base station estimating Doppler shift information; the base station transmitting the Doppler shift information to the UE; the UE adjusting a transmission frequency to transmit to the base station.
- 2. The method of claim 1 wherein the step of the base station transmitting the Doppler shift information to the UE comprises the base station including the Doppler shift information in a System Information Block, SIB, transmission.
- 3. The method of claim 1 wherein the step of the base station transmitting the Doppler shift information to the UE comprises the base station including the Doppler shift information in a random access response message, Msg2, in response to the base station receiving a Random Access message, Msg1, from the UE.
- 4. The method of claim 3 wherein the UE, in response to receiving the Doppler shift information in the random access response message, Msg2, transmits a message, Msg3, on the adjusted transmission frequency.
- 5. The method of claim 1 wherein the step of the base station transmitting the Doppler shift information to the UE comprises use of one or more of RRC signalling, MAC CE signalling and DCI signalling.
- 6. The method of any preceding claim wherein the step of the base station estimating Doppler shift information comprises receiving input information related to one or more of: gNB position, gNB spot beam coverage, gNB spot beam pattern, gNB velocity and UE signal.
- 7. The method of claim 6 wherein the estimated Doppler shift information, fp, is represented by an average Doppler shift or by a Doppler spread.
- 8. The method of claim 7 wherein the average Doppler shift is represented by: ffS(ncif fD= f S(ndf
- 9. The method of claim 7 wherein the Doppler spread is given by: _ 1fl1-1o)75(1)cit s(nrir
- 10. A Doppler shift estimator, for use in a satellite-based base station, gNB, operable to estimate Doppler shift on the basis of one or more inputs including: gNB position, gNB spot beam coverage, gNB spot beam pattern, gNB velocity and UE signal.
- 11. The Doppler shift estimator of claim 10 operable to calculate estimated Doppler shift information, fp, represented by an average Doppler shift or by a Doppler spread. 10
- 12. A base station comprising the Doppler Shift estimator of claim 10 or 11.
- 13. A satellite comprising the base station of claim 12.
- 14. A User Equipment, UE, operable to adjust a transmission frequency on the basis of received Doppler shift information.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1906237.1A GB2583524A (en) | 2019-05-03 | 2019-05-03 | Improvements in and relating to Doppler compensation in a non-terrestrial telecommunication network |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1906237.1A GB2583524A (en) | 2019-05-03 | 2019-05-03 | Improvements in and relating to Doppler compensation in a non-terrestrial telecommunication network |
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| Publication Number | Publication Date |
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| GB201906237D0 GB201906237D0 (en) | 2019-06-19 |
| GB2583524A true GB2583524A (en) | 2020-11-04 |
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| Application Number | Title | Priority Date | Filing Date |
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| GB1906237.1A Withdrawn GB2583524A (en) | 2019-05-03 | 2019-05-03 | Improvements in and relating to Doppler compensation in a non-terrestrial telecommunication network |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN112312382A (en) * | 2019-07-31 | 2021-02-02 | 索尼公司 | Electronic device, wireless communication method, and computer-readable storage medium |
| CN112583463B (en) * | 2019-09-30 | 2023-02-14 | 华为技术有限公司 | Beam indication method and device |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996008882A1 (en) * | 1994-09-14 | 1996-03-21 | Ericsson Inc. | Frequency error correction in a satellite-mobile communications system |
| WO1998015070A1 (en) * | 1996-09-30 | 1998-04-09 | Qualcomm Incorporated | Determination of frequency offsets in communication systems |
| WO2007013938A2 (en) * | 2005-07-20 | 2007-02-01 | Qualcomm Flarion Technologies, Inc. | Methods and apparatus for supporting timing and/or frequency corrections in a wireless communications system |
| WO2007015828A2 (en) * | 2005-07-20 | 2007-02-08 | Qualcomm Flarion Technologies, Inc. | Methods and apparatus for providing base station position information and using position information to support timing and/or frequency corrections |
| WO2008099410A2 (en) * | 2007-02-18 | 2008-08-21 | Runcom Technologies Ltd. | Wimax communication system and method |
| WO2019195410A1 (en) * | 2018-04-05 | 2019-10-10 | Qualcomm Incorporated | Techniques for initial access in wireless systems |
-
2019
- 2019-05-03 GB GB1906237.1A patent/GB2583524A/en not_active Withdrawn
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996008882A1 (en) * | 1994-09-14 | 1996-03-21 | Ericsson Inc. | Frequency error correction in a satellite-mobile communications system |
| WO1998015070A1 (en) * | 1996-09-30 | 1998-04-09 | Qualcomm Incorporated | Determination of frequency offsets in communication systems |
| WO2007013938A2 (en) * | 2005-07-20 | 2007-02-01 | Qualcomm Flarion Technologies, Inc. | Methods and apparatus for supporting timing and/or frequency corrections in a wireless communications system |
| WO2007015828A2 (en) * | 2005-07-20 | 2007-02-08 | Qualcomm Flarion Technologies, Inc. | Methods and apparatus for providing base station position information and using position information to support timing and/or frequency corrections |
| WO2008099410A2 (en) * | 2007-02-18 | 2008-08-21 | Runcom Technologies Ltd. | Wimax communication system and method |
| WO2019195410A1 (en) * | 2018-04-05 | 2019-10-10 | Qualcomm Incorporated | Techniques for initial access in wireless systems |
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| GB201906237D0 (en) | 2019-06-19 |
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