Narrowband multi-subband time division radio remote unit and sub-band separation and combination method

Abstract

The present invention discloses a narrowband multi-subband time division radio frequency remote unit and a sub-band separation and combination method, wherein the narrowband multi-subband time division radio frequency remote unit comprises a multi-channel direct digital frequency synthesizer group, a downlink digital up-converter unit, an uplink digital down-converter unit, a multiplier group for downlink sub-band combination, a multiplier group and an accumulator for uplink sub-band separation. The present invention can save a lot of hardware resources and logic resources in the application scenario of ultra-multi-carrier by multiplexing the direct digital frequency synthesizer group.

Description

Technical Field

[0001] The present invention relates to a sub-band (carrier) separation and combining scheme, in particular to a sub-band (carrier) separation and combining scheme of a narrowband multi-sub-band time-division radio frequency remote unit. Background Art

[0002] The RF remote unit occupies an important position in the field of wireless communications. The main functions of the RF remote unit are: the downlink part performs digital up-conversion on the serial baseband data transmitted from the baseband unit through the optical fiber, and finally converts it into an intermediate frequency digital signal, and then converts it into an analog signal through the DAC, and finally transmits it through the antenna after up-conversion and amplification through the RF part; on the contrary, the uplink part receives the user signal, amplifies and down-converts it into an intermediate frequency analog signal through the RF part, and then converts it into a digital intermediate frequency signal through the ADC. The digital intermediate frequency signal is finally converted into a serial baseband signal through digital down-conversion and transmitted to the baseband unit through the optical fiber.

[0003] Digital up-conversion and digital down-conversion are the most basic functions of the radio remote unit. Digital up-conversion mainly completes the data rate increase of the baseband zero-frequency signal and the shift and separation of the sub-band (carrier) frequency to achieve the sub-band combination. Digital down-conversion mainly completes the data rate reduction of the intermediate frequency digital signal and the return of the sub-band frequency to zero to achieve the sub-band separation. The separation and combination of sub-bands is an important part of the digital intermediate frequency. For the application of many sub-bands, a large number of direct digital frequency synthesizers are required, which consumes a lot of hardware resources and logic resources. Therefore, in the application of many sub-bands, how to save hardware resources and logic processing resources through reasonable design while meeting the performance requirements is a topic worthy of in-depth research. Summary of the invention

[0004] The object of the present invention is to provide a sub-band separation and combining method for a narrowband multi-sub-band time-division radio remote unit, which saves a large amount of hardware resources and logic resources by sharing a multi-channel direct digital frequency synthesizer group for uplink and downlink and balancing the rate and area.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] Provided is a narrowband multi-subband time division radio remote unit for realizing sub-band separation and combining, comprising:

[0007] A multi-channel direct digital frequency synthesizer group, including a plurality of multi-channel direct digital frequency synthesizers, for providing a single tone signal required for sub-band frequency shifting, and synchronizing uplink and downlink data respectively through output flag bits;

[0008] A downlink digital up-converter unit connected to the multi-channel direct digital frequency synthesizer group through the downlink synchronization logic unit;

[0009] an uplink digital downconverter unit connected to the multi-channel direct digital frequency synthesizer group through the uplink synchronization logic unit;

[0010] A multiplier group for downlink sub-band combining, comprising a plurality of multipliers, and connected to both the downlink digital up-converter unit and the multi-channel direct digital frequency synthesizer group;

[0011] A multiplier group for uplink sub-band separation, comprising a plurality of multipliers, and connected to both the uplink digital down-converter unit and the multi-channel direct digital frequency synthesizer group;

[0012] An accumulator is connected to the multiplier group of the downlink sub-band combination.

[0013] According to the above technical solution, the multi-channel direct digital frequency synthesizer, the multiplier group for downlink sub-band combining, and the multiplier group for uplink sub-band separation all work in parallel in multiple modules, and the number of channels of the multi-channel direct digital frequency synthesizer group is the quotient of the total number of sub-bands and the number of parallel modules.

[0014] According to the above technical solution, the downlink digital up-converter unit increases the data rate of the baseband low-rate serial data by interpolation, and converts the data of all sub-bands into a data arrangement corresponding to the multi-pass direct digital frequency synthesizer group by serial-to-parallel conversion.

[0015] In accordance with the above technical solution, the narrowband multi-subband time-division radio remote unit further includes a reset module connected to the multi-pass direct digital frequency synthesizer group, and the reset module configures the frequency control word of the multi-pass direct digital frequency synthesizer group by resetting.

[0016] The present invention also provides a method for realizing sub-band separation and combining by a narrowband multi-sub-band time-division radio remote unit, comprising the following steps:

[0017] Each channel in the multi-channel direct digital frequency synthesizer group generates a single tone signal corresponding to multiple sub-bands; and outputs a corresponding flag bit to control the synchronization of the uplink digital down converter unit and the downlink digital up converter unit through the uplink synchronization logic unit and the downlink synchronization logic unit respectively;

[0018] The downlink digital up-converter unit interpolates the baseband low-rate serial data to the data rate required to meet the multiple sub-band combination, and simultaneously performs serial-to-parallel conversion on the data to make it consistent with the data arrangement of the multi-channel direct digital frequency synthesizer group;

[0019] The uplink digital down-converter unit extracts the width signals of the combined multiple sub-bands to a data rate required for separation of the multiple sub-bands;

[0020] The multiplier group for downlink sub-band combining multiplies the single tone signal of the multi-channel direct digital frequency synthesizer group with the baseband signal of the corresponding sub-band downlink, so that each sub-band is shifted to the agreed frequency point and then the sub-band is aggregated through the accumulator;

[0021] The uplink digital down-converter unit multiplies the single tone signal of the multi-channel direct digital frequency synthesizer group and the width signals of the multiple combined sub-bands, so as to move each sub-band to zero frequency to realize sub-band separation.

[0022] According to the above technical solution, when the sub-bands are separated and combined, the uplink and downlink sub-band data are input in parallel by multiple sub-bands.

[0023] Following the above technical solution, the output flag of the multi-channel direct digital frequency synthesizer group controls the input flag signal of the last stage decimation filter of the uplink digital downconverter unit through the uplink synchronization logic unit to control the sub-band of the multi-channel direct digital frequency synthesizer group and the sub-band of the uplink data to correspond one to one.

[0024] According to the above technical solution, the output flag of the multi-channel direct digital frequency synthesizer group controls the input flag signal of the last interpolation filter of the downlink digital up-converter unit through the downlink synchronization logic unit to control the sub-band of the multi-channel direct digital frequency synthesizer group and the sub-band of the downlink data to correspond one to one.

[0025] The beneficial effects of the present invention are as follows: the uplink digital down-converter unit and the downlink digital up-converter unit of the present invention convert the uplink and downlink data rates to appropriate values ​​according to the total effective bandwidth of the system and then perform carrier separation and combining, so that the logic resources can be fully utilized under the condition that the performance meets the requirements; the multi-channel direct digital frequency synthesizer group saves a large amount of hardware resources and logic resources by sharing the direct digital frequency synthesizer group for the uplink and downlink links. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0027] Figure 1 It is a structural block diagram of a narrowband multi-subband time-division radio remote unit solution for implementing sub-band separation and combining according to an embodiment of the present invention.

[0028] Figure 2 It is a timing diagram of data and output flag bits of a multi-channel direct digital frequency synthesizer according to an embodiment of the present invention.

[0029] Figure 3 It is a schematic diagram of the arrangement of 440 sub-bands after digital up / down conversion according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] like Figure 1 As shown, the multi-sub-band radio frequency remote unit for implementing sub-band separation and combination in the embodiment of the present invention includes a multi-channel direct digital frequency synthesizer group unit 1, a downlink synchronization logic unit 2, an uplink synchronization logic unit 3, a downlink digital up-converter unit 4, a multiplier group 5 for downlink sub-band combination, a multiplier group 6 for uplink sub-band separation, an uplink digital down-converter unit 7 and an accumulator 8.

[0032] A multi-channel direct digital frequency synthesizer group 1, comprising a plurality of multi-channel direct digital frequency synthesizers, for providing a single tone signal required for sub-band frequency shifting, and synchronizing uplink and downlink data respectively by outputting a flag bit;

[0033] A downlink digital up-converter unit 4 connected to the multi-channel direct digital frequency synthesizer group via the downlink synchronization logic unit;

[0034] an uplink digital downconverter unit 7, connected to the multi-channel direct digital frequency synthesizer group through the uplink synchronization logic unit;

[0035] A multiplier group 5 for downlink sub-band combining, comprising a plurality of multipliers, and connected to both the downlink digital up-converter unit 4 and the multi-channel direct digital frequency synthesizer group 1;

[0036] A multiplier group 6 for uplink sub-band separation, comprising a plurality of multipliers, and connected to both the uplink digital down-converter unit 7 and the multi-channel direct digital frequency synthesizer group 1;

[0037] The accumulator 8 is connected to the multiplier group 5 for combining the downlink sub-bands.

[0038] In the present invention, the multi-channel direct digital frequency synthesizer group 1, the multiplier group 5 for downlink sub-band combining, and the multiplier group 6 for uplink sub-band separation all work in parallel as multiple modules. The number of channels of the multi-channel direct digital frequency synthesizer group 1 is the quotient of the total number of sub-bands (the number of uplink or downlink sub-bands) and the number of parallel modules (the number of uplink or downlink parallel modules).

[0039] Furthermore, the downlink digital up-converter unit 4 increases the data rate of the baseband low-rate serial data by interpolation, and converts the data of all sub-bands into a data arrangement corresponding to the multi-pass direct digital frequency synthesizer group 1 by serial-to-parallel conversion.

[0040] The narrowband multi-subband time-division radio remote unit further comprises a reset module (not shown in the figure) connected to the multi-pass direct digital frequency synthesizer group 1, and the reset module configures the frequency control word of the multi-pass direct digital frequency synthesizer group 1 by resetting.

[0041] The method for implementing sub-band separation and combining based on the narrowband multi-sub-band time division radio remote unit specifically comprises the following steps:

[0042] Each channel in the multi-channel direct digital frequency synthesizer group 1 generates a single tone signal corresponding to each sub-band; and outputs a corresponding flag bit to control the synchronization of the uplink digital down converter unit 7 and the downlink digital up converter unit 4 through the uplink synchronization logic unit 3 and the downlink synchronization logic unit 2 respectively;

[0043] The downlink digital up-converter unit 4 interpolates the baseband low-rate serial data to the data rate required to meet the multiple sub-band combination, and simultaneously performs serial-to-parallel conversion on the data to make it consistent with the data arrangement of the multi-channel direct digital frequency synthesizer group 1;

[0044] The uplink digital down-converter unit 7 extracts the width signals of the combined multiple sub-bands to a data rate required for separation of the multiple sub-bands;

[0045] The multiplier group 5 for downlink sub-band combining performs multiplication operation on the single tone signal of the multi-channel direct digital frequency synthesizer group 1 and the baseband signal of the corresponding sub-band downlink, so that each sub-band is shifted to the agreed frequency point and then the sub-band is aggregated through the accumulator;

[0046] The uplink digital down-converter unit 7 performs multiplication operation on the single tone signal of the multi-channel direct digital frequency synthesizer group 1 and the width signals of the multiple combined sub-bands, so as to move each sub-band to zero frequency to realize sub-band separation.

[0047] When the sub-bands are separated and combined, the uplink and downlink sub-band data are input in parallel by multiple sub-bands.

[0048] The flag outputted by the multi-channel direct digital frequency synthesizer group 1 controls the input flag signal of the last stage decimation filter of the uplink digital down converter unit 7 through the uplink synchronization logic unit 3 to control the sub-band of the multi-channel direct digital frequency synthesizer group to correspond one to one with the sub-band of the uplink data.

[0049] The output flag of the multi-channel direct digital frequency synthesizer group 1 controls the input flag signal of the last interpolation filter of the downlink digital up-converter unit 4 through the downlink synchronization logic unit 2 to control the sub-band of the multi-channel direct digital frequency synthesizer group 1 and the sub-band of the downlink data to correspond one to one.

[0050] like Figure 2As shown, the multi-channel direct digital frequency synthesizer of the embodiment of the present invention takes 16 channels as an example to generate single tone signals corresponding to 16 sub-bands. In this embodiment, the total number of sub-bands is 440, so 28 parallel multi-channel direct digital frequency synthesizers are required. The frequency control word of the multi-channel direct digital frequency synthesizer group is input into the multi-channel direct digital frequency synthesizer group through the initialization file when the multi-channel direct digital frequency synthesizer group is reset.

[0051] According to the relationship between system clock and data rate, such as Figure 3 As shown, the downlink digital up-converter unit 4 or the uplink digital down-converter unit 7 converts the 440 sub-band signals into parallel data in groups of 28 sub-bands, and the data is processed in 16 clock cycles. The multi-channel direct digital frequency synthesizer group 1 is also a group of 28 direct digital frequency synthesizers, which enables each sub-band of the baseband data to correspond to the single tone signal of the corresponding sub-band of the multi-channel direct digital frequency synthesizer group 1, so as to prepare for further data processing.

[0052] The downlink digital up-converter unit 4 interpolates the low-rate serial data of the baseband to the data rate required to meet the 440 sub-band combination, and converts the data into serial-to-parallel data to make it consistent with the data arrangement of the direct digital frequency synthesizer group 1, so as to make the rate and area of ​​the logic implementation (i.e., the amount of logic resources consumed) more reasonable. The consistency of data arrangement means that the arrangement order of the sub-bands corresponds to the arrangement order of the single tones generated by the direct digital frequency synthesizer group, that is, sub-band 0 corresponds to the single tone 0 generated by the frequency synthesizer group. You can check the comparison Figure 2 and Figure 3 .

[0053] The uplink digital down-converter unit 7 extracts the combined 440 sub-band width signals to a data rate required for 440 sub-band separation, facilitating subsequent data processing;

[0054] The multiplier includes an uplink multiplier unit 6 and a downlink multiplier unit 5. Before performing multiplication, the uplink digital downconverter unit 7 and the downlink digital upconverter unit 4 convert the data rate and data arrangement of the uplink and downlink data to be consistent with the data of the direct digital frequency synthesizer group 1, thus preparing for the multiplication operation.

[0055] The downlink multiplier unit 5 performs multiplication operation on the single tone signal of the multi-channel direct digital frequency synthesizer group 1 and the baseband signal of the corresponding sub-band downlink, so that each sub-band is moved to the agreed frequency point and then the sub-band aggregation is realized through the accumulator unit 8. The uplink multiplier unit 6 performs multiplication operation on the single tone signal of the multi-channel direct digital frequency synthesizer group 1 and the width signal of the combined 440 sub-bands, so that each sub-band is moved to zero frequency to realize sub-band separation.

[0056] The uplink digital downconverter unit 7 includes several stages of data extraction filter units, and each stage of the filter starts to work and outputs the extracted and filtered data after the ready input signal is valid. The present invention uses the ready flag output by the multi-channel direct digital frequency synthesizer group 1 to control the ready input signal of the last stage of the extraction filter of the uplink digital downconverter unit 7, so that the uplink digital downconverter unit 7 and the multi-channel direct digital frequency synthesizer group unit 1 are synchronized, so that each sub-band can be correctly shifted to zero frequency after the uplink combined broadband signal is multiplied with the output signal of the direct digital frequency synthesizer group 1 to achieve sub-band separation.

[0057] In order to make the sub-bands correspond one-to-one when the downlink data and the output data of the multi-channel direct digital frequency synthesizer group 1 are multiplied, and then each sub-band can be correctly moved to the specified frequency point, the present invention needs to associate the multi-channel direct digital frequency synthesizer group 1 with the downlink digital up-converter unit 4.

[0058] In the present invention, the downlink digital up-converter unit 4 comprises several stages of data interpolation filter units, and each stage of the filter starts to work and outputs the interpolated filtered data after the ready input signal is valid. The specific method of associating the multi-channel direct digital frequency synthesizer group 1 with the downstream digital up-converter unit 4 is as follows: when the last interpolation filter of the downstream digital up-converter unit is reset, the ready input signal of the filter is made valid; after the filter has gone through two complete processing cycles, the ready input of the filter is first set to be invalid to make the filter in a waiting state; after the filter waits for a certain period of time, the last signal of the multi-channel direct digital frequency synthesizer group 1 is assigned to the ready signal of the filter and the ready of the filter is kept in this state, so that the ready of the filter of the downstream digital up-converter unit 4 and the last signal of the direct digital frequency synthesizer group are associated, because the next clock cycle of the ready of the filter of the downstream digital up-converter unit 4 outputs the first data of a data cycle, and the next clock cycle of the last signal of the direct digital frequency synthesizer group also outputs the first data of a data cycle, so that the data of the downstream digital up-converter unit 4 and the data of the multi-channel direct digital frequency synthesizer group 1 can be synchronized. After the two groups of data aligned by the above method enter the multiplier unit 5 for multiplication, each sub-band can be moved to the specified frequency point.

[0059] The present invention associates the output flag of the multi-channel direct digital frequency synthesizer group with the input flag of the uplink digital down converter 7 and the input flag of the downlink digital up converter 4, so that the uplink and downlink share the direct digital frequency synthesizer group. For applications with many sub-bands, this solution of sharing the multi-channel direct digital frequency synthesizer group can not only meet the requirements of sub-band separation but also save a lot of hardware resources and logic resources.

[0060] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A narrowband multi-subband radio remote unit for realizing sub-band separation and combining, characterized in that: include: A multi-channel direct digital frequency synthesizer group, including a plurality of multi-channel direct digital frequency synthesizers, for providing a single tone signal required for sub-band frequency shifting, and synchronizing uplink and downlink data respectively through output flag bits; A downlink digital up-converter unit connected to the multi-channel direct digital frequency synthesizer group via a downlink synchronization logic unit; an uplink digital downconverter unit connected to the multi-channel direct digital frequency synthesizer group via an uplink synchronization logic unit; A multiplier group for downlink sub-band combining, comprising a plurality of multipliers, and connected to both the downlink digital up-converter unit and the multi-channel direct digital frequency synthesizer group; A multiplier group for uplink sub-band separation, comprising a plurality of multipliers, and connected to both the uplink digital down-converter unit and the multi-channel direct digital frequency synthesizer group; An accumulator is connected to the multiplier group of the downlink sub-band combination.

2. The narrowband multi-subband radio remote unit for realizing sub-band separation and combination according to claim 1, characterized in that: The multi-channel direct digital frequency synthesizer, the multiplier group for downlink sub-band combining, and the multiplier group for uplink sub-band separation all work in parallel as multiple modules, and the number of channels of the multi-channel direct digital frequency synthesizer group is the quotient of the total number of sub-bands and the number of parallel modules.

3. The narrowband multi-subband radio remote unit for realizing sub-band separation and combination according to claim 1, characterized in that: The downlink digital up-converter unit increases the data rate of the baseband low-rate serial data by interpolation, and converts the data of all sub-bands into a data arrangement corresponding to the multi-channel direct digital frequency synthesizer group by serial-to-parallel conversion.

4. The narrowband multi-subband radio remote unit for realizing sub-band separation and combination according to claim 1, characterized in that: The narrowband multi-sub-band radio remote unit further comprises a reset module connected to the multi-channel direct digital frequency synthesizer group, and the reset module configures the frequency control word of the multi-channel direct digital frequency synthesizer group by resetting.

5. A method for implementing sub-band separation and combining based on the narrowband multi-sub-band radio remote unit of claim 1, characterized in that: The following steps are involved: Each channel in the multi-channel direct digital frequency synthesizer group generates a single tone signal corresponding to multiple sub-bands; and outputs a corresponding flag bit to control the synchronization of the uplink digital down converter unit and the downlink digital up converter unit through the uplink synchronization logic unit and the downlink synchronization logic unit respectively; The downlink digital up-converter unit interpolates the baseband low-rate serial data to the data rate required to meet the multiple sub-band combination, and simultaneously performs serial-to-parallel conversion on the data to make it consistent with the data arrangement of the multi-channel direct digital frequency synthesizer group; The uplink digital down-converter unit extracts the width signals of the combined multiple sub-bands to a data rate required for separation of the multiple sub-bands; The multiplier group for downlink sub-band combining multiplies the single tone signal of the multi-channel direct digital frequency synthesizer group with the baseband signal of the corresponding sub-band downlink, so that each sub-band is shifted to the agreed frequency point and then the sub-band is aggregated through the accumulator; The uplink digital down-converter unit multiplies the single tone signal of the multi-channel direct digital frequency synthesizer group and the width signals of the multiple combined sub-bands, so as to move each sub-band to zero frequency to realize sub-band separation.

6. The method for implementing sub-band separation and combining by a narrowband multi-sub-band radio remote unit according to claim 5, characterized in that: When the sub-bands are separated and combined, the uplink and downlink sub-band data are input in parallel by multiple sub-bands.

7. The method for implementing sub-band separation and combining by a narrowband multi-sub-band radio remote unit according to claim 5, characterized in that: The output flag of the multi-channel direct digital frequency synthesizer group controls the input flag signal of the last stage decimation filter of the uplink digital down converter unit through the uplink synchronization logic unit to control the sub-band of the multi-channel direct digital frequency synthesizer group and the sub-band of the uplink data to correspond one to one.

8. The method for implementing sub-band separation and combining by a narrowband multi-sub-band radio remote unit according to claim 5, characterized in that: The output flag of the multi-channel direct digital frequency synthesizer group controls the input flag signal of the last interpolation filter of the downstream digital up-converter unit through the downstream synchronization logic unit to control the sub-band of the multi-channel direct digital frequency synthesizer group and the sub-band of the downstream data to correspond one to one.

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