Apparatus for receiving radio frequency signals and method of operating an apparatus
11539388 · 2022-12-27
Assignee
Inventors
- Benny Vejlgaard (Gistrup, DK)
- Simon Svendsen (Aalborg, DK)
- Johannes Harrebek (Aalborg, DK)
- Christian Rom (Aalborg, DK)
- Samantha Caporal del Barrio (Aalborg, DK)
Cpc classification
International classification
H04B1/10
ELECTRICITY
Abstract
Apparatus for receiving radio frequency, RF, signals, comprising at least two antenna panels, wherein each of the at least two antenna panels is configured to provide a respective received signal with an associated frequency spectrum, wherein the apparatus is configured to apply a frequency shift to at least one of the received signals such that center frequencies of at least two adjacent frequency spectra comprise a predetermined frequency distance from each other.
Claims
1. Apparatus for receiving radio frequency (RF) signals from first and second antenna panels configured to provide respective first and second received signals with associated first and second frequency spectra, wherein the apparatus comprises: first and second RF front ends respectively associated with the first and second antenna panels and configured to respectively apply RF signal processing to the first and second received signals; one or more frequency shift units configured to apply a frequency shift to at least one of the first and second received signals or at least one signal derived from at least one of the first and second received signals to form first and second adjacent signals having adjacent frequency spectra such that center frequencies of the adjacent frequency spectra comprise a predetermined frequency distance from each other; a combiner configured to combine the first and second adjacent signals to form a single combined signal having an aggregated bandwidth; and one or more downstream processing stages configured to process the single combined signal using common signal processing to generate at least one control signal for controlling the RF signal processing of at least one of the first and second RF front ends, wherein the one or more downstream processing stages are configured to handle the aggregated bandwidth of the single combined signal.
2. The apparatus according to claim 1, wherein the one or more frequency shift units are configured to apply the frequency shift such that the adjacent frequency spectra do not overlap.
3. The apparatus according to claim 1, wherein each frequency shift unit is a coordinate rotation digital computer.
4. The apparatus according to claim 1, wherein the one or more frequency shift units are arranged in the first and second RF front ends.
5. The apparatus according to claim 1, wherein the one or more downstream processing stages comprise a transceiver stage comprising the one or more frequency shift units.
6. The apparatus according to claim 1, wherein the one or more frequency shift units are arranged between the one or more downstream processing stages and the RF front ends of the apparatus.
7. The apparatus according to claim 1, wherein the one or more downstream processing stages are configured to separate the adjacent frequency spectra by filtering.
8. The apparatus according to claim 1, wherein the apparatus is configured to perform at least one of: configuring the first and second antenna panels for simultaneous operation, configuring a transceiver stage and a baseband processing stage to operate with a bandwidth corresponding to the aggregated bandwidth of the single combined signal, configuring RF front ends associated with the first and second antenna panels to perform measurements, and separating the adjacent frequency spectra of different ones of the measurements and decoding individually each of the measurements.
9. The apparatus according to claim 1, wherein the apparatus is configured to at least temporarily perform at least one of the following elements using the first and second antenna panels in parallel: initial beam acquisition, user equipment mobility measurements, and radio link failure recovery procedures.
10. The apparatus of claim 1, further comprising the first and second antenna panels.
11. The apparatus of claim 1, wherein: the apparatus is configured to receive one or more additional RF signals from one or more additional antenna panels; the one or more frequency shift units are configured to generate three or more adjacent signals having three or more adjacent frequency spectra; the combiner is configured to combine the three or more adjacent signals into the single combined signal having the aggregated bandwidth; and the one or more downstream processing stages are configured to process the single combined signal, wherein the one or more downstream processing stages are configured to handle the aggregated bandwidth of the single combined signal.
12. The apparatus of the claim 1, wherein total bandwidth of the first and second frequency spectra of the first and second received signals is greater than the aggregated bandwidth of the single combined signal.
13. Method of operating an apparatus for receiving RF signals from first and second antenna panels configured to provide respective first and second received signals with associated first and second frequency spectra, the method comprising: applying front-end RF signal processing to the first and second received signals; applying a frequency shift to at least one of the first and second received signals or to at least one signal derived from at least one of the first and second received signals to form first and second adjacent signals having adjacent frequency spectra such that center frequencies of the adjacent frequency spectra comprise a predetermined frequency distance from each other; combining the first and second adjacent signals to form a single combined signal having an aggregated bandwidth; and processing the single combined signal at one or more downstream processing stages using common signal processing to generate at least one control signal for controlling the front-end RF signal processing, wherein the one or more downstream processing stages are configured to handle the aggregated bandwidth of the single combined signal.
14. The method according to claim 13, wherein the frequency shift is applied such that the adjacent frequency spectra do not overlap.
15. The method according to claim 13, further comprising at least temporarily performing at least one of the following elements using the first and second antenna panels in parallel: initial beam acquisition, user equipment mobility measurements, and radio link failure recovery procedures.
16. The method of claim 13, wherein the apparatus further comprises the first and second antenna panels.
17. The method of claim 13, further comprising receiving one or more additional RF signals from one or more additional antenna panels, wherein: the frequency shift is applied to generate three or more adjacent signals having three or more adjacent frequency spectra; the three or more adjacent signals are combined into the single combined signal having the aggregated bandwidth; and the single combined signal is processed at the one or more downstream processing stages, wherein the one or more downstream processing stages are configured to handle the aggregated bandwidth of the single combined signal.
18. The method of claim 13, wherein total bandwidth of the first and second frequency spectra of the first and second received signals is greater than the aggregated bandwidth of the single combined signal.
Description
BRIEF DESCRIPTION OF THE FIGURES
(1) Some exemplary embodiments will now be described with reference to the accompanying drawings in which:
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DESCRIPTION OF EXEMPLARY EMBODIMENTS
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(12) According to further exemplary embodiments, the apparatus 100 may e.g. be used for and/or within a user equipment (UE) 10 of a wireless, particularly cellular, communications systems such as e.g. of the 5G (fifth generation) type. Particularly, further exemplary embodiments may e.g. be used for enhancing existing UE and/or UE-related procedures of 5G Release 15, cf. e.g. 3GPP TR 21.915 V15.0.0 (2019 September), thus e.g. enhancing a conventional 5G/NR capable UE.
(13) According to further exemplary embodiments, the apparatus 100 may e.g. be configured to receive and/or process RF signals in at least one of the frequency ranges FR1, FR2 as e.g. defined in Table 5.5.4.1-1 of 3GPP TR 21.915 V15.0.0 (2019 September).
(14) Further, there is currently an ongoing study item titled “Study on NR beyond 52.6 GHz” (RP-182861) considering using RF signals in frequency ranges above FR2. According to further exemplary embodiments, the apparatus 100 may e.g. be configured to receive and/or process RF signals in at least one frequency range above 52.6 GHz.
(15) According to further exemplary embodiments, the antenna panels 110a, 110b, 110c may be arranged at different locations and/or with different orientations with respect to each other and/or a common reference such as a common carrier (not depicted) and/or a reference plane of the UE, e.g. a printed circuit board of the UE 10 or the like.
(16) According to further exemplary embodiments, each of the at least two antenna panels 110a, 110b, 110c is configured to provide a respective received signal RXa, RXb, RXc with an associated frequency spectrum, wherein the apparatus 100 is configured to apply a frequency shift to at least one of the received signals RXa, RXb, RXc or to at least one signal derived from at least one of the received signals RXa, RXb, RXc such that center frequencies of at least two adjacent frequency spectra comprise a predetermined frequency distance from each other. This is schematically depicted by
(17) This enables to at least temporarily separate the frequency spectra SPa, SPb related to the different antenna panels 110a, 110b (
(18) According to further exemplary embodiments, the apparatus 100 (
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(20) While the aforementioned example focuses on two adjacent frequency spectra SPa, SPb, for simplicity, according to further exemplary embodiments, and without loss of generality, the principle according to the embodiments may also be applied to more than two antenna panels 110a, 100b, 110c and their related received signals RXa, RXb, RXc and associated frequency spectra. As an example, if the apparatus 100 comprises three antenna panels 110a, 110b, 110c, as exemplarily depicted by
(21) By contrast, conventional apparatus for receiving RF signals may comprise a structure as exemplarily depicted by
(22) According to further exemplary embodiments, cf. e.g.
(23) According to further exemplary embodiments, the apparatus 100 (
(24) According to further exemplary embodiments, at least one of the antenna panels 110a, 110b may comprise a plurality (e.g., 8 or more, particularly 13 or more, more particularly 20 or more, e.g. 33) of antenna elements and/or an antenna array, e.g. of the uniform linear array, ULA, type. In this regard,
(25) According to further exemplary embodiments, at least one of the RF front ends RFa, RFb (
(26) According to further exemplary embodiments, at least one of the RF front ends RFa, RFb (
(27) According to further exemplary embodiments, the output signals of the phase shifters PS may be combined, i.e. added, by means of the combiner CMBa. According to further exemplary embodiments, an output signal of the combiner CMBa may be considered as the received signal RXa of the antenna panel 110a, to which e.g. the frequency shift may be applied, e.g. by the unit 120a, whereby the frequency shifted signal RXa1 is obtained.
(28) Similarly, the output signals of the phase shifters PS of the second RF front end RFb of
(29) According to further exemplary embodiments, the output signals RXa1, RXb1 of the frequency shift units 120a, 120b may be combined, i.e. added, by a further combiner CMB providing an aggregated RF received signal to the transceiver stage TRX for further processing, which, in turn, provides one or more signals derived from said transceiver stage processing to a baseband processing stage BB for baseband processing. As an example, the aggregated RF received signal available at the output of the further combiner CMP may comprise a spectrum comparable to the right side of
(30) According to further exemplary embodiments, processing within the transceiver stage TRX may e.g. comprise at least one of: filtering, gain control, RF control (i.e. providing one or more control signals CTRLa, CTRLb to the RF front ends RFa, RFb (e.g., for the local control logic of said RF front ends RFa, RFb), particularly based on operational parameters of the transceiver stage TRX, up-conversion, down-conversion.
(31) According to further exemplary embodiments, processing within the baseband processing stage may e.g. comprise a control of the operation of the apparatus.
(32) According to further exemplary embodiments, cf.
(33) Similar to
(34) In addition to the elements LNA, PS, CMBa of
(35) According to further exemplary embodiments, the RF front end RFa of
(36) According to further exemplary embodiments, the frequency shift unit, e.g. CORDIC unit 120a, applies the frequency shift to the digital signal s2a as obtained at the output of the ADC 132a.
(37) According to further exemplary embodiments, the RF front end RFb of
(38) According to further exemplary embodiments, processing within the transceiver stage TRX of
(39) According to further exemplary embodiments, cf.
(40) CORDIC unit, may e.g. also be provided in the transceiver stage TRX and may apply the frequency shift to the digital signal s2a, s2b as obtained at the output of the ADC 132a, 132b in the transceiver stage TRX. In these embodiments 100b, the RF front ends RFa, RFb are not required to comprise a mixer and/or ADC and/or frequency shift unit, as these components are provided in the transceiver stage TRX. In other words, according to further exemplary embodiments, the RF front ends RFa, RFb of
(41) The embodiments 100a of
(42) According to further exemplary embodiments, the at least one frequency shift unit 120a, 120b is arranged between a or the transceiver stage TRX and a or the RF front end RFa, RFB, cf. e.g.
(43) According to further exemplary embodiments, the transceiver stage TRX and, optionally, a baseband processing stage BB of the apparatus 100, 100a, 100b are configured to process signals with a bandwidth corresponding to an aggregated bandwidth of the frequency spectra SPa, SPb (
(44) According to further exemplary embodiments, the apparatus, preferably the baseband processing stage and/or the transceiver stage, is configured to separate the frequency spectra SPa, SPb (
(45) According to further exemplary embodiments, the apparatus 100, 100a, 100b is configured to at least temporarily operate the at least two antenna panels 110a, 110b simultaneously or in a temporally at least partly overlapping fashion, whereby e.g. beam measurements and/or other aspects, e.g. of Beam Management, particularly at a UE side, may be accelerated.
(46) According to further exemplary embodiments, cf.
(47) According to further exemplary embodiments, cf.
(48) As an example,
(49) According to further exemplary embodiments, cf.
(50) Further exemplary embodiments relate to a user equipment, UE, 10 comprising at least one apparatus 100, 100a, 100b according to the embodiments.
(51) Further exemplary embodiments relate to a method of operating an apparatus 100, 100a, 100b for receiving radio frequency, RF, signals, as already explained above with reference to
(52) According to further exemplary embodiments, the apparatus 100, 100a, 100b applies the frequency shift to the at least one of the received signals RXa, RXb (or to signals s2a, s2b derived therefrom) such that the at least two frequency spectra SPa, SPb of the received signals (or of the signals derived therefrom) do not overlap.
(53) According to further exemplary embodiments, the apparatus at least temporarily performs at least one of the following elements using the at least two antenna panels in parallel: initial beam acquisition, user equipment mobility measurements, radio link failure recovery procedures.
(54) Further exemplary embodiments relate to a use of the apparatus 100, 100a, 100b according to the embodiments and/or the UE 10 according to the embodiments and/or the method according to the embodiments for at least one of: a) simultaneous reception of RF signals from a plurality of antenna panels 110a, 110b, 110c, b) performing at least one of the following elements using the at least two antenna panels 110a, 110b, 110c in parallel: initial beam acquisition, user equipment mobility measurements, radio link failure recovery procedures, c) decreasing a time needed for switching to another UE antenna panel 110a, 110b, 110c and/or beam, d) enabling monitoring of alternative links without disturbing an existing primary link, e) reducing a search time for beam search, f) reducing a current and/or energy consumption, particularly for beam search, g) reducing a scanning time for initial (beam) acquisition and/or neighbor cell measurements.
(55) In the following, further aspects and exemplary embodiments are disclosed which may be—either alone or in combination with each other—combined with any of the above explained exemplary embodiments or any combination thereof.
(56) According to further exemplary embodiments, each antenna panel 110a, 110b, 110c can measure one beam (e.g., corresponding to a code book entry) at one instant of time or time step, i.e. the UE 10 can have not only one measurement from one antenna panel per time step, as with some conventional architectures (
(57) According to further exemplary embodiments, the baseband processing stage BB may be configured to calculate and/or demodulate received signals RXa, RXb associated with each antenna panel individually. Thus, e.g. individual RF power measurements based on SSB (SS/PBCH Block, Synchronization Signal (SS) and Physical Broadcast Channel (PBCH)) reference symbols or CSI (Channel State Information)-RS (Reference Signal) transmitted symbol from a gNB beam may be made.
(58) According to further exemplary embodiments, the UE 10 (
(59) According to further exemplary embodiments, the UE 10 may assume that reception occasions of a physical broadcast channel (PBCH), Primary Sync Signal (PSS), and Secondary Sync Signal (SSS) are in consecutive symbols and form a SS/PBCH block.
(60) According to further exemplary embodiments, in the context of SSB mapping in the time domain, the first symbol is the PSS, second symbol is PBCH, third symbol is SSS and fourth symbol is PBCH. According to further exemplary embodiments, a first symbol index of a candidate SSB may be determined by the UE 10 according to a subcarrier spacing of the SSB, wherein index “0” e.g. corresponds to a first symbol of a first slot in a half-frame. To enable a beam sweeping of SS and PBCH, according to further exemplary embodiments, a transmission of SS blocks may be organized in a periodical series of SS burst set such that the transmission of SS blocks within SS burst set is confined to a 5 ms window (half radio frame), regardless of the SCS (subcarrier spacing).
(61) According to further exemplary embodiments, in the context of SSB resource mapping in the frequency domain, an SS/PBCH block may consist of 240 contiguous subcarriers with the subcarriers numbered in increasing order from 0 to 239 within the SS/PBCH block. Thus, a maximum bandwidth of the SSB is 240 subcarriers*240 kHz subcarrier spacing (for FR2, numerology 4).fwdarw.57.6 MHz spacings. According to further exemplary embodiments, the SSB bandwidth of e.g. 57.6 MHz is not a problem to combine in frequency, as proposed by exemplary embodiments, because a useful signal bandwidth of the UE 10 may e.g. be 400 MHz.
(62) According to further exemplary embodiments, assuming that the UE 10 comprises six UE antenna panels 110a, 110b, . . . , it is possible to sample all associated 6 SSB blocks of these six UE antenna panels in a 345.6 MHz bandwidth BW. This may be particularly advantageous, because according to further exemplary embodiments, six UE antenna panels enable to cover 360 degree, i.e. a full spherical coverage. In other words, even with an antenna panel configuration providing six UE antenna panels, which may enable full spherical coverage, efficient, particularly simultaneous, processing of received signals RXa, RXb, . . . associated with said six UE antenna panels, e.g. for sampling said six SSB blocks, is enabled.
(63) According to further exemplary embodiments, e.g. for an exemplary beam scanning procedure, the UE 10 (
(64) According to further exemplary embodiments, e.g. for an UE connected state, a mobility scan on alternative antenna panels 110b, 110c, . . . may be performed in parallel, especially while maintaining a currently active link towards a serving gNB, e.g. on a main antenna panel 110a. This may be beneficial e.g. for a low latency critical scenario effectively removing monitoring overhead. In this case, as an example, the receiver bandwidth requirement of a receiver path of the transceiver TRX may be:
(65) #Monitor_UE_panels*SSB+active_link_BW<TRX_BW_max, wherein #Monitor_UE_panels characterizes the number of simultaneously active panels for monitoring, SSB characterizes the bandwidth associated with one SSB, active_link_BW characterizes a bandwidth required for a currently active link, and TRX_BW_max characterizes the maximum bandwidth of the receiver path of the transceiver TRX.
(66) According to further exemplary embodiments, the UE 10 may decode the MIB (Master Information Block) & SIB1 (System Information Block 1) of all potential handover gNBs and may time its own beam scan to a periodicity of the SSB burst so it may measure on the same SSB index each SSB burst. According to further exemplary embodiments, the UE 10 may only request a repetition of CSI-RS/SSB from the gNB it is connected to.
(67) According to further exemplary embodiments, the UE 10 may, preferably via its baseband processing stage BB, calculate and/or demodulate received signals from each UE antenna element 110a, 110n, . . . individually. According to further exemplary embodiments, the UE 10 may, preferably via its baseband processing stage BB, perform RF power measurements based on SSB reference symbols and/or any transmitted symbols from a beam of a gNB.
(68) According to further exemplary embodiments, the principle according to the embodiments may be used for panel switching of antenna panels and/or beam management and/or inter-cell mobility.
(69) According to further exemplary embodiments, the principle according to the embodiments may support both an idle/inactive state and a connected state of the UE 10.
(70) According to further exemplary embodiments, the SSB timing is known by the UE 10 and can be used to fine tune the timing for the search.
(71) According to further exemplary embodiments, for the UE connected state, a parallel mobility scan on alternative antenna panels may be performed while maintaining an active link towards a serving gNB on the main antenna panel.
(72) According to further exemplary embodiments, the UE may scan two antenna panels simultaneously, by using only one polarization at each panel, which may be sufficient for SSB characterization.
(73) According to further exemplary embodiments, the measurements can be used for a) Initial beam selection, b) panel switching, c) beam management, c) inter-cell mobility.
(74) According to further exemplary embodiments, a configuration of the RF front end(s) RFa, RFb may include: a) Time slot (start and stop)—e.g., characterizing a timing of general reception for BB decoding, b) Center frequency fc, c) Bandwidth BW, d) Beam codebook entry/entries.
(75) According to further exemplary embodiments, exemplary RF front end measurements may distinguish a) initial cell search (after switching on the UE 10, or after a coverage hole, or after an extreme power saving mode), idle/inactive, and connected.
(76) According to further exemplary embodiments, if an antenna panel is blocked, the measurements for that individual panel can be switched off (e.g., for further current saving), or one may keep them on as allowed to listen still.
(77) According to further exemplary embodiments, the principle according to exemplary embodiments may be combined with a combination of hybrid architecture and CORDIC unit, meaning that a hybrid beamforming architecture can still have time and current consumption savings implementing the “CORDIC architecture” according to exemplary embodiments.
(78) The principle according to exemplary embodiments enables parallel UE antenna panels operation in receive (Rx) operation. In a multi-panel UE, which comprises two or more antenna panels 110a, 110b, applying the principle according to exemplary embodiments may significantly decrease the time needed for switching to another UE antenna panel & beam since the panel measurements performed on the candidate UE antenna panels can be done in parallel, i.e. simultaneously. Moreover, the principle according to exemplary embodiments may enable monitoring of alternative links without disturbing the primary link thus enhancing throughput. Furthermore, the current consumption may be lower due to the lower search time.
(79) For higher RF frequencies (e.g. FR4, beyond 52.6 GHz), path loss will increase, and higher antenna gain may be required to maintain enough link budget. Higher antenna gain, however, may result in narrower beams. Narrower beams may require more measurement points to do a full spherical sweep. These issues may be addressed by the principle according to exemplary embodiments, because the simultaneous measurements enabled by the embodiments may accelerate the required measurements.