CN112217597B - Method and equipment for demodulating physical broadcast channel PBCH - Google Patents

Method and equipment for demodulating physical broadcast channel PBCH Download PDF

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CN112217597B
CN112217597B CN201910619704.XA CN201910619704A CN112217597B CN 112217597 B CN112217597 B CN 112217597B CN 201910619704 A CN201910619704 A CN 201910619704A CN 112217597 B CN112217597 B CN 112217597B
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pbch
llr value
frame
radio frame
combined
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CN112217597A (en
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金晓成
黄剑华
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Datang Mobile Communications Equipment Co Ltd
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Datang Mobile Communications Equipment Co Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0036—Systems modifying transmission characteristics according to link quality, e.g. power backoff arrangements specific to the receiver

Abstract

The application provides a method and equipment for demodulating a physical broadcast channel PBCH (physical broadcast channel), which are used for improving the demodulation performance of the PBCH. The method comprises the following steps: receiving a first wireless frame sent by network equipment; determining a difference between information carried by a first PBCH in the first radio frame and information carried by a second PBCH in a second radio frame if the lower three bits of a System Frame Number (SFN) of the first radio frame are not zero; wherein the second radio frame is a frame received before the first radio frame within a Transmission Time Interval (TTI), and the lower three bits of the SFN of the second radio frame are zero; determining a first log-likelihood ratio (LLR) value for the first wireless frame based on the difference; combining the first LLR value with a second LLR value of the second wireless frame to obtain a combined first combined LLR value; and demodulating the first PBCH according to the first combined LLR value.

Description

Method and equipment for demodulating physical broadcast channel PBCH
Technical Field
The present application relates to the field of communications technologies, and in particular, to a method and an apparatus for demodulating a physical broadcast channel PBCH.
Background
With the continuous development of mobile services, people have higher and higher requirements on the transmission rate of wireless communication, and in a fifth generation mobile communication technology (5G) System, before a User Equipment (UE) accesses a certain network device, the User Equipment needs to acquire System Information (SI) of the network device to know how the network device is configured so as to correctly work in the network device.
In LTE, a network device sends a Master Information Block (MIB) to all UEs in a coverage area of the network device through a Broadcast Channel (PBCH), where the MIB Information includes the highest 8 bits in a System Frame Number (SFN) of 10bits (bits) and is used for time alignment between the UE and the network device.
Since the PBCH bearer includes the SFN, and the SFN is different at different time instants, resulting in different sequences (information of the PBCH bearer, a series of sequences formed by scrambling, encoding, etc.), which may result in that soft values demodulated by PBCH in different SFNs cannot be combined, thereby resulting in lower demodulation performance of PBCH.
Disclosure of Invention
The embodiment of the application provides a method and equipment for demodulating a physical broadcast channel PBCH (physical broadcast channel), which are used for improving the demodulation performance of the PBCH.
In a first aspect, the present application provides a method for demodulating a physical broadcast channel PBCH, including:
receiving a first wireless frame sent by network equipment;
determining a difference between information carried by a first PBCH in the first radio frame and information carried by a second PBCH in a second radio frame if the lower three bits of a System Frame Number (SFN) of the first radio frame are not zero; wherein the second radio frame is a frame received before the first radio frame within a Transmission Time Interval (TTI), and the lower three bits of the SFN of the second radio frame are zero;
determining a first LLR value for the first wireless frame based on the difference;
combining the first LLR value with a second LLR value of the second wireless frame to obtain a combined first combined LLR value;
and demodulating the first PBCH according to the first combined LLR value.
In this embodiment, when the lower three bits of the received SFN of the first radio frame are not zero, a difference between information carried by a PBCH in the first radio frame and information carried by a second PBCH in the second radio frame may be determined, and an influence of the difference on an LLR value of the first radio frame may be eliminated, so that the first LLR value may be combined with the second LLR value of the second radio frame to improve demodulation performance of the PBCH.
In one possible design, if the demodulation result for the first PBCH is an error, the method further includes:
receiving a third wireless frame sent by the network equipment;
determining a difference between information carried by a third PBCH in the third radio frame and information carried by the second PBCH if the lower three bits of the SFN of the third radio frame are not zero;
determining a third LLR value of the third radio frame according to the difference;
combining the third LLR value with the first combined LLR value to obtain a combined second combined LLR value;
and demodulating the second PBCH according to the second combined LLR value until the last radio frame received in the TTI.
In this embodiment of the present application, when demodulation of the first PBCH fails using the first combined LLR value, the third radio frame is received, and when the lower three bits of the third radio frame are not zero, according to a difference between information carried by the third PBCH in the third radio frame and information carried by the second PBCH in the second radio frame, an influence of the difference on an LLR value of the third radio frame is eliminated, so that the third LLR value of the third radio frame can be combined with the second combined LLR value, the third PBCH is demodulated according to the second combined LLR value, and if demodulation is wrong, LLR value combination is continued according to the above method until the last radio frame in the TTI is received.
In one possible design, determining a difference between information carried by a first PBCH in the first radio frame and information carried by a second PBCH in a second radio frame includes:
zeroing the rest positions except the lower three bits in the information bits carried by the first PBCH to obtain the first PBCH carrying information ynN is used for representing the value of the SFN of the first PBCH;
according to ynDetermining a difference between information carried by the first PBCH and information carried by the second PBCH to be H (G (F (y)) in a first time periodn)))；
Wherein H () is used to characterize as ynFunction of scrambling, G () being for characterizing as ynFunction for increasing cyclic redundancy, F () being for characterizing as ynA function of the encoding.
In one possible design, determining the first LLR value for the first wireless frame based on the difference comprises:
demodulating the first PBCH to obtain an LLR value;
according to the LLR value and the H (G (F (y))n) ) to determine a first LLR value for the first wireless frame.
In one possible design of the system,
the first LLR ═ LLR (1-2 × (G (F (y)) H (G)) and (G) (G (y)) and (G) (G) and (G) (G) and (c) and (b) and (c) and (b) and (c) respectively) and (c) respectively)n))))*(1-2*H(G(F(y0))))；
Wherein, y0Values for characterizing SFNWhen the number of PBCH messages is zero.
In a second aspect, an embodiment of the present application further provides a terminal device, including:
a memory to store instructions;
a processor for reading the instructions in the memory, performing the following processes:
controlling a receiver to receive a first wireless frame sent by network equipment;
determining a difference between information carried by a first PBCH in the first radio frame and information carried by a second PBCH in a second radio frame if the lower three bits of a System Frame Number (SFN) of the first radio frame are not zero; wherein the second radio frame is a frame received before the first radio frame within a Transmission Time Interval (TTI), and the lower three bits of the SFN of the second radio frame are zero;
determining a first log-likelihood ratio (LLR) value for the first wireless frame based on the difference;
combining the first LLR value with a second LLR value of the second wireless frame to obtain a combined first combined LLR value;
and demodulating the first PBCH according to the first combined LLR value.
In one possible design, when the demodulation result for the first PBCH is in error, the processor is further configured to:
controlling the receiver to receive a third wireless frame sent by the network equipment;
determining a difference between information carried by a third PBCH in the third radio frame and information carried by the second PBCH if the lower three bits of the SFN of the third radio frame are not zero; determining a third LLR value of the third wireless frame according to the difference;
combining the third LLR value with the first combined LLR value to obtain a combined second combined LLR value;
and demodulating the third PBCH according to the second combined LLR value until the last radio frame received in the TTI.
In one possible design, when the processor determines a difference between information carried by a first PBCH in the first radio frame and information carried by a second PBCH in a second radio frame, it is specifically configured to:
zeroing the rest positions except the lower three bits in the information bits carried by the first PBCH to obtain the first PBCH carrying information ynN is used for representing the value of the SFN of the first PBCH;
according to ynDetermining a difference between information carried by the first PBCH and information carried by the second PBCH to be H (G (F (y)) in a first time periodn)))；
Wherein H () is used to characterize as ynFunction of scrambling, G () being for characterizing as ynFunction for increasing cyclic redundancy, F () being for characterizing as ynA function of the encoding.
In one possible design, when the processor determines the first LLR value of the first wireless frame according to the difference, the method is specifically configured to:
according to the LLR value obtained after demodulating the first PBCH and the H (G (F (y))n) ) to determine a first LLR value for the first wireless frame.
In one possible design of the system,
the first LLR ═ LLR (1-2 × (G (F (y)) H (G)) and (G) (G (y)) and (G) (G) and (G) (G) and (c) and (b) and (c) and (b) and (c) respectively) and (c) respectively)n))))*(1-2*H(G(F(y0))))；
Wherein, y0And the PBCH carried information when the value for representing the SFN is zero.
In a third aspect, an embodiment of the present application further provides a terminal device, including:
a receiving module, configured to receive a first wireless frame sent by a network device;
a determining module, configured to determine a difference between information carried by a first PBCH in the first wireless frame and information carried by a second PBCH in a second wireless frame when the lower three bits of a system frame number SFN of the first wireless frame are not zero; wherein the second radio frame is a frame received before the first radio frame within a Transmission Time Interval (TTI), and the lower three bits of the SFN of the second radio frame are zero; and determining a first log-likelihood ratio (LLR) value of the first wireless frame according to the difference;
a merging module, configured to merge the first LLR value with a second LLR value of the second radio frame to obtain a merged first merged LLR value;
a demodulation module, configured to demodulate the first PBCH according to the first combined LLR value.
In one possible design, when the demodulation result for the first PBCH is an error, the receiving module is further configured to:
receiving a third wireless frame sent by the network equipment;
the determining module is further configured to determine a difference between information carried by a third PBCH in the third radio frame and information carried by the second PBCH when the lower three bits of the SFN of the third radio frame are not zero; determining a third LLR value of the third wireless frame according to the difference;
the merging module is further configured to:
combining the third LLR value with the first combined LLR value to obtain a combined second combined LLR value;
the demodulation module is further configured to:
and demodulating the third PBCH according to the second combined LLR value until the last radio frame received in the TTI.
In one possible design, when the determining module determines the difference between the information carried by the first PBCH in the first radio frame and the information carried by the second PBCH in the second radio frame, it is specifically configured to:
zeroing the rest positions except the lower three bits in the information bits carried by the first PBCH to obtain the first PBCH carrying information ynN is used for representing the value of the SFN of the first PBCH;
according to ynDetermining a difference between information carried by the first PBCH and information carried by the second PBCH to be H (G (F (y)) in a first time periodn)))；
Wherein H () is used to characterize as ynFunction of scrambling, G () being for characterizing as ynIncrease the circulationRedundant function, F () for characterizing as ynA function of the encoding.
In one possible design, when the determining module determines the first LLR value of the first wireless frame according to the difference, the determining module is specifically configured to:
according to the LLR value obtained after demodulating the first PBCH and the H (G (F (y))n) ) to determine a first LLR value for the first wireless frame.
In one possible design of the system,
the first LLR ═ LLR (1-2 × (G (F (y)) H (G)) and (G) (G (y)) and (G) (G) and (G) (G) and (c) and (b) and (c) and (b) and (c) respectively) and (c) respectively)n))))*(1-2*H(G(F(y0))))；
Wherein, y0And the PBCH carried information when the value for representing the SFN is zero.
A fourth aspect provides a computer storage medium storing computer software instructions for a terminal device as described in the second aspect or a terminal device as described in the third aspect and comprising a program designed for a terminal device to perform any one of the possible designs of the first aspect or the first aspect.
In a fifth aspect, the present application provides a computer program product, which when invoked by a computer causes the computer to perform the method as designed by any one of the first aspect and the first aspect.
Drawings
Fig. 1A and 1B are schematic diagrams of an encoding process and a decoding process of PBCH in the prior art;
FIG. 2 is a schematic diagram of an application scenario provided herein;
fig. 3 is a schematic flowchart of a method for demodulating a physical broadcast channel PBCH according to the present application;
fig. 4A and fig. 4B are schematic diagrams illustrating comparison between the demodulation method of the physical broadcast channel PBCH provided in the present application and the demodulation method of the PBCH in the prior art;
fig. 5 is a schematic structural diagram of a terminal device provided in the present application;
fig. 6 is a schematic structural diagram of another terminal device provided in the embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application.
Hereinafter, some terms in the embodiments of the present application are explained to facilitate understanding by those skilled in the art.
(1) A network device, e.g., including a base station (e.g., access point), can refer to a device in an access network that communicates over the air-interface, through one or more sectors, with wireless terminal devices. The base station may be configured to interconvert received air frames and IP packets as a router between the user equipment and the rest of the access network, which may include an IP network. The base station may also coordinate management of attributes for the air interface. For example, the base station may include an evolved Node B (NodeB, eNB, or e-NodeB) in a Long Term Evolution (LTE) system or an evolved LTE system (LTE-Advanced, LTE-a), or may also include a next generation Node B (NG-NB) in a 5G system, which is not limited in the embodiments of the present invention.
(2) Terminal equipment, including devices that provide voice and/or data connectivity to a user, may include, for example, handheld devices with wireless connection capability or processing devices connected to wireless modems. The terminal device may communicate with a core Network via a Radio Access Network (RAN), and exchange voice and/or data with the RAN. The Terminal Device may include a User Equipment (UE), a wireless Terminal Device, a Mobile Terminal Device, a Subscriber Unit (Subscriber Unit), a Subscriber Station (Subscriber Station), a Mobile Station (Mobile), a Remote Station (Remote Station), an Access Point (AP), a Remote Terminal Device (Remote Terminal), an Access Terminal Device (Access Terminal), a User Terminal Device (User Terminal), a User Agent (User Agent), or a User Equipment (User Device), etc. For example, mobile phones (or so-called "cellular" phones), computers with mobile terminal equipment, portable, pocket, hand-held, computer-included or vehicle-mounted mobile devices, smart wearable devices, and the like may be included. For example, Personal Communication Service (PCS) phones, cordless phones, Session Initiation Protocol (SIP) phones, Wireless Local Loop (WLL) stations, Personal Digital Assistants (PDAs), smart watches, smart helmets, smart glasses, smart bracelets, and the like. Also included are constrained devices, such as devices that consume less power, or devices that have limited storage capabilities, or devices that have limited computing capabilities, etc. Including, for example, bar codes, Radio Frequency Identification (RFID), sensors, Global Positioning Systems (GPS), laser scanners, and other information sensing devices.
(3) The System Frame Number (SFN) may be represented by consecutive N bits, each bit may be 0 or 1, the position of each bit in the N bits is referred to as a bit, and the value of the SFN may be from 0 to 2N. For example, when the length of the system frame number is 10bits, the system frame number 0000000010 represents the wireless system frame 2, where the bit on the 9 th bit is 1, which can be understood as the 9 th bit is 1.
In a 5G communication system, a Transmission Time Interval (TTI) of a PBCH is 80ms, each TTI includes 8 radio frames, and if a period of the PBCH is 10ms, a base station transmits a system frame number of the radio frame by transmitting the PBCH in radio frames 0 to 7, respectively. For example, the system frame number of the radio frame 0 is 0000000000, the system frame number of the radio frame 1 is 0000000001, the system frame number of the radio frame 2 is 0000000010, the system frame number of the radio frame 3 is 0000000011, the system frame number of the radio frame 4 is 0000000100, the system frame number of the radio frame 4 is 0000000100, the system frame number of the radio frame 5 is 0000000101, the system frame number of the radio frame 6 is 0000000110, and the system frame number of the radio frame 7 is 0000000111. If the PBCH period is 20ms, the base station transmits the PBCH transmission radio frame in the radio frames 0, 2,4, and 6, respectively. For example, the system frame number of radio frame 0 is 0000000000, the system frame number of radio frame 2 is 0000000010, the system frame number of radio frame 4 is 0000000100, and the system frame number of radio frame 6 is 0000000110.
(4) In addition, the term "and/or" herein is only one kind of association relationship describing an associated object, and means that there may be three kinds of relationships, for example, a and/or B, which may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship, unless otherwise specified. Moreover, in the description of the embodiments of the present invention, the terms "first," "second," and the like are used for descriptive purposes only and not for purposes of indicating or implying relative importance, nor for purposes of indicating or implying order.
The technical background of the embodiments of the present application is described below.
Referring to fig. 1A, a coding process of PBCH includes a first scrambling, adding Cyclic Redundancy Check (CRC), channel coding, rate matching, a second scrambling, and Quadrature Phase Shift Keying (QPSK) modulation. Where the added CRC may be a 16-bit cyclic redundancy code, the channel coding may use tail-biting convolutional coding or Polar (Polar) coding, rate matching including sub-block interleaving, bit selection, and pruning.
Correspondingly, please refer to fig. 1B, which shows a PBCH demodulation process, including QPSK demodulation, descrambling corresponding to the second scrambling, rate de-matching, channel decoding, descrambling corresponding to the first scrambling, and CRC check.
In the prior art, for example, the PBCH period is 20 milliseconds (ms), then 4 radio frames are received by the terminal device in one TTI80ms, and the terminal device demodulates the PBCH of the radio frames individually. And at different time when 4 radio frames are received, SFNs carried by PBCH are different, so that soft values after rate de-matching at different time within one TTI cannot be combined, and when the soft values after rate de-matching cannot be combined, combining gain cannot be obtained, so that the demodulation performance of PBCH cannot be improved.
In view of this, the present application provides a method for demodulating PBCH of physical broadcast channel, which may determine a difference between information carried by PBCH in a first radio frame and information carried by second PBCH in a second radio frame when lower three bits of SFN of the received first radio frame are not zero, and eliminate an influence of the difference on an LLR value of the first radio frame, so that the first LLR value can be combined with the second LLR value of the second radio frame to improve demodulation performance of PBCH.
Please refer to fig. 2, which is an application scenario of the embodiment of the present application. In fig. 2 a base station and terminal devices within range of the base station are included. The base station sends MIB to the terminal equipment within the coverage of the base station through a broadcast channel, and the MIB is used for time alignment between the terminal equipment and the base station.
In the following description, the technical solution provided by the present application is applied to the application scenario shown in fig. 2 as an example, and a network device is a base station as an example.
Referring to fig. 3, a method for demodulating PBCH in a physical broadcast channel according to an embodiment of the present application is described as follows:
s301: the base station sends a first wireless frame to the terminal equipment, and correspondingly, the terminal equipment receives the first wireless frame sent by the base station.
After receiving the first wireless frame sent by the base station, the terminal device descrambles the PBCH in the first wireless frame correspondingly by scrambling for the second time, then performs de-rate matching, and after performing de-rate matching on the PBCH, obtains an LLR value of the first wireless frame and obtains the lower three bits of the SFN of the first wireless frame.
After obtaining the third bit of the SFN of the first wireless frame, step S302 is executed: determining a difference between information carried by a first PBCH in the first radio frame and information carried by a second PBCH in a second radio frame if the lower three bits of a System Frame Number (SFN) of the first radio frame are not zero; the second radio frame is a frame received before the first radio frame in a Transmission Time Interval (TTI), and the lower three bits of the SFN of the second radio frame are zero.
In the embodiment of the present application, the PBCH period may be 20ms or 10 ms. If the value of SFN is represented by n, and when the period of PBCH is 20ms, 4 radio frames, namely radio frame 0, radio frame 2, radio frame 4, and radio frame 6, are transmitted in one TTI, the value of n may be 2,4, and 6; when the PBCH period is 10ms, 8 radio frames are transmitted in one TTI, which are radio frames 0 to 7, and the value of n may be 1 to 7.
In the following description, the PBCH period is 20 ms. Assuming that SFN is 0, PBCH carries x information1When the base station sends PBCH to the terminal equipment, the base station scrambles the information carried by PBCH for the first time, adds CRC and carries out Polar coding to obtain H (G (F (x)1))). Wherein, H () is used to characterize the scrambling function, G () is used to characterize the adding CRC function, F () is used to characterize the coding function, and the functions H (), G (), F () are all functions related to modulo-2 addition in principle, F (x), G (x), H (x) satisfy the following relations respectively:
F(mod(x1+x2,2))＝mod(F(x1)+F(x2),2)
G(mod(x1+x2,2))＝mod(G(x1)+G(x2),2)
H(mod(x1+x2,2))＝mod(H(x1)+H(x2),2)
in the 5G communication system, the PBCH in each TTI carries only the different contents of the lower three bits of the SFN, and the other bearers have the same contents, so in this embodiment, in the case of SFN ═ n, the difference between the information carried by the first PBCH of the first radio frame and the information carried by the second PBCH of the second radio frame is the lower three bits of the SNF. How to determine the difference between the information carried by the first PBCH of the first radio frame and the information carried by the second PBCH of the second radio frame includes, in a specific implementation process, the following steps:
zeroing the rest positions except the lower three bits in the information bits carried by the first PBCH to obtain the first PBCH carrying information ynN is used for representing the value of the SFN of the first PBCH;
according to ynDetermining a difference between information carried by the first PBCH and information carried by the second PBCH to be H (G (F (y)) in a first time periodn)))；
Wherein H () is used to characterize as ynFunction of scrambling, G () being for characterizing as ynFunction for increasing cyclic redundancy, F () being for characterizing as ynA function of the encoding.
Based on the above description, it can be known that the content of PBCH bearer in each TTI is only different in the lower three bits of SFN, and the content of other bearers is the same. Therefore, the rest of the information bits carried by the first PBCH except for the lower three bits can be set to zero, and then the information carried by the first PBCH can be set to ynThat means, the information carried by the first PBCH may be denoted as x under SFN ═ nn＝mod(x1+yn). Therefore, when SFN is equal to n, the result of the first scrambling, CRC addition and Polar coding is: h (G (F (x))n)))＝mod(H(G(F(x1)))+H(G(F(yn))),2). Wherein, H (G (F (y))n) Etc.) corresponds to performing an additional scrambling operation on Polar encoding results at SFN-0. Therefore, if H (G (F (y)) can be removed by descrambling at the time of demodulationn) ) the demodulated soft values at different times can be combined.
Therefore, in the specific implementation process, the other positions of the first PBCH except the lower three bits of the SFN are set to be zero to obtain ynThen, for ynPerforming first scrambling, adding CRC, Polar coding to obtain H (G (F (y))n) That is, the difference between information carried by the first PBCH of the first radio frame and information carried by the second PBCH of the second radio frame).
In this embodiment of the application, after determining the difference between the information carried by the first PBCH of the first radio frame and the information carried by the second PBCH of the second radio frame, step S303 is executed: determining a first LLR value for the first wireless frame based on the difference;
after determining a difference between information carried by the first PBCH and information carried by the second PBCH, determining a first LLR value for the first wireless frame according to the determined difference. In the specific implementation process, the specific implementation process of step S303 includes the following steps:
according to the LLR value obtained after demodulating the first PBCH and the H (G (F (y))n) ) to determine a first LLR value for the first wireless frame.
In concrete embodimentsIn the present process, the first LLR ═ LLR (1-2 × (H) (G (F (y)) is obtainedn))))*(1-2*H(G(F(y0))))；
Wherein, y0And the PBCH carried information when the value for representing the SFN is zero.
S304: combining the first LLR value with a second LLR value of the second wireless frame to obtain a combined first combined LLR value;
and after the first LLR value of the first wireless frame is determined, combining the first LLR value with the second LLR value of the second wireless frame to obtain a combined first combined LLR value.
S305: and demodulating the first PBCH according to the first combined LLR value.
And after the combined first combined LLR value is obtained, demodulating the first PBCH by using the first combined LLR value. In a specific implementation process, the first combined LLR value may be input to the PBCH channel decoder, so as to obtain a PBCH channel decoding result corresponding to the first combined LLR. And after the PBCH decoding result corresponding to the first combination LLR value is obtained, performing CRC check on the PBCH decoding result corresponding to the first combination LLR value again.
In this embodiment of the present application, when the CRC check is successful, it may be determined that the PBCH has been successfully demodulated in the current generic time interval, and the PBCH demodulation may be released, and if the CRC check fails, in this embodiment of the present application, the method further includes:
receiving a third wireless frame sent by the network equipment;
determining a difference between information carried by a third PBCH in the third radio frame and information carried by the second PBCH if the lower three bits of the SFN of the third radio frame are not zero;
determining a third LLR value of the third radio frame according to the difference;
combining the third LLR value with the first combined LLR value to obtain a combined second combined LLR value;
and demodulating the third PBCH according to the second combined LLR value until the last radio frame received in the TTI.
In this embodiment, the terminal device receives a third radio frame sent by the base station, determines whether lower three bits of an SFN of a third PBCH of the third radio frame are zero, if not, determines a difference between information carried by the third PBCH of the third radio frame and information carried by a second PBCH of the second radio frame, determines a third LLR value of the third radio frame according to the determined difference, and then combines the third LLR value with the first combined LLR value to obtain a second combined LLR value, and inputs the second combined LLR value to the PBCH channel decoder, thereby obtaining a PBCH channel decoding result corresponding to the second combined LLR value. And after the PBCH decoding result corresponding to the second combined LLR value is obtained, performing CRC check on the PBCH decoding result corresponding to the second combined LLR value again, if the CRC check is successful, judging that the PBCH is successfully demodulated in the current transmission time interval, releasing the PBCH demodulation, and if the CRC check is failed, receiving the next radio frame until the last radio frame in the current transmission time interval.
It should be noted that, the above description of the scheme provided in the present application mainly takes the PBCH period as 20ms as an example, and is also applicable to the PBCH period as 10ms or other periods, which is not described herein again.
In the embodiment of the present application, since LLR values at different SFN times may be combined, demodulation performance of PBCH may be improved, and a specific simulation example is combined to compare performance gains of the technical solutions provided in the present application compared with the technical solutions in the prior art.
The simulation conditions are assumed to be Additive White Gaussian Noise (AWGN), 1 × 2 antenna, PBCH period is 20ms, Subcarrier Spacing (SCS), Signal to Noise Ratio (SNR) on the abscissa, and PBCH bit Error rate (Block Error rate, BER) on the ordinate. Fig. 4A is a comparison of BLER performance of the present application versus the prior art under ideal channel estimation, where the right curve is BLER performance of the present application and the left curve is BLER performance of the prior art, which is improved by about 3dB over the prior art; fig. 4B is a comparison of BLER performance of the present application with that of the prior art under actual channel estimation, where the right curve is BLER performance of the present application and the left curve is BLER performance of the prior art, which is improved by about 1.5dB over the prior art.
Referring to fig. 5, based on the same inventive concept, an embodiment of the present application provides a terminal device 500, including:
a receiving module 501, configured to receive a first wireless frame sent by a network device;
a determining module 502, configured to determine, when the lower three bits of a system frame number SFN of the first wireless frame are not zero, a difference between information carried by a first PBCH in the first wireless frame and information carried by a second PBCH in a second wireless frame; wherein the second radio frame is a frame received before the first radio frame within a Transmission Time Interval (TTI), and the lower three bits of the SFN of the second radio frame are zero; and determining a first log-likelihood ratio (LLR) value of the first wireless frame according to the difference;
a merging module 503, configured to merge the first LLR value with the second LLR value of the second radio frame to obtain a merged first merged LLR value;
a demodulation module 504, configured to demodulate the first PBCH according to the first combined LLR value.
In one possible design, when the demodulation result of the first PBCH is an error, the receiving module 501 is further configured to:
receiving a third wireless frame sent by the network equipment;
the determining module 502 is further configured to:
determining a difference between information carried by a third PBCH in the third radio frame and information carried by the second PBCH when the lower three bits of the SFN of the third radio frame are not zero; determining a third LLR value of the third wireless frame according to the difference;
the merge module 503 is further configured to:
combining the third LLR value with the first combined LLR value to obtain a combined second combined LLR value;
the demodulation module 504 is further configured to:
and demodulating the third PBCH according to the second combined LLR value until the last radio frame received in the TTI.
In one possible design, when the determining module 502 determines the difference between the information carried by the first PBCH in the first radio frame and the information carried by the second PBCH in the second radio frame, it is specifically configured to:
zeroing the rest positions except the lower three bits in the information bits carried by the first PBCH to obtain the first PBCH carrying information ynN is used for representing the value of the SFN of the first PBCH;
according to ynDetermining a difference between information carried by the first PBCH and information carried by the second PBCH to be H (G (F (y)) in a first time periodn)))；
Wherein H () is used to characterize as ynFunction of scrambling, G () being for characterizing as ynFunction for increasing cyclic redundancy, F () being for characterizing as ynA function of the encoding.
In one possible design, when the determining module determines the first LLR value of the first wireless frame according to the difference, the determining module is specifically configured to:
according to the LLR value obtained after demodulating the first PBCH and the H (G (F (y))n) ) to determine a first LLR value for the first wireless frame.
In one possible design of the system,
the first LLR ═ LLR (1-2 × (G (F (y)) H (G)) and (G) (G (y)) and (G) (G) and (G) (G) and (c) and (b) and (c) and (b) and (c) respectively) and (c) respectively)n))))*(1-2*H(G(F(y0))))；
Wherein, y0And the PBCH carried information when the value for representing the SFN is zero.
Referring to fig. 6, an embodiment of the present application further provides a terminal device 600, where in an implementation of the terminal device, the terminal device includes a memory 601, a processor 602, and a receiver 603, and the memory 601 and the receiver 603 are coupled to the processor 602. The processor 602 may be a Central Processing Unit (CPU), an application-specific integrated circuit (ASIC), one or more integrated circuits for controlling program execution, a baseband chip, or the like. The number of memories may be one or more, and the memories may be read-only memories (ROMs), Random Access Memories (RAMs), or disk memories, etc.
By programming the processor 602, the code corresponding to the foregoing demodulation method of the physical broadcast channel PBCH may be solidified into a chip, so that the chip can perform the following steps when running:
receiving, by a receiver 603, a first wireless frame sent by a network device;
determining a difference between information carried by a first PBCH in the first radio frame and information carried by a second PBCH in a second radio frame if the lower three bits of a System Frame Number (SFN) of the first radio frame are not zero; wherein the second radio frame is a frame received before the first radio frame within a Transmission Time Interval (TTI), and the lower three bits of the SFN of the second radio frame are zero;
determining a first log-likelihood ratio (LLR) value for the first wireless frame based on the difference;
combining the first LLR value with a second LLR value of the second wireless frame to obtain a combined first combined LLR value;
and demodulating the first PBCH according to the first combined LLR value.
In one possible design, if the demodulation result for the first PBCH is an error, the processor 602 is further configured to:
receiving, by the receiver 603, a third wireless frame sent by the network device;
determining a difference between information carried by a third PBCH in the third radio frame and information carried by the second PBCH if the lower three bits of the SFN of the third radio frame are not zero;
determining a third LLR value of the third radio frame according to the difference;
combining the third LLR value with the first combined LLR value to obtain a combined second combined LLR value;
and demodulating the third PBCH according to the second combined LLR value until the last radio frame received in the TTI.
In one possible design, when the processor 602 determines the difference between the information carried by the first PBCH in the first radio frame and the information carried by the second PBCH in the second radio frame, it is specifically configured to:
zeroing the rest positions except the lower three bits in the information bits carried by the first PBCH to obtain the first PBCH carrying information ynN is used for representing the value of the SFN of the first PBCH;
according to ynDetermining a difference between information carried by the first PBCH and information carried by the second PBCH to be H (G (F (y)) in a first time periodn)))；
Wherein H () is used to characterize as ynFunction of scrambling, G () being for characterizing as ynFunction for increasing cyclic redundancy, F () being for characterizing as ynA function of the encoding.
In one possible design, when the processor determines the first LLR value of the first wireless frame according to the difference, the method is specifically configured to:
according to the LLR value obtained after demodulating the first PBCH and the H (G (F (y))n) ) to determine a first LLR value for the first wireless frame.
In one possible design of the system,
the first LLR ═ LLR (1-2 × (G (F (y)) H (G)) and (G) (G (y)) and (G) (G) and (G) (G) and (c) and (b) and (c) and (b) and (c) respectively) and (c) respectively)n))))*(1-2*H(G(F(y0))))；
Wherein, y0And the PBCH carried information when the value for representing the SFN is zero.
Embodiments of the present application also provide a computer storage medium, which may include a memory, where the memory may store a program, and the program includes all the steps executed by the electronic device as described in the method embodiment shown in fig. 3.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims (10)

1. A method for demodulating a Physical Broadcast Channel (PBCH), comprising:
receiving a first wireless frame sent by network equipment;
if the lower three bits of the system frame number SFN of the first wireless frame are not zero, the rest positions except the lower three bits in the information position carried by the first PBCH in the first wireless frame are set to be zero to obtain the first PBCH carried information ynN is used for representing the value of the SFN of the first PBCH;
according to ynDetermining a difference between the information carried by the first PBCH and the information carried by the second PBCH in the second radio frame to be H (G (F (y))n) ); wherein H () is used to characterize as ynFunction of scrambling, G () being for characterizing as ynFunction for increasing cyclic redundancy, F () being for characterizing as ynA function of the encoding; wherein the second radio frame is a frame received before the first radio frame within a Transmission Time Interval (TTI), and the lower three bits of the SFN of the second radio frame are zero;
determining a first log-likelihood ratio (LLR) value for the first wireless frame based on the difference;
combining the first LLR value with a second LLR value of the second wireless frame to obtain a combined first combined LLR value;
and demodulating the first PBCH according to the first combined LLR value.
2. The method of claim 1, wherein if the demodulation result of the first PBCH is wrong, the method further comprises:
receiving a third wireless frame sent by the network equipment;
determining a difference between information carried by a third PBCH in the third radio frame and information carried by the second PBCH if the lower three bits of the SFN of the third radio frame are not zero;
determining a third LLR value of the third radio frame according to the difference;
combining the third LLR value with the first combined LLR value to obtain a combined second combined LLR value;
and demodulating the third PBCH according to the second combined LLR value until the last radio frame received in the TTI.
3. The method of claim 1, wherein determining the first LLR value for the first wireless frame from the difference comprises:
descrambling corresponding to the second scrambling is carried out on the first PBCH, and the LLR value and the H (G (F (y)) obtained after speed de-matching are carried outn) ) to determine a first LLR value for the first wireless frame.
4. The method of claim 3,
the first LLR ═ LLR (1-2 × (G (F (y)) H (G)) and (G) (G (y)) and (G) (G) and (G) (G) and (c) and (b) and (c) and (b) and (c) respectively) and (c) respectively)n))))*(1-2*H(G(F(y0))))；
Wherein, y0And the PBCH carried information when the value for representing the SFN is zero.
5. A terminal device, comprising:
a memory to store instructions;
a processor for reading the instructions in the memory, performing the following processes:
controlling a receiver to receive a first wireless frame sent by network equipment;
if the lower three bits of the system frame number SFN of the first wireless frame are not zero, the rest positions except the lower three bits in the information position carried by the first PBCH in the first wireless frame are set to be zero to obtain the first PBCH carried information ynN is used for representing the value of the SFN of the first PBCH;
according to ynDetermining a difference between the information carried by the first PBCH and the information carried by the second PBCH in the second radio frame to be H (G (F (y))n) ); wherein H () is used to characterize as ynFunction of scrambling, G () being for characterizing as ynFunction for increasing cyclic redundancy, F () being for characterizing as ynA function of the encoding; wherein the second radio frame is a frame received before the first radio frame within a Transmission Time Interval (TTI), and the lower three bits of the SFN of the second radio frame are zero;
determining a first log-likelihood ratio (LLR) value for the first wireless frame based on the difference;
combining the first LLR value with a second LLR value of the second wireless frame to obtain a combined first combined LLR value;
and demodulating the first PBCH according to the first combined LLR value.
6. The apparatus of claim 5, wherein when the demodulation result for the first PBCH is in error, the processor is further configured to:
controlling the receiver to receive a third wireless frame sent by the network equipment;
determining a difference between information carried by a third PBCH in the third radio frame and information carried by the second PBCH if the lower three bits of the SFN of the third radio frame are not zero; determining a third LLR value of the third wireless frame according to the difference;
combining the third LLR value with the first combined LLR value to obtain a combined second combined LLR value;
and demodulating the third PBCH according to the second combined LLR value until the last radio frame received in the TTI.
7. The device of claim 5, wherein when the processor determines the first LLR value for the first wireless frame based on the difference, it is specifically configured to:
descrambling corresponding to the second scrambling is carried out on the first PBCH, and the LLR value and the H (G (F (y)) obtained after speed de-matching are carried outn) )) of the first wireless frame is determinedThe LLR value.
8. The apparatus of claim 7,
the first LLR ═ LLR (1-2 × (G (F (y)) H (G)) and (G) (G (y)) and (G) (G) and (G) (G) and (c) and (b) and (c) and (b) and (c) respectively) and (c) respectively)n))))*(1-2*H(G(F(y0))))；
Wherein, y0And the PBCH carried information when the value for representing the SFN is zero.
9. A terminal device, comprising:
a receiving module, configured to receive a first wireless frame sent by a network device;
a determining module, configured to, when the lower three bits of the system frame number SFN of the first wireless frame are not zero, zero the remaining positions except the lower three bits in the information bits carried by the first PBCH in the first wireless frame, so as to obtain the first PBCH carrying information ynN is used for representing the value of the SFN of the first PBCH;
according to ynDetermining a difference between the information carried by the first PBCH and the information carried by the second PBCH in the second radio frame to be H (G (F (y))n) ); wherein H () is used to characterize as ynFunction of scrambling, G () being for characterizing as ynFunction for increasing cyclic redundancy, F () being for characterizing as ynA function of the encoding; wherein the second radio frame is a frame received before the first radio frame within a Transmission Time Interval (TTI), and the lower three bits of the SFN of the second radio frame are zero;
determining a first log-likelihood ratio (LLR) value for the first wireless frame based on the difference;
combining the first LLR value with a second LLR value of the second wireless frame to obtain a combined first combined LLR value;
and demodulating the first PBCH according to the first combined LLR value.
10. A computer storage medium having stored therein instructions that, when executed on a computer, cause the computer to perform the method of any one of claims 1-4.
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