CN110830150B

CN110830150B - Shared data channel transmission method and equipment for wireless communication

Info

Publication number: CN110830150B
Application number: CN201810890298.6A
Authority: CN
Inventors: 黎光洁; 王明威; 李春宏; 吴冶
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-08-07
Filing date: 2018-08-07
Publication date: 2023-06-09
Anticipated expiration: 2038-08-07
Also published as: CN110830150A

Abstract

The invention discloses a shared data channel sending method for wireless communication, and relates to the field of wireless communication. And more particularly, to a method for transmitting short messages and data of a shared data channel in wide area internet of things communication. The method comprises the following steps: the data information is preprocessed based on a shared Data Channel (DCH), and is mapped and loaded into data symbols according to a predefined data symbol format, and is used for data transmission after secondary scrambling processing, wherein the shared data channel is used for carrying short message and PDU data transmission. The wireless communication channel transmission method provided by the invention introduces the predefined variable-length frequency domain equalization PCP into the shared data channel in the channel transmission, can realize more efficient modulation, and simultaneously completes channel estimation according to different types of short messages or data, thereby jointly improving the channel estimation quality. And the shared data channel can bear the sending of the short message and PDU data, can carry out correct demodulation and decoding under very low condition, has smaller complexity, and can be suitable for the communication data transmission under various low-power consumption and ultra-low SNR scenes.

Description

Shared data channel transmission method and equipment for wireless communication

Technical Field

The present invention relates generally to the field of wireless communications, and in particular, to a method and apparatus for transmitting a shared data channel for wireless communications of the internet of things.

Background

The core of the technology in the wide area internet of things is large coverage, low power consumption, large quantity of connection and low cost. The traditional 3G, 4G and other communication protocols are designed for high performance, and cannot be used for cost, power consumption and a large number of connections. In the prior art, lora and other communication protocols achieve the purposes of low cost and low power consumption to a part extent at the cost of performance reduction. However, due to the adoption of the relatively late spread spectrum technology (adopted in the third generation mobile communication before 20 years), the performance of the design is greatly reduced in complex environments, such as the level of coverage generally lower than 2km in urban environments. Whereas narrowband technologies such as SIGFOX are not robust against interference. Especially, the use of the existing channel transmission technology in wide-area internet of things communication cannot meet the processing requirements of wide-area internet of things coverage, less communication data and limited system overhead, so that resource waste and efficiency reduction in multi-carrier and multi-system communication are caused.

In internet of things communication at ultra-low SNR (e.g., -30 dB), a large amount of pilot overhead is required to receive data to complete channel estimation. And the optimized communication transmission based on the channel can effectively reduce the system overhead and the resource consumption.

Disclosure of Invention

The invention aims at: in order to reduce the communication overhead, the present invention provides a method for transmitting a shared data channel, and a method for wireless communication, and a corresponding channel transmission communication device, so as to achieve the effects of reducing the system overhead and reducing the resource consumption.

The technical scheme adopted by the invention is as follows:

a method for wireless communication, characterized in that after preprocessing data information based on a shared Data Channel (DCH), the shared data channel is used for carrying transmission of short messages and PDU data, the data information is mapped and loaded into data symbols according to a predefined data symbol format, and after secondary scrambling processing is performed, the data information is used for data transmission.

The data information is a source information character string, and comprises a short message character string and a PDU data character string; the data symbol represents a data transmission unit of wireless communication and is composed of control addition data.

The predefined DATA symbol format consists of a PCP control sequence and a DATA sequence; the PCP refers to a predefined variable-length variable cyclic prefix for interference rejection.

The preprocessing of the data information means that a source information character string is sequentially subjected to CRC (cyclic redundancy check), channel coding, bit level scrambling and modulation, and CRC parameter types selected by the CRC include a short message CRC type and a data packet CRC type.

Mapping and loading the DATA symbol according to a predefined DATA symbol format means that the preprocessed information DATA and PCP parameter DATA are mapped to the DATA sequence position and the PCP control sequence position in the DATA symbol respectively to obtain a loaded DATA symbol;

the length and the value of the PCP parameter data are determined according to the communication equipment and the physical layer channel of the current wireless communication.

The secondary scrambling processing means that the data symbol loaded with the data is scrambled again at symbol level, and corresponding filtering processing is performed according to the scrambling result, so as to obtain the data finally used for sending and transmitting.

The symbol-level scrambling includes sequentially multiplying the sample data within the data symbol with random sequence stream data.

The filtering process includes the steps of: firstly, the symbol data after phase modulation is subjected to unwrapping treatment, then interpolation and Gaussian filtering are carried out, and then the phase is restored to be within the phase of 0-2 pi.

A channel transmission apparatus for wireless communication, the apparatus comprising a processor for loading data symbols according to a predefined data symbol format map after preprocessing data information based on a shared data channel ((DCH) for carrying transmission of short messages and PDU data, and for data transmission after performing a secondary scrambling process.

In summary, due to the adoption of the technical scheme, the beneficial effects of the invention are as follows:

1. according to the embodiments provided by the invention, the predefined variable-length frequency domain equalization parameter PCP is introduced into the shared data channel in the channel transmission, so that more efficient modulation can be realized, and meanwhile, the channel estimation is finished according to different types of short messages or data, and the channel estimation quality is improved together.

2. According to the embodiments provided by the invention, the shared data channel can efficiently bear the transmission of the short message and PDU data, can perform correct demodulation and decoding under the very low condition, has smaller complexity, and can be suitable for communication data transmission under various low-power consumption and ultra-low SNR scenes.

Drawings

The invention will now be described by way of example and with reference to the accompanying drawings in which:

fig. 1 is a schematic diagram of a basic communication frame structure according to an embodiment of the present invention.

Fig. 2 is a flowchart of a method for sending information of a shared data channel DCH according to an embodiment of the present invention.

Fig. 3 is a schematic diagram of a data SDU format of a shared data channel DCH according to an embodiment of the present invention.

Fig. 4 is a schematic diagram of a resource mapping relationship on a data symbol in an embodiment of the present invention.

Fig. 5 is a schematic diagram of a phase filter processing flow in an embodiment of the invention.

Fig. 6 is a schematic diagram of a phase filtering result through a phase filtering process in an embodiment of the present invention.

Detailed Description

The embodiments will be described and illustrated in detail below with reference to the drawings,

any feature disclosed in this specification (including any accompanying claims, abstract) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. That is, each feature is one example only of a generic series of equivalent or similar features, unless expressly stated otherwise.

The following embodiments describe Wide area internet of things communication based on WIoTa (Wide-range Intetnet Of Things communicAtion protocol) protocol. In the mobile communication system, the user equipment may receive information from the base station in the downlink and transmit information to the base station in the uplink. The information transmitted or received by the user equipment may include data and various control information. And various types of physical channels may exist according to the type and purpose of information transmitted or received by the user equipment.

In addition, the configuration method and embodiments of the present invention may also be applied to various wireless access systems including CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access), and the like.

The meaning of the parameters which appear in the following examples is first described:

data symbol: the data symbol represents a data transmission unit of communication, and consists of PCP control plus data, and the number of Ts points is the power of 2;

frame: a frame, which is composed of 16 subframes, wherein each subframe starts to have a broadcast channel broadcast frame number;

subframe: the subframe can be uplink or downlink;

burst: the basic transmission unit, a Burst is the minimum transmission unit, can occupy one or more subframes according to the difference of BOOST Level, a basic transmission unit is fixedly formed by 8 time slots (slots);

slot: a slot, one slot is a unit occupied by the PD-CCCH and PU-CCCH physical layer channels.

BOOST level, which is to increase the coverage capacity, the higher the level, the more air interface resources are occupied (the more data are repeated), and the stronger the coverage capacity (BOOST);

AP is access point, access point;

DL/UL ratio: the uplink/downlink ratio, wherein the frame structure is a basic frame when DL/UL ratio=1, otherwise is an extended frame;

CRC, cyclic-redundancy check, cyclic redundancy check;

PCP: variable predefined CP, a predefined variable-length cyclic prefix.

PPS: predefined pilot sequence, a predefined pilot sequence.

Repetition group: the repetition group parameter RG refers to the basic symbol that the information bit (bit) occupies, and if one basic transmission unit contains more symbols, the repetition is performed in RG units. The common control channel uses rg=1 fixedly, and the data channel may use a large RG.

In this embodiment, wide area internet of things communication based on WIoTa adopts a TDD time division duplex mode, for example, one frame is fixed to 34.133/2ms, one subframe includes one Rx and one Tx (equal time), and 8 subframes are one frame.

Fig. 1 is a basic communication frame structure used in wide area communication internet of things (WIoTa), and an explanation of the frame structure may be used to help explain a physical layer channel structure.

Fig. 1 is a basic frame structure under the condition that the bandwidth of 1.25MHz (sampling rate of 1.92MHz, sampling interval of 0.5208 us), and the BOOST capability parameter BOOST is configured to 0.

In fig. 1, one frame (frame) is 273.0668 ms, which includes 16 subframes (subframes), and the uplink/downlink ratio DL/UL ratio is 1: and 1, the uplink subframes and the downlink subframes are staggered. The basic/minimum transmission unit of user data is one basic transmission unit. One basic transmission unit fixedly contains 8 time slots. As shown in fig. 1, when the BOOST is configured to be 0, one slot contains 8 data symbols, one data symbol is a basic transmission unit, the inside contains control and data, and the 8 slots form a basic transmission unit. Here, one downlink data symbol is 512Ts, and the number of sampling points of the uplink data symbol can be configured correspondingly according to specific network requirements (512 points, 256 points, 128 points, and 64 points).

In this embodiment, the uplink and downlink behaviors are staggered, each uplink basic transmission unit and each downlink basic transmission unit respectively correspond to one uplink subframe and one downlink subframe, the IoT terminal device accesses the communication network under the configuration condition of the coverage capability parameter BOOST, and the corresponding access point performs data transmission with each terminal device under the same BOOST configuration condition. Further, the uplink/downlink ratio DL/UL ratio and the coverage capability parameter BOOST are set, and different values of the coverage capability parameter BOOST are used for configuring the number of data symbols contained in the basic transmission unit, so that the control channel and the data channel are simultaneously subjected to the control of modulation coding and repetition times by the coverage capability parameter BOOST.

In wide area internet of things communication based on WIoTa, five basic physical layer channels are included, two of which are shared Data Channels (DCH), namely an uplink shared data channel (pu_dch) and a downlink shared data channel (pd_dch), the shared Data Channels (DCH) carry transmission of short messages and data PDUs, wherein the data PDUs (protocol data units PDU, protocol Data Unit) are data bits (bits) in the physical layer channels.

Fig. 2 is a flow chart of an information sending method based on a shared data channel DCH (including an uplink shared data channel (pu_dch) and a downlink shared data channel (pd_dch)) in wide area internet of things communication, and as shown in the flow chart, firstly, after information strings (bits) are sequentially subjected to CRC check, channel coding, bit level scrambling and modulation, the information strings are loaded into a data symbol (data symbol) together with a PCP as resource mapping (RE), and then subjected to symbol level repetition and symbol level scrambling, and finally, data sending is performed after phase filtering.

The channel transmission method can be used for channel data transmission and transmission of an uplink shared data channel (PU_DCH) and a downlink shared data channel (PD_DCH) in the wide area Internet of things.

The most basic unit of the shared DATA channel DCH is a basic transmission unit, if the short message is carried, the short message carrying channel (LD-SM-DATA-CH) in the logic channel only occupies one basic transmission unit, and the corresponding control is also in one basic transmission unit; if the SHARED DATA channel DCH carries a DATA packet PDU, a carrier DATA packet channel (LD-SHARED-DATA-CH) in the logical channel may occupy a plurality of consecutive basic transmission units, and the loading bits of the DATA packet are given in the header of the carrier DATA packet channel of the logical channel (in BYTE).

The CRC parameter types selected by the CRC check comprise a short message CRC type and a data packet CRC type, and the selection of the corresponding CRC parameters is consistent with whether the shared data channel DCH carries the short message or the data packet.

The PCP (variable predefined Cyclic-prefix) refers to a predefined variable-length cyclic prefix, and unlike the CP in LTE, the PCP improves the efficiency of the entire system by predefining sequence prefixes of different lengths on different channels. In one embodiment, the length of the PCP in the shared data channel DCH is generated and determined by the system PCP parameter generator and takes the form of a random constellation modulation sequence to facilitate estimation and transmission delay.

Heretofore, in order to overcome inter-symbol interference ISI specific to an OFDM system, LTE introduced a cyclic prefix concept, and LTE adopts CP-based initial synchronization, and its algorithm can only be a differential-based method, and it is required that a received signal-to-noise ratio is higher than about-10 dB. The PCP scheme provided by the embodiment of the invention can adopt a differential algorithm or a related algorithm, so that the signal-to-noise ratio of a received signal of a communication system can be as low as-30 dB, a wide area Internet of things communication terminal based on WIoTa can still normally work in some severe environments or extreme cases, and meanwhile, a base station can also cover a large range, thereby reducing the deployment and maintenance cost of the system.

The LENGTH value of the PCP in one embodiment is determined by a corresponding PCP LENGTH parameter (pcp_length).

For example, when PCP length parameter=0, the length of PCP takes a value of 4; when the uplink PCC length parameter=1, the length of the PCP takes a value of 8. The specific values are shown in the following table 1:

TABLE 1 PCP Length value

PCP Length parameter	Length value of PCP
		0	4
1	8
		2	16
3	32
		4	64
5	128
		6	256
7	512
		8	1024
9	2048

The shared data channel DCH occupies all time slots in the basic transmission unit, but if the downlink shared data channel PD_DCH and other common control channels coexist, the downlink shared data channel PD_DCH can be occupied by other common control channels to occupy part of resources; similarly, the uplink shared data channel pu_dch occupies the entire basic transmission unit, but in some cases, the corresponding slot resources are squeezed out by other common control channels of the user.

The constellation modulation of the shared data channel DCH may be 1/2Pi BPSK,1/4Pi QPSK or 1/8Pi 8psk.

Taking a logical shared DATA channel as an example, the format of the service DATA unit SDU is shown in fig. 3 below, and is composed of a SYSTEM domain, a LENGTH domain and a DATA domain, wherein the SYSTEM domain with a LENGTH of 1 bit is used to indicate whether it is a SYSTEM DATA packet or a user DATA packet, and the LENGTH domain with a LENGTH of 14 bits indicates the LENGTH (in terms of BYTE) of the whole SDU. The last DATA field is of variable length, the length of which is determined by the packet sent by the user.

The whole service data unit SDU is required to be added with a check bit CRC to become a protocol data unit PDU and is transmitted on an uplink or downlink shared data channel DCH. The uplink or downlink shared data channel DCH is encoded according to debugging, the number of information bits calculated through resource element mapping (resource elements) is required to be more than or equal to PDU of the data channel, and the excess part is subjected to cyclic repetition processing at symbol level.

In the shared data channel, the repeated group of values of the parameter RG may take the maximum RG value, which is determined by the corresponding parameter MAX-RG, and the relationship between the value of the parameter MAX-RG and the corresponding RG value is shown in table 2 below.

Table 2 relation table of MAX-RG values and RG values of repeated sets of parameters

Parameter MAX-RG	Repeated group parameter RG value
		0	1
1	2
		2	3
3	4

The code rate of the shared data channel DCH is determined by the code rate parameter of the system code, the code bit is scrambled at bit level after being generated, then mapped into a modulation symbol according to constellation, and the modulation symbol and PCP are generated together to generate a data symbol, and then repeated and secondary scrambling at symbol level (symbol) are carried out to obtain the data of the data channel of the last time slot for transmission.

The secondary scrambling processing refers to scrambling of symbol level of the data symbol loaded with specific data, and corresponding filtering processing is performed according to scrambling results, so as to obtain data finally used for sending and transmitting.

In one embodiment, the symbol-level scrambling method is as follows: firstly, generating a random character string, which can be generated by a Golden sequence generator to obtain a random sequence with a digit as the number of all data symbols in a frame; and then sequentially multiplying the sample point data in all the data symbols in the processed frame with the random sequence stream data after the bit modulation.

In the prior art, scrambling is usually performed on bit (bit) or QAM level, but in the embodiment of the invention, scrambling is performed on bit and symbol level, so that interference of the same frequency and the same system can be resisted, and meanwhile, the complexity increase of a receiver is small.

Before data transmission, filtering processing is needed, and a general shaping filter, such as root cosine filter, can bring fluctuation of signal amplitude, so that the setting of the constant amplitude of the whole Internet of things communication system is broken. Although GMSK modulation also performs gaussian filtering in the phase domain and then performs MSK phase accumulation and other operations, GMSK can obtain very good out-of-band suppression capability, but it can only work under signal modulation of BPSK, and the spectral efficiency cannot be effectively improved.

For this purpose, the present embodiment also provides an innovative phase filter that operates simultaneously with 1/2pi bpsk,1/4pi qpsk, and 1/8pi 8psk. The phase filter provided in this embodiment is performed in the phase domain, and the characteristic of the constant mode is not destroyed, but because the phase has the problem of 2pi inversion, it is difficult to directly perform phase filtering, so the processing flow of the phase filter is as shown in fig. 5 below:

firstly, the symbol after phase modulation is subjected to unwrapping processing, which is mainly used for processing the 2pi inversion problem of the phase, and the symbol range in the range of 0-2 pi is transformed into the linear range through the unwrapping operation, so that the phase is more continuous. Then interpolation (interpolation) and Gaussian filter (Gaussian filter) are carried out, then the phase of 0-2 pi is converted through Wrap processing, and finally a voltage-controlled oscillation circuit of a radio frequency end is pushed.

As shown in fig. 6 below, the phase filtering process is followed by the input phase, the unwrapped phase, the interpolated phase, and the wrap recovered phase filtering results.

Embodiment 3 provides an apparatus for wireless communication, the apparatus comprising a processor configured to pre-process data information based on a shared data channel ((DCH), then load the pre-processed data information into data symbols according to a predefined data symbol format map, and then perform a secondary scrambling process for data transmission.

In summary, the embodiments of the present invention provide a method for transmitting information based on a shared Data Channel (DCH) in wide area internet of things communication and a corresponding wireless communication device. Based on the information sending method and the communication device in the embodiments, the data communication of the Internet of things with high efficiency, stability and low power consumption can be completed in the communication of the wide-area wireless Internet of things.

All of the features disclosed in this specification, or all of the steps in a method or process disclosed, may be combined in any combination, except for mutually exclusive features and/or steps.

The invention is not limited to the specific embodiments described above. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification, as well as to any novel one, or any novel combination, of the steps of the method or process disclosed.

Claims

1. A method for wireless communication, characterized in that after preprocessing data information based on a shared Data Channel (DCH), the data information is mapped and loaded into data symbols according to a predefined data symbol format, and the data symbols loaded with specific data are used for data transmission after repeated and secondary scrambling processing at symbol level, and the shared data channel is used for carrying short message and PDU data transmission;

the preprocessing of the data information is to sequentially subject an information character string to CRC (cyclic redundancy check), channel coding, bit level scrambling and modulation;

the data symbol represents a data transmission unit of wireless communication and consists of control addition data; the predefined DATA symbol format consists of a PCP control sequence and a DATA sequence; the PCP refers to a predefined variable-length variable cyclic sequence prefix for interference rejection on different channels; the length and the value of the PCP parameter data are determined according to the communication equipment and the physical layer channel of the current wireless communication;

the scrambling method at the symbol level is as follows: firstly, generating a random character string to obtain a random sequence with a digit as the number of all data symbols in a frame; and then sequentially multiplying the sample point data in all the data symbols in the processed frame with the random sequence stream data after the bit modulation.

2. The method of claim 1, wherein the data information is a source information string comprising a short message string and a PDU data string.

3. A method for wireless communication according to claim 1, wherein the preprocessing of the data information means that the source information string is sequentially subjected to CRC check, channel coding, bit level scrambling and modulation, and the CRC parameter type selected by the CRC check includes a short message CRC type and a packet CRC type.

4. A method for wireless communication as defined in claim 3, wherein,

5. The method of claim 1, wherein the performing secondary scrambling refers to performing symbol-level scrambling again on the data symbol loaded with data, and performing corresponding filtering according to the scrambling result to obtain data finally used for transmission and reception.

6. A method for wireless communication as defined in claim 5, wherein the symbol-level scrambling comprises sequentially multiplying sample data within data symbols with random sequence stream data.

7. The method for wireless communication of claim 6, wherein the filtering process comprises the steps of: firstly, the symbol data after phase modulation is subjected to unwrapping treatment, then interpolation and Gaussian filtering are carried out, and then the phase is restored to be within the phase of 0-2 pi.

8. A channel transmission device for a method of wireless communication according to any of the claims 1-7, characterized in that the device comprises a processor for pre-processing data information based on a shared Data Channel (DCH) for carrying transmission of short messages and PDU data, loading into data symbols according to a predefined data symbol format mapping, and for data transmission after a secondary scrambling process.