WO2011032413A1

WO2011032413A1 - Method and device for resource element mapping

Info

Publication number: WO2011032413A1
Application number: PCT/CN2010/074606
Authority: WO
Inventors: 闫鹏周; 刘磊; 李虎虎; 贾昊男
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-09-21
Filing date: 2010-06-28
Publication date: 2011-03-24
Also published as: CN102026337B; CN102026337A

Abstract

The present invention discloses a device for resource element mapping. The device includes: a mapping computing module, used for computing the signal type which should be placed in each resource element (RE) of the symbol according to the frame-number, the subframe-number and the symbol-number which are ahead of the system time by two symbols when the pulse of every symbol comes, and constituting the RE mapping-pattern; a mapping-pattern storing module, used for storing the RE mapping-pattern computed by the mapping computing module; and a mapping placing module, used for reading the signal type of RE from the RE mapping-pattern stored in the mapping-pattern storing module, and obtaining the modulated and scrambled data from the channel corresponding to the signal type according to the read signal type, when the pulse of every symbol comes. The present invention also discloses a method for resource element mapping. Through the method and device, the requirement of high processing capability of the Long Term Evolution (LTE) system can be satisfied.

Description

Method and device for mapping resource elements

The present invention relates to a resource mapping technology in a Long Term Evolution (LTE) system, and in particular, to a resource element (RE) mapping method and apparatus. Background technique

The resource element (RE, Resource Element) mapping refers to a Physical Downlink Shared Channel (PDSCH) and a Physical Downlink Shared Channel (PDCCH) when processing in the downlink physical layer in a Long Term Evolution (LTE) system. Physical Downlink Control Channel), Physical Broadcast Channel (PBCH, Physical Broadcast Channel), Primary Synchronization Channel (PSCH), SSCH (Secondary Synchronization Channel), Reference Signal (RS, Reference Signal), etc. The modulated scrambled data is placed in the frequency and timing locations specified by the 3GPP, 3 Generation Partnership Project (3GPP).

The flow of the LTE downlink physical layer processing, as shown in Figure 1, after the RE mapping, the PDSCH, PDCCH, PBCH, PSCH, SSCH, RS signals are strictly distributed in the symbols and subcarrier positions required by the 3GPP protocol; Fast Fourier Inverse The transform (IFFT, Inverse Fast Fourier Transform) module performs IFFT processing on the RE-mapped data per symbol, and the IFFT-processed time domain signal is processed into a radio frequency module by inserting a cyclic prefix (CP, Cyclic Prefix).

The format of the RE mapping is determined by various factors such as the LTE system, the number of antennas, the cell identifier (ID, Identity), the frame number, and the symbol number. The judgment conditions are cumbersome and complicated to implement. The LTE system is mainly divided into Frequency Division Duplex (FDD) and Time Division Duplex (TDD) modes. The FDD frame structure is relatively simple, and each radio frame consists of 10 none. Each of the wireless sub-frames is composed of 14 or 12 symbols. It should be noted that, for a long cyclic prefix (CP, Cyclic Prefix), each sub-frame consists of 12 symbols, and a short cyclic prefix (CP, Cyclic Prefix), each sub-frame is composed of 14 symbols; the TDD frame structure is relatively complicated, as shown in FIG. 2, each radio frame is composed of 10 radio subframes, according to the upper layer configuration, as shown in Table 1,

Table 1

The 10 radio subframes of each radio frame may be configured as a downlink subframe (D, Downlink subframe), an uplink sub-frame (U, Uplink subframe), a special sub-frame (S, Special subframe), and a special subframe. The downlink pilot time slot (DwPTS, Downlink Pilot Time Slot), the guard time slot (GP, Guard Period), and the Uplink Pilot Time Slot (UpP Pilot Time Slot), where the downlink subframe and the special subframe downlink The pilot time slot, the system downlink normal transmission data, the uplink subframe and the special subframe protection time slot, the uplink pilot time slot, and the system downlink sends 0.

The microprocessor currently used implements the RE mapping function. Although it is easy to implement, the microprocessor basically uses serial operations (even if the multi-core processor is present, the parallelism is realized to some extent, and the essence is serial operation). Can not meet the high processing power requirements of the LTE system. Summary of the invention

In view of this, the main object of the present invention is to provide a method and apparatus for mapping resource elements. To solve the problem that the existing resource element mapping cannot meet the high processing capability requirements of the LTE system.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

The present invention provides a resource element mapping apparatus, the apparatus comprising:

a mapping calculation module, configured to calculate, when the pulse of each symbol arrives, each resource element (RE) of the symbol is calculated based on a frame number, a subframe number, and a symbol number that are two symbols ahead of the system time. The type of signal that is placed to form a RE mapping pattern;

a mapping pattern storage module, configured to store the RE mapping pattern calculated by the mapping calculation module;

a mapping placement module, configured to read a signal type of the RE from the RE mapping pattern stored by the mapping pattern storage module when each pulse arrives, and from the channel corresponding to the signal type according to the read signal type Obtain the data after modulation scrambling.

The apparatus further includes: a mapping spectrum shifting module, configured to receive data provided by the mapping placement module, and perform spectrum shifting on the data.

The signal types include: a reference signal (RS), a primary synchronization channel (PSCH) signal, a secondary synchronization channel (SSCH) signal, a physical broadcast channel (PBCH) signal, a physical downlink control channel (PDCCH) signal, and a physical downlink shared channel ( PDSCH) signal.

The mapping calculation module is further configured to: determine, according to the current system, the frame number, the subframe number, and the symbol number, whether the currently calculated symbol is a special symbol of time division duplex (TDD), and when determining that it is a special symbol of the TDD, A zero-filling process is performed on all REs of the symbol.

The mapping calculation module is further configured to identify, by using a specific identifier, a signal type that each RE should be placed.

The invention also provides a mapping method of resource elements, the method comprising:

When the pulse of each symbol arrives, the signal type of each RE of the symbol is calculated based on the frame number, the subframe number, and the symbol number of two symbols ahead of the system time, and the RE mapping pattern is formed. storage; Reading a signal type of the RE from the RE mapping pattern, and acquiring modulated scrambled data from a channel corresponding to the signal type according to the read signal type.

The method further includes: performing spectral shifting on the acquired modulated scrambled data.

The signal types include: an RS signal, a PSCH signal, an SSCH signal, a PBCH signal, a PDCCH signal, and a PDSCH signal.

The method further includes: determining, according to the current system, the frame number, the subframe number, and the symbol number, whether the currently calculated symbol is a special symbol of the TDD, and determining that it is a special symbol of the TDD, when the pulse of each symbol arrives A zero-filling process is performed on all REs of the symbol.

The method further includes identifying the type of signal that each RE should be placed with a particular identification.

The invention provides a method and a device for realizing mapping of LTE downlink physical layer resource elements by using hardware description language (HDL), which is n ( n > 0 ) symbols ahead of system time when a pulse of each symbol arrives. Based on the frame number, sub-frame number, and symbol number, calculate the signal type that each RE of the symbol should be placed to form the RE mapping pattern and store it; read the signal type of the RE from the RE mapping pattern, and according to the read signal The type obtains the modulated scrambled data from the channel corresponding to the signal type. Since HDL can perform parallel pipeline operations, the DHL is used to implement the RE mapping function, which can meet the requirements of high processing capability of the LTE system and simplify the logic complexity, laying a foundation for the full implementation of LTE baseband integrated circuit (IC) in the future. DRAWINGS

1 is a flowchart of processing of an LTE downlink physical layer in the prior art;

2 is a schematic diagram of a TDD frame structure in the prior art;

3 is a schematic structural diagram of a resource element mapping apparatus according to the present invention;

4 is a flowchart of a method for mapping resource elements according to the present invention;

FIG. 5 is a flowchart of an implementation of the mapping calculation module 10. detailed description

The technical solutions of the present invention are further elaborated below in conjunction with the accompanying drawings and specific embodiments. The resource element mapping device provided by the present invention, as shown in FIG. 3, uses a hardware description language (HDL) to split the RE mapping into N (N > 2) modules, and each module is processed. Pipeline operations (that is, each module is working at every moment) to improve system processing power and simplify logic complexity.

The apparatus shown in FIG. 3 mainly includes: a mapping calculation module 10, a mapping pattern storage module 20, and a mapping placement module 30. The mapping calculation module 10 is configured to calculate, according to the frame number, the subframe number, and the symbol number of the two symbols earlier than the system time, the signal type of each RE of the symbol should be placed when the pulse of each symbol arrives , constitutes the RE mapping pattern. It should be noted that, according to the design mapping calculation module 10 and the mapping pattern storage module 20, in one symbol completion, the mapping placement module 30 is completed in one symbol, the IFFT and the interpolating CP are completed in one symbol, and the IFFT and CP represent the current system time. Therefore, the mapping calculation module 10 advances two symbols ahead of the system time. According to different design conditions, the value of the advance amount here may also be different, that is, based on the frame number, subframe number, and symbol number of n ( n > 0 ) symbols earlier than the system time, each RE of the calculated symbol should be The type of signal placed.

The mapping pattern storage module 20 is configured to store the RE mapping pattern calculated by the mapping calculation module 10. The mapping module 30 is configured to read the signal type of the RE from the RE mapping pattern stored in the mapping pattern storage module 20 when each pulse arrives, and obtain the signal type corresponding to the signal type according to the read signal type. Modulate the scrambled data.

The signal types referred to in the present invention include: an RS signal, a PSCH signal, an SSCH signal, a PBCH signal, a PDCCH signal, a PDSCH signal, and the like. The mapping calculation module 10 identifies the type of signal that each RE should be placed by using a specific identification. The specific identification process will be explained in detail later.

Preferably, the mapping calculation module 10 is further configured to determine, according to the current system, the frame number, the subframe number, and the symbol number, whether the currently calculated symbol is time division duplex (TDD, Time Division). Duplexing) special symbol, and is judged to be a special symbol of TDD (the special symbol here refers to the uplink subframe in FIG. 2, and the guard slot and the uplink pilot slot of the special subframe), the symbol All REs perform zero-fill processing.

Preferably, the apparatus may further include: a mapping spectrum shifting module 40, and a connection mapping placement module 30, configured to receive data provided by the mapping placement module 30, and perform spectrum shifting on the data. The specific frequency offset operation will be described in detail later.

It should be noted that, according to the difference in the number of antennas, the number of embedded sub-modules is different, and each sub-module corresponds to one antenna. Similarly, the mapped spectrum shifting module 40 is based on the number of antennas. The difference is that the number of embedded sub-modules is different, and each sub-module corresponds to one antenna. The mapping calculation module 10 and the mapping pattern storage module 20 do not need to provide a plurality of sub-modules, and may correspond to a plurality of antennas.

The RE mapping method implemented by the above mapping apparatus will be further elaborated below in conjunction with specific embodiments. This embodiment only uses a single 20M cell as an example to describe the flow of RE mapping. However, if multiple cells are supported, the mapping calculation module 10, the mapping pattern storage module 20, the mapping placement module 30, and the mapping spectrum shifting module 40 need to be copied in multiple copies. For example, if three cells are supported, the above needs to be performed. The mapping calculation module 10, the mapping pattern storage module 20, the mapping placement module 30, and the mapping spectrum shifting module 40 each replicate 3 copies to correspond to each cell. As shown in FIG. 4, the RE mapping process corresponding to a single 20M cell mainly includes the following steps: Step 401: When the pulse of each symbol arrives, the mapping calculation module 10 advances the frame number and sub-number of the two symbol numbers by the system time. Based on the frame number and symbol number, calculate the signal type that should be placed for each RE (1200 total) of the symbol.

The implementation flow of the mapping calculation module 10 is implemented by a state machine. As shown in FIG. 5, the pulse signal of the symbol is continuously detected in the 501 state, and if the pulse signal is detected, the state is shifted to the state 502. In the 502 state, according to the current system, frame number, subframe number, symbol number and the like, it is judged whether the currently calculated symbol is a special symbol of TDD, and if so, it goes to state 503; otherwise, it goes to state 504. The special symbol of TDD refers to the symbol corresponding to the uplink (Uplink) subframe, and the guard interval (GP, Guard Period) symbol and the Uplink symbol of the special subframe. In the 503 state, all the REs of the cell are subjected to zero-filling processing, and after execution, the state 501 is returned, waiting for a pulse of a new symbol. In the state 504, the RE mapping sub-state machine is started to perform the calculation of the RS mapping position, and 000 (signal type identification) is written at the corresponding position of the mapping pattern storage module 20, and the processing proceeds to the state 505. The calculation of the PSCH mapping position of the currently calculated symbol is performed at state 505, and 001 is written at the corresponding location of the mapping pattern storage module 20, and the processing proceeds to state 506. The calculation of the SSCH mapping position of the currently calculated symbol is performed at state 506, and 010 is written at the corresponding location of the mapping pattern storage module 20, and the processing proceeds to state 507. The calculation of the PBCH mapping position of the currently calculated symbol is performed at state 507, and 011 is written at the corresponding location of the mapping pattern storage module 20, and is processed to state 508. The calculation of the PDCCH mapping position of the currently calculated symbol is performed at state 508, and 101 is written at the corresponding location of the mapping pattern storage module 20, and the processing proceeds to state 509. The calculation of the PDSCH mapping position of the currently calculated symbol is performed in state 509, and is written 110 at the corresponding location of the mapping pattern storage module 20. After processing, the state machine transitions to the 501 state, waiting for the next trigger.

It should be noted that the calculation of the RS mapping position, the calculation of the PSCH mapping position, the calculation of the SSCH mapping position, the calculation of the PBCH mapping position, the calculation of the PDCCH mapping position, and the calculation of the PDSCH mapping position are sequentially performed according to the order of priority. of.

Step 402: The mapping pattern storage module 20 stores the RE mapping pattern calculated by the mapping calculation module 10.

In this embodiment, the mapping pattern storage module 20 is a two-port random access memory (RAM) having a depth of 1200 and a width of 3 bits. Each address represents an RE, and the 3 bits of each address store the signal type identifier that the RE needs to store. For example, when an address stores data of 000, it indicates that the location stores the RS signal; when the address is 001, it indicates the location. Store the PSCH signal; when the address is 010, it means that the location stores the SSCH letter. When the location stores Oil, it indicates that the location stores the PBCH signal; when the location stores 101, it indicates that the location stores the PDCCH signal; when the location stores 110, it indicates that the location stores the PDSCH signal.

Step 403: The mapping placement module 30 reads the signal type of the RE from the RE mapping pattern stored in the mapping pattern storage module 20 when each pulse arrives, and obtains the signal type corresponding to the signal type according to the read signal type. Modulate the scrambled data.

The mapping placement module 30 sequentially reads the signal types of the REs in the mapping pattern from the address 0 of the mapping pattern storage module 20 when each pulse arrives, and according to the read information, respectively, from the RS channel, the PSCH channel, the SSCH channel, and the PBCH. The modulated scrambled data is acquired in the channel, the PDCCH channel, and the PDSCH channel, and the data is sent to the mapped spectrum shifting module 40 together with the address of the mapping placement module 30.

Step 404, the mapping spectrum shifting module 40 receives the data provided by the mapping placement module 30, and performs spectrum shifting on the data.

The processed by the mapping placement module 30 is a frequency domain signal of Orthogonal Frequency Division Multiplexing (OFDM), which is symmetrically distributed about the frequency axis, and represents an angular frequency range of -~ and is subsequently executed. The angular frequency range of the IFFT processing is 0~; The mapped spectrum shifting module 40 is to perform spectrum shifting of the data transmitted by the mapping placement module 30. For example, if the current cell is a 20-cell, the RE with the subcarrier number less than 600 is added to the address in sequence, and the RE with the subcarrier number greater than 600 is successively reduced by 600.

The data after the spectrum shift processing is sent to the IFFT module for IFFT processing for each symbol. The time domain signal after the IFFT processing is processed by the CP and then sent to the RF module for external transmission.

In summary, since HDL can perform parallel pipeline operations, the present invention adopts DHL to implement RE mapping function, can meet the requirements of high processing capability of LTE system, and simplifies logic complexity, and fully realizes LTE baseband integrated circuit in the future ( IC, Integrated Circuit) laid the foundation. The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

A mapping device for a resource element, the device comprising:

The apparatus for mapping resource elements according to claim 1, wherein the apparatus further comprises: a mapping spectrum shifting module, configured to receive data provided by the mapping placement module, and perform spectrum shifting on the data.

The apparatus for mapping resource elements according to claim 1 or 2, wherein the signal type comprises: a reference signal (RS), a primary synchronization channel (PSCH) signal, a secondary synchronization channel (SSCH) signal, and a physical broadcast. Channel (PBCH) signal, Physical Downlink Control Channel (PDCCH) signal, and Physical Downlink Shared Channel (PDSCH) signal.

The mapping device of the resource element according to claim 1 or 2, wherein the mapping calculation module is further configured to: determine, according to the current system, the frame number, the subframe number, and the symbol number, whether the currently calculated symbol is A special symbol of time division duplex (TDD), and when it is judged to be a special symbol of TDD, a zero-filling process is performed on all REs of the symbol.

The apparatus for mapping resource elements according to claim 1 or 2, wherein the mapping calculation module is further configured to identify, by using a specific identifier, a signal type that each RE should be placed.

6. A method for mapping resource elements, the method comprising: When the pulse of each symbol arrives, the signal type of each RE of the symbol is calculated based on the frame number, the subframe number, and the symbol number of two symbols ahead of the system time, and the RE mapping pattern is formed. storage;

The signal type of the RE is read from the RE mapping pattern, and the modulated scrambled data is obtained from the channel corresponding to the signal type according to the read signal type.

The method for mapping resource elements according to claim 6, wherein the method further comprises: performing spectrum shifting on the acquired modulated scrambled data.

The method for mapping resource elements according to claim 6 or 7, wherein the signal type comprises: an RS signal, a PSCH signal, an SSCH signal, a PBCH signal, a PDCCH signal, and a PDSCH signal.

The method for mapping resource elements according to claim 6 or 7, wherein the method further comprises: determining, according to the current system, the frame number, the subframe number, and the symbol number, when the pulse of each symbol arrives Whether the calculated symbol is a special symbol of TDD, and when it is judged to be a special symbol of TDD, zero-filling processing is performed on all REs of the symbol.

The method for mapping resource elements according to claim 6 or 7, wherein the method further comprises: identifying, by using a specific identifier, a signal type that each RE should be placed.