CN108882388B - Random access method and base station - Google Patents
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Abstract
The embodiment of the invention provides a random access method and a base station, which are used for realizing the random access of a terminal to a network. The method comprises the following steps: a base station receives a random access lead code sent by a terminal; the base station obtains parameters of a correlation peak in each zero correlation window in at least one zero correlation window according to the received random access lead code and a pre-stored random access lead code set, wherein the random access lead code contained in the random access lead code set corresponds to the zero correlation window one by one, and the parameters of the correlation peak comprise the power and/or the time lead of the random access lead code; and when the parameters of the correlation peak meeting the preset condition exist in the parameters of the correlation peak in each zero correlation window in at least one zero correlation window, the base station sends a random access response message comprising the parameters of the correlation peak meeting the preset condition to the terminal.
Description
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a random access method and a base station.
Background
Random access is a necessary process for establishing a radio link between a terminal and a network, and the terminal can communicate with a base station only after random access is completed.
In the process of Random Access, a terminal determines the time for sending a Random Access Preamble (Preamble) to a base station according to configuration parameters issued by the base station, and sends the Random Access Preamble to the base station at the time, wherein the Random Access Preamble is obtained by the sequence displacement of the Random Access Preamble (Zadoff-Chu). And after receiving the random access lead code sent by the terminal, the base station obtains a correlation peak falling in a zero correlation window according to the random access lead code and each Zadoff-Chu sequence in a random access lead code set saved in advance. Since the zero correlation window corresponds to the identifier (Preamble ID) of the random access Preamble one to one, the base station can determine the identifier of the random access Preamble corresponding to the random access Preamble sent by the terminal by determining the zero correlation window where the correlation peak is located. The base station transmits the parameters of the correlation peak and the identification of the random access preamble to the terminal through a random access response message.
In the existing technical solution of random access, a terminal sends a random access preamble to a base station in advance or in a delayed manner, which may cause a correlation peak obtained by the base station to fall within an incorrect zero correlation window, or may cause correlation peaks obtained by the base station to fall within a plurality of zero correlation windows due to energy leakage of the random access preamble received by the base station, both of which may cause the base station to determine an identifier of the incorrect random access preamble and parameters of the incorrect correlation peaks, so that the terminal cannot perform uplink synchronization according to a random access response sent by the base station, and at this time, the random access response sent by the base station is an invalid random access response, which further causes a long time delay of random access and a high random access failure rate. The base station may wrongly judge the interference noise as the random access preamble, and send a random access response according to the wrongly judged random access preamble, and the random access response sent by the base station is an invalid random access response, so that the resource of the base station is wasted, and the running speed of the base station is slowed down.
In summary, the existing random access technical solutions have the problems of long random access time, high random access failure rate, waste of base station resources, slow operation speed, and the like, and thus a technical solution for implementing a terminal random access network is urgently needed to be designed.
Disclosure of Invention
The embodiment of the invention provides a random access method and a base station, which are used for realizing the random access of a terminal to a network.
In a first aspect, an embodiment of the present invention provides a random access method, including:
a base station receives a random access lead code sent by a terminal;
the base station obtains parameters of a correlation peak in each zero correlation window in at least one zero correlation window according to the received random access lead code and a pre-stored random access lead code set, wherein the random access lead code contained in the random access lead code set corresponds to the zero correlation window one by one, and the parameters of the correlation peak comprise the power and/or the time lead of the random access lead code;
and when the parameters of the correlation peak meeting the preset condition exist in the parameters of the correlation peak in each zero correlation window in at least one zero correlation window, the base station sends a random access response message comprising the parameters of the correlation peak meeting the preset condition to the terminal.
In one possible design, further comprising:
when there is no parameter of a correlation peak satisfying a preset condition among the parameters of correlation peaks falling within each of at least one zero correlation window, the base station determines that the terminal is not allowed to perform random access based on the received random access preamble.
In one possible design, the preset conditions are specifically:
the power of the random access preamble code is larger than a first threshold value; and/or the timing advance is less than a second threshold.
In one possible design, the obtaining, by the base station, the parameter of the correlation peak falling within each zero correlation window of the at least one zero correlation window according to the received random access preamble and a pre-stored random access preamble set includes:
the base station determines a correlation peak in each zero correlation window in at least one zero correlation window according to the received random access lead code and the random access lead code set;
for a correlation peak falling in each zero correlation window in at least one zero correlation window, the base station determines the power and/or the time advance of a random access preamble code corresponding to the correlation peak, the power of the random access preamble code is determined according to the peak value of the correlation peak, and the time advance is the time between the time of the zero correlation window in which the correlation peak falls and the starting time of the zero correlation window.
In one possible design, before the base station receives the random access preamble sent by the terminal, the method further includes:
when a plurality of terminals which send random access lead codes to the base station in advance are provided, the base station indicates a random access lead code to each terminal in the plurality of terminals respectively, and the random access lead code indicated to each terminal in the plurality of terminals is a discontinuous random access lead code in a random access lead code set.
In a second aspect, an embodiment of the present invention provides a base station, including:
the receiving and sending unit is used for receiving a random access lead code sent by the terminal;
the processing unit is used for obtaining parameters of a correlation peak in each zero correlation window in at least one zero correlation window according to the random access lead code received by the transceiving unit and a pre-stored random access lead code set, the random access lead code contained in the random access lead code set corresponds to the zero correlation window one by one, and the parameters of the correlation peak comprise the power and/or the time lead of the random access lead code; when the parameters of the correlation peak in each zero correlation window in at least one zero correlation window have the parameters of the correlation peak meeting the preset condition, controlling the transceiver unit to send a random access response message comprising the parameters of the correlation peak meeting the preset condition to the terminal;
and the transceiving unit is further used for sending a random access response message including parameters of the correlation peak meeting the preset conditions to the terminal under the control of the processing unit.
In one possible design, the processing unit is further configured to:
and when the parameters of the correlation peak meeting the preset condition do not exist in the parameters of the correlation peak in each zero correlation window in at least one zero correlation window, determining that the terminal is not allowed to carry out random access based on the random access preamble code received by the transceiving unit.
In one possible design, the preset conditions are specifically:
the power of the random access preamble code is larger than a first threshold value, and/or the time advance is smaller than a second threshold value.
In a possible design, the processing unit obtains, according to the received random access preamble and a set of random access preambles stored in advance, a parameter of a correlation peak falling within each zero correlation window of the at least one zero correlation window, and is specifically configured to:
determining a correlation peak falling in each zero correlation window in at least one zero correlation window according to the received random access lead code and the random access lead code set;
and aiming at a correlation peak falling in each zero correlation window in at least one zero correlation window, determining the power and/or the time advance of a random access preamble code corresponding to the correlation peak, wherein the power of the random access preamble code is determined according to the peak value of the correlation peak, and the time advance is the time between the time of the zero correlation window in which the correlation peak falls and the starting time of the zero correlation window.
In one possible design, the processing unit is further configured to:
before the transceiver unit receives the random access lead codes sent by the terminals, when the number of the terminals which send the random access lead codes to the base station in advance is multiple, the transceiver unit respectively indicates one random access lead code to each terminal in the multiple terminals, and one random access lead code indicated to each terminal is a random access lead code which is discontinuous with each other in a random access lead code set.
In the technical scheme provided by the embodiment of the invention, a base station receives a random access lead code sent by a terminal, the base station obtains parameters of a related peak in each zero related window in at least one zero related window according to the received random access lead code and a pre-stored random access lead code set, and when the parameters of the related peak in each zero related window in at least one zero related window have the parameters of the related peak meeting a preset condition, the base station sends a random access response message comprising the parameters of the related peak meeting the preset condition to the terminal. The technical scheme provided by the embodiment of the invention realizes that the base station sends the random access response to the terminal after the parameters of the correlation peak in each zero correlation window in at least one zero correlation window meet the preset conditions, reduces the influence of factors such as signal leakage, inaccurate terminal timing, interference noise and the like on the random access process, effectively avoids the base station sending invalid random access response, is beneficial to shortening the random access time delay, is beneficial to reducing the random access failure rate, is beneficial to reducing the base station resource waste and is beneficial to improving the problem of slow running speed of the base station.
Drawings
Fig. 1 is a schematic structural diagram of a zero correlation window when a random access preamble is sent in advance in the prior art;
fig. 2 is a schematic structural diagram of a zero correlation window when a signal leakage occurs in a random access preamble in the prior art;
fig. 3 is a flowchart illustrating a random access method according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a process of random access in a cell handover scenario according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a zero correlation window according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a base station according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of another base station according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention provides a random access method and a base station, which are used for realizing the random access of a terminal to a network. In the existing random access technical scheme, due to reasons such as inaccurate timing of a terminal, the terminal may send a random access preamble to a base station in advance or in a delayed manner, so that a correlation peak obtained by the base station according to the random access preamble falls within an incorrect zero correlation window, which may be referred to as a forward window. As shown in fig. 1, the random access preamble with the identifier 2 sent by the terminal falls within the zero correlation window with the identifier 3 of the random access preamble, and the base station will recognize the received identifier 3 of the random access preamble sent by the terminal. Due to the phenomenon of energy leakage of signals, when the random access preamble code received by the base station leaks energy, the base station may obtain a plurality of correlation peaks, and the correlation peaks may fall within a plurality of correlation windows, so that the random access preamble code determined by the base station may be an incorrect random access preamble code. As shown in fig. 2, since the random access preamble identified by 2 of the random access preamble has energy leakage, a correlation peak obtained by the base station according to the random access preamble falls within a zero correlation window identified by 2 of the random access preamble and a zero correlation window identified by 3 of the random access preamble, and meanwhile, another terminal sends the random access preamble identified by 3 of the random access preamble to the base station, so that the base station obtains two correlation peaks in the zero correlation window identified by 3 of the random access preamble, and usually, when a plurality of correlation peaks exist in one zero correlation window, the correlation peak parameter is determined according to the correlation peak with the highest peak value among the plurality of correlation peaks, so that the base station determines the correlation peak parameter according to the correlation peak corresponding to the signal leaked from the random access preamble identified by 2 of the random access preamble, so that the correlation peak parameter received by the terminal sending the random access preamble identified by 3 of the random access preamble is an error The parameter of the correlation peak of (1) causes the random access failure of the terminal. Furthermore, the base station may misinterpret the interference noise as a random access preamble, so that the base station transmits an invalid random access response without the terminal transmitting the random access preamble to the base station.
In the technical scheme of the embodiment of the invention, before the base station sends the random access response to the terminal, the base station needs to obtain the parameters of the related peak in each zero related window in at least one zero related window according to the random access lead code sent by the terminal, and when the base station determines that the parameters of the related peak meet the preset conditions, the base station sends the parameters of the related peak to the terminal through the random access response, so that the influence of factors such as signal leakage, inaccurate timing of the terminal, interference noise and the like on the random access process is reduced, the base station is prevented from sending invalid random access response, the random access time delay is favorably shortened, the random access failure rate is favorably reduced, the resource waste of the base station is favorably reduced, and the running speed of the base station is favorably accelerated. The method and the device are based on the same inventive concept, and because the principles of solving the problems of the method and the device are similar, the implementation of the device and the method can be mutually referred, and repeated parts are not repeated.
The embodiment of the invention is suitable for a scene that the base station sends the random access response message to the terminal in the random access process, in particular to a scene that the base station sends the random access response message to the terminal in the non-competitive random access process. For example, in a cell handover process, a target cell sends a random access response message to a terminal, when downlink data sent by a base station to the terminal reaches the terminal and an air interface of the terminal is in an up-down out-of-step state, the base station sends the random access response message to the terminal, and in an auxiliary positioning process, the base station sends the random access response message to the terminal.
The network equipment related to the embodiment of the invention comprises a base station, and the base station comprises a plurality of cells. A base station may also be referred to as an access point, or as a device in an access network that communicates over the air-interface, through one or more sectors, with wireless terminals, or by other names, depending on the particular application. The base station may be configured to interconvert received air frames with Internet Protocol (IP) packets as a router between the wireless terminal and the rest of the access network, which may include an Internet Protocol (IP) communication network. The base station may also coordinate management of attributes for the air interface. For example, the base Station may be a network device (BTS) in Global System for Mobile Communications (GSM) or Code Division Multiple Access (CDMA), a network device (NodeB) in Wideband Code Division Multiple Access (WCDMA), or an evolved Node B (eNB) in LTE, which is not limited in the embodiment of the present invention.
A terminal according to embodiments of the present invention may refer to a device that provides voice and/or data connectivity to a user, a handheld device having wireless connectivity, or other processing device connected to a wireless modem. A wireless terminal may communicate with one or more core networks via a Radio Access Network (RAN), and wireless user equipment may be mobile terminals such as mobile telephones (or "cellular" telephones) and computers with mobile terminals, such as portable, pocket, hand-held, computer-included, or vehicle-mounted mobile devices, that exchange language and/or data with the RAN. Examples of such devices include Personal Communication Service (PCS) phones, cordless phones, Session Initiation Protocol (SIP) phones, Wireless Local Loop (WLL) stations, and Personal Digital Assistants (PDAs). A wireless User Equipment may also be referred to as a system, a Subscriber Unit (Subscriber Unit), a Subscriber Station (Subscriber Station), a Mobile Station (Mobile), a Remote Station (Remote Station), an Access Point (Access Point), a Remote Terminal (Remote Terminal), an Access Terminal (Access Terminal), a User Terminal (User Terminal), a User Agent (User Agent), a User Equipment (User Device), or a User Equipment (User Equipment).
The random access related to the embodiment of the invention is a necessary process for establishing a wireless link between a terminal and a network, and the terminal communicates with a base station after completing the random access. The random access can be divided into contention random access initiated by the terminal and non-contention random access initiated by the base station.
The random access preamble code related to the embodiment of the invention is a numerical sequence generated by cyclic shift of a Zadoff-Chu sequence with zero correlation property. Since the autocorrelation and the cross-correlation of the random access preamble codes are good, a peak value does not appear in a result sequence obtained by performing correlation operation on two different random access preamble codes, and a peak value appears in a result sequence obtained by performing correlation operation on two same random access preamble codes, and the peak value is called a correlation peak. Usually, each cell of the base station stores a random access preamble sequence code set, the random access preamble sequence code set is composed of at least one Zadoff-Chu sequence and a random access preamble code corresponding to the Zadoff-Chu sequence, correlation peaks obtained by calculating each random access preamble code and the corresponding Zadoff-Chu sequence fall into a corresponding zero correlation window, and the zero correlation windows are in one-to-one correspondence with the identifiers of the random access preamble codes.
The correlation algorithm related to the embodiment of the present invention may be one or more of correlation algorithms in the prior art, and these correlation algorithms are classified into an autocorrelation algorithm and a cross-correlation algorithm, which are not limited in the implementation of the present invention.
The zero correlation window according to the embodiment of the present invention refers to the length of a portion having no correlation included in two sequences. The window length of zero correlation used in the random access procedure may be configured to the terminal by the base station.
The following detailed description of various embodiments of the invention refers to the accompanying drawings. It should be noted that the display sequence of the embodiment of the present invention only represents the sequence of the embodiment, and does not represent the merits of the technical solutions provided by the embodiments.
As shown in fig. 3, an embodiment of the present invention provides a random access method, where the method includes:
s301, the base station receives the random access preamble sent by the terminal.
The base station can pre-store a random access preamble sequence code set, the random access preamble sequence set is composed of at least one Zadoff-Chu sequence and a random access preamble code corresponding to the Zadoff-Chu sequence, a correlation peak obtained after correlation calculation is carried out on each random access preamble code and the corresponding Zadoff-Chu sequence is located in a uniquely corresponding zero correlation window, random access preamble codes contained in the random access preamble code set correspond to the zero correlation windows one by one, and the zero correlation windows correspond to the identifiers of the random access preamble codes one by one.
In S301, the base station receives a random access preamble sent by the terminal, where the random access preamble may be determined by the terminal according to an identifier of the random access preamble sent by the base station, or may be a random access preamble randomly selected by the terminal from at least one random access preamble that is pre-stored and available for contention for random access.
Preferably, before the base station receives the random access preamble transmitted by the terminal, when there are a plurality of terminals that have transmitted the random access preamble to the base station in advance, the base station may indicate one random access preamble to each of the plurality of terminals, respectively. The base station may send a random access preamble to each of the plurality of terminals, or may send an identifier of a random access preamble to each of the plurality of terminals. The random access preamble indicated to each of the plurality of terminals is a random access preamble that is discontinuous with each other in the random access preamble set, and intervals between the discontinuous random access preambles may be the same or different, which is not limited in the embodiment of the present invention. Since the non-contention random access is initiated by the base station and the contention random access is initiated by the terminals, the method in which the base station indicates a random access preamble to each of the plurality of terminals is preferentially applied to the scenario of the non-contention random access.
Therefore, when a plurality of terminals which send random access lead codes to the base station in advance are provided, the base station can indicate the random access lead codes through the terminals, so that when the plurality of terminals send the random access lead codes to the same base station, a plurality of correlation peaks obtained by the base station respectively fall in different zero correlation windows with certain intervals, the phenomenon that a plurality of correlation peaks are obtained in one zero correlation window due to energy leakage of the random access lead codes is avoided, the random access time delay is favorably shortened, and the random access failure rate is favorably reduced.
Taking a random access process in a cell handover scenario as an example, as shown in fig. 4, a source cell sends a handover request message to a destination cell, after receiving the handover request message, the destination cell sends a handover request acknowledgement message to the source cell, where the handover request acknowledgement message carries an identifier m of a random access code corresponding to a random access code allocated to a terminal 1 by a base station to which the destination cell belongs, and the identifier of the random access code is used for the terminal 1 to randomly access a network by using the random access code corresponding to the identifier of the random access code. After receiving the handover request acknowledgement message sent by the target cell, the source cell sends a Radio Resource Control (RRC) connection reconfiguration message to the terminal 1, where the RRC connection reconfiguration message carries an identifier m of a random access code allocated to the terminal 1 by a base station to which the target cell belongs. After receiving the RRC connection reconfiguration message, the terminal 1 sends a random access code identified as m to the target cell. Similarly, the base station to which the destination cell belongs sends the identifier m +2 of the random access code corresponding to the random access code allocated to the terminal 2, and finally, after receiving the RRC connection reconfiguration message sent by the source cell, the terminal 2 sends the random access code with the identifier m +2 of the random access code to the destination cell.
S302, the base station obtains parameters of a correlation peak in each zero correlation window in at least one zero correlation window according to the received random access lead code and a pre-stored random access lead code set, wherein the random access lead code contained in the random access lead code set corresponds to the zero correlation window one by one.
The parameters of the correlation peak may include power and/or timing advance of the random access preamble. The power of the random access preamble is determined according to the peak value of the correlation peak, and the power of the random access preamble is used for the terminal to adjust the power of the terminal for sending the uplink data. The time advance is used for uplink synchronization between the terminal and the base station, and the time advance is the time between the time of a zero correlation window where the correlation peak falls and the starting time of the zero correlation window. It can also be understood that the distance between the position of the zero correlation window where the correlation peak falls and the start position of the zero correlation window is proportional to the time advance. As shown in fig. 5, the timing advance is the time between the time when the correlation peak falls within the zero correlation window of random access code identification 2 and the starting time of the zero correlation window of random access code identification 2. The random access preamble set is composed of at least one Zadoff-Chu sequence and its corresponding random access preamble.
In S302, the base station may perform correlation calculation on the received random access preamble and each Zadoff-Chu sequence in the pre-stored random access preamble set, and since the random access preambles included in the random access preamble set correspond to the zero correlation windows one to one, a correlation peak falling in each zero correlation window of at least one zero correlation window may be obtained, and then a parameter of the correlation peak is obtained according to the correlation peak. For the correlation peak falling in each zero correlation window in at least one zero correlation window, the base station respectively determines the parameters of the correlation peak corresponding to the correlation peak, that is, the base station respectively determines the power and/or the time advance of the random access preamble code corresponding to the correlation peak, so that the base station can determine the correlation peak corresponding to the random access preamble code according to the parameters of the correlation peak and determine whether the random access preamble code is sent to the base station at the time determined according to the configuration parameters issued by the base station.
It should be noted that, in addition to the parameter for determining the correlation peak by using the above method, other methods in the prior art may also be used to determine the parameter of the correlation peak, and the embodiment of the present invention is not limited thereto
And S303, when the parameters of the correlation peak meeting the preset condition exist in the parameters of the correlation peak in each zero correlation window in at least one zero correlation window, the base station sends a random access response message comprising the parameters of the correlation peak meeting the preset condition to the terminal.
The preset condition is that the power of the random access preamble code is larger than a first threshold value, and/or the time advance is smaller than a second threshold value. Namely: when the parameter of the correlation peak includes the power of the random access preamble, the preset condition may be that the power of the random access preamble is greater than a first threshold; when the parameter of the correlation peak includes the time advance, the preset condition may be that the time advance is smaller than a second threshold; when the parameters of the correlation peak include the power of the random access preamble and the time advance, the preset condition may be that the power of the random access preamble is greater than a first threshold and the time advance is less than a second threshold.
Usually, the base station can only obtain one correlation peak falling in a zero correlation window according to a received random access preamble, but when energy leakage occurs to a random access preamble received by the base station, the base station may obtain a plurality of correlation peaks falling in a zero correlation window after performing correlation calculation, or a plurality of correlation peaks falling in a plurality of zero correlation windows, wherein only one correlation peak is obtained according to the random access preamble and a pre-stored random access preamble set, and the remaining correlation peaks are obtained according to a leaked signal of the random access preamble and the pre-stored random access preamble set. When the parameter of the correlation peak included in the random access response message sent by the base station to the terminal is the parameter of the correlation peak obtained according to the leaked signal of the random access preamble, the random access failure may be caused because there is a large deviation between the parameter of the correlation peak obtained according to the leaked signal of the random access preamble and the parameter of the correlation peak obtained according to the random access preamble. In addition, based on the similar description above, random access failure may also be caused by reasons such as inaccurate timing of the base station, incorrect interpretation of interference noise as the random access preamble, and the like, which is not described herein again. Based on the reasons, the base station can reduce the influence of factors such as signal leakage, inaccurate terminal timing and misjudgment of interference noise as the random access lead code on the random access process by selecting the parameters of the correlation peak meeting the preset conditions, and the success rate of the random access is improved. When the power of the random access preamble of the correlation peak is greater than the first threshold, the correlation peak is obtained from the random access preamble transmitted by the terminal, and is not obtained from the leaked signal or interference noise of the random access preamble. When the time advance of the correlation peak is smaller than the second threshold, the correlation peak is obtained according to the random access lead code sent by the terminal to the base station at the time determined by the configuration parameters issued by the base station, but not according to the random access lead code sent by the terminal in advance or in a delayed manner.
Based on the above principle, in S303, when there is a parameter of a correlation peak that satisfies a preset condition in parameters of correlation peaks in each zero correlation window that falls in at least one zero correlation window, the base station may send a random access response message including the parameter of the correlation peak that satisfies the preset condition to the terminal, so that the terminal may adjust its configuration according to the parameter of the correlation peak and complete random access, thereby avoiding the base station sending an invalid random access response, contributing to shortening a random access delay, contributing to reducing a random access failure rate, contributing to reducing base station resource waste, and contributing to accelerating an operation speed of the base station.
Preferably, when there is no parameter of a correlation peak satisfying a preset condition among the parameters of correlation peaks falling within each of the at least one zero correlation window, the base station determines that the terminal is not allowed to perform random access based on the received random access preamble. Therefore, the base station is prevented from sending invalid random access response to the terminal, the resource waste of the base station is reduced, and the operation speed of the base station is accelerated.
In the embodiment of the present invention, the first threshold and the second threshold may be set by configuring a parameter of the base station. When configuring the first threshold, the target received power of the random access preamble sent by the receiving terminal configured by the base station may be referred to, and the first threshold is set to a value less than or equal to the target received power, so as to meet the requirements in practical applications. It should be noted that, in addition to the above method for determining the first threshold, the first threshold may also be determined by other methods in the prior art, which is not limited in the embodiment of the present invention.
In the embodiment of the present invention, when configuring the second threshold, one of the following two manners may be adopted:
the first method is as follows: m calculated by the following formula may be used to indicate that the timing advance may be close to the maximum value in the case of forward window, and the setting of the second threshold of the base station is performed with reference to the calculated M:
M＝(Ncs—1)*Nseq/(Nzc*m)
wherein N isseqFor the length of the random access preamble, NzcFor a sequence length, N, of a Zadoff-Chu sequence included in a set of random access preamble codes corresponding to a zero correlation windowcsM is a non-zero integer and is the length of the zero correlation window in which the correlation peak is located.
The second method comprises the following steps: according to the cell radius of the cell belonging to the base station, calculating the time advance corresponding to the signal sent by the terminal at the edge of the cell by the following formula, and setting the second threshold to be greater than or equal to the time advance:
timing advance (r × n)/(c × ts × k)
Where r is the cell radius of the cell belonging to the base station, c is the speed of light, ts is the sampling interval, n and k are both non-zero integers, for example, n may be 2, and k may be 16.
It should be noted that, in addition to determining the second threshold value in the above manner, the second threshold value may also be determined by using other methods in the prior art, which is not limited in the embodiment of the present invention.
In the random access method provided by the embodiment of the invention, a base station receives a random access lead code sent by a terminal, the base station obtains parameters of a correlation peak in each zero correlation window in at least one zero correlation window according to the received random access lead code and a random access lead code set stored in advance, and when the parameters of the correlation peak in each zero correlation window in at least one zero correlation window have the parameters of the correlation peak meeting a preset condition, the base station sends a random access response message including the parameters of the correlation peak meeting the preset condition to the terminal. According to the random access method provided by the embodiment of the invention, the base station sends the random access response to the terminal after the parameters of the correlation peak in each zero correlation window in at least one zero correlation window meet the preset conditions, so that the influence of factors such as signal leakage, inaccurate terminal timing, interference noise and the like on the random access process is reduced, the base station is effectively prevented from sending invalid random access response, the random access time delay is favorably shortened, the random access failure rate is favorably reduced, the waste of base station resources is favorably reduced, and the problem of slow running speed of the base station is favorably solved.
With reference to the foregoing embodiment, an embodiment of the present invention provides a base station, where the base station may use the method provided in the embodiment corresponding to fig. 3, and as shown in fig. 6, the base station includes: a transceiver 601 and a processing unit 602.
A transceiver 601, configured to receive a random access preamble sent by a terminal;
a processing unit 602, configured to obtain, according to the random access preamble received by the transceiver 601 and a pre-stored random access preamble set, a parameter of a correlation peak in each zero correlation window in at least one zero correlation window, where the random access preamble included in the random access preamble set corresponds to the zero correlation window one to one, and the parameter of the correlation peak includes power and/or a time advance of the random access preamble; when the parameters of the correlation peak in each zero correlation window in at least one zero correlation window have the parameters of the correlation peak meeting the preset condition, controlling the transceiver unit to send a random access response message comprising the parameters of the correlation peak meeting the preset condition to the terminal;
the transceiver 601 is further configured to send a random access response message including a parameter of a correlation peak satisfying a preset condition to the terminal under the control of the processing unit.
Optionally, the processing unit 602 is further configured to:
and when the parameters of the correlation peak meeting the preset condition do not exist in the parameters of the correlation peak in each zero correlation window in at least one zero correlation window, determining that the terminal is not allowed to carry out random access based on the random access preamble code received by the transceiving unit.
Optionally, the preset condition is specifically that the power of the random access preamble is greater than a first threshold, and/or the time advance is smaller than a second threshold.
Optionally, the processing unit 602 obtains, according to the received random access preamble and a pre-stored random access preamble set, a parameter of a correlation peak in each zero correlation window in at least one zero correlation window, and is specifically configured to:
determining a correlation peak falling in each zero correlation window in at least one zero correlation window according to the received random access lead code and the random access lead code set;
and aiming at a correlation peak falling in each zero correlation window in at least one zero correlation window, determining the power and/or the time advance of a random access preamble code corresponding to the correlation peak, wherein the power of the random access preamble code is determined according to the peak value of the correlation peak, and the time advance is the time between the time of the zero correlation window in which the correlation peak falls and the starting time of the zero correlation window.
Optionally, the processing unit 602 is further configured to:
before the transceiver 601 receives the random access preamble sent by the terminal, when there are a plurality of terminals that are intended to send the random access preamble to the base station, the transceiver 601 respectively indicates one random access preamble to each of the plurality of terminals, and the one random access preamble indicated to each terminal is a random access preamble that is discontinuous with each other in the random access preamble set.
It should be noted that the division of the unit in the embodiment of the present invention is schematic, and is only a logic function division, and there may be another division manner in actual implementation. In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be substantially implemented or contributed by the prior art, or all or part of the technical solution may be embodied in a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, a network device, or the like) or a processor (processor) to execute all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a Read-only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
Based on the above embodiments, the embodiment of the present invention further provides a base station, where the base station may adopt the method provided by the embodiment corresponding to fig. 3, and may be the same base station as the base station shown in fig. 6. Referring to fig. 7, the base station includes: a processor 701, a transceiver 702, a bus 703, and a memory 704, wherein:
a processor 701, configured to read the program in the memory 704, and execute the following processes:
a processor 701, configured to control the transceiver 702 to receive a random access preamble sent by a terminal;
the processor 701 is further configured to obtain, according to the random access preamble received by the transceiver 702 and a pre-stored random access preamble set, a parameter of a correlation peak in each zero correlation window in at least one zero correlation window, where the random access preamble included in the random access preamble set corresponds to the zero correlation window one to one, and the parameter of the correlation peak includes power and/or a time advance of the random access preamble;
the processor 701 is further configured to control the transceiver 702 to transmit a random access response message including parameters of a correlation peak satisfying a preset condition to the terminal when there are parameters of a correlation peak satisfying the preset condition among the parameters of correlation peaks falling within each of the at least one zero correlation window.
Optionally, the processor 701 is further configured to:
when there is no parameter of a correlation peak satisfying a preset condition among the parameters of correlation peaks falling within each of the at least one zero correlation window, it is determined that the terminal is not allowed to perform random access based on the random access preamble received by the transceiver 702.
Optionally, the preset condition is specifically that the power of the random access preamble is greater than a first threshold, and/or the time advance is smaller than a second threshold.
Optionally, when the processor 701 obtains the parameter of the correlation peak in each zero correlation window of the at least one zero correlation window, it is specifically configured to:
determining a correlation peak falling in each zero correlation window in at least one zero correlation window according to the received random access lead code and the random access lead code set;
and aiming at a correlation peak falling in each zero correlation window in at least one zero correlation window, determining the power and/or the time advance of a random access preamble code corresponding to the correlation peak, wherein the power of the random access preamble code is determined according to the peak value of the correlation peak, and the time advance is the time between the time of the zero correlation window in which the correlation peak falls and the starting time of the zero correlation window.
Optionally, the processor 701 is further configured to: before the control transceiver 702 receives the random access preamble sent by the terminal, when there are a plurality of terminals that are to send the random access preamble to the base station in advance, the control transceiver 702 respectively indicates one random access preamble to each of the plurality of terminals, and one random access preamble indicated to each terminal is a random access preamble that is discontinuous with each other in the random access preamble set.
A transceiver 702 for receiving and transmitting data under the control of the processor 701.
The processor 701, the transceiver 702, and the memory 704 are connected to each other by a bus 703; the bus 703 may be a Peripheral Component Interconnect (PCI) bus, an Extended Industry Standard Architecture (EISA) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc.
Wherein in fig. 7 the bus architecture may include any number of interconnected buses and bridges, with one or more processors, represented by processor 701, and various circuits of memory, represented by memory 704, being linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface. The transceiver 702 may be a number of elements, including a transmitter and a transceiver, providing a means for communicating with various other apparatus over a transmission medium. The processor 701 is responsible for managing the bus architecture and general processing, and the memory 704 may store data used by the processor 701 in performing operations.
Alternatively, the processor 701 may be a central processing unit, an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), or a Complex Programmable Logic Device (CPLD).
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention 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 invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. 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.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments of the present invention without departing from the spirit or scope of the embodiments of the invention. Thus, if such modifications and variations of the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to encompass such modifications and variations.
Claims (8)
1. A random access method, comprising:
a base station receives a random access lead code sent by a terminal;
the base station obtains parameters of a correlation peak in each zero correlation window in at least one zero correlation window according to the received random access lead code and a pre-stored random access lead code set, wherein the random access lead code contained in the random access lead code set corresponds to the zero correlation window one by one, and the parameters of the correlation peak comprise the power and/or the time lead of the random access lead code;
when the parameters of the correlation peak meeting the preset condition exist in the parameters of the correlation peak in each zero correlation window in at least one zero correlation window, the base station sends a random access response message comprising the parameters of the correlation peak meeting the preset condition to the terminal;
before the base station receives the random access preamble sent by the terminal, the method further includes:
when a plurality of terminals which send random access lead codes to the base station in advance are provided, the base station indicates a random access lead code to each terminal in the plurality of terminals respectively, and the random access lead code indicated to each terminal in the plurality of terminals is a discontinuous random access lead code in the random access lead code set, so that a plurality of correlation peaks obtained after the base station receives the random access lead codes sent by the plurality of terminals respectively fall in different zero correlation windows.
2. The method of claim 1, further comprising:
when the parameters of the correlation peak meeting the preset condition do not exist in the parameters of the correlation peak in each zero correlation window in at least one zero correlation window, the base station determines that the terminal is not allowed to carry out random access based on the received random access preamble code.
3. The method according to any one of claims 1 or 2, wherein the preset conditions are in particular: the power of the random access preamble code is larger than a first threshold value, and/or the time advance is smaller than a second threshold value.
4. The method of claim 1, wherein the base station obtains parameters of correlation peaks falling within each zero correlation window of at least one zero correlation window according to the received random access preamble and a pre-stored set of random access preambles, comprising:
the base station determines a correlation peak falling in each zero correlation window in at least one zero correlation window according to the received random access lead code and the random access lead code set;
and aiming at the correlation peak falling in each zero correlation window in at least one zero correlation window, the base station determines the power and/or the time advance of the random access preamble code corresponding to the correlation peak, wherein the power of the random access preamble code is determined according to the peak value of the correlation peak, and the time advance is the time between the time of the zero correlation window in which the correlation peak falls and the starting time of the zero correlation window.
5. A base station, comprising:
the receiving and sending unit is used for receiving a random access lead code sent by the terminal;
a processing unit, configured to obtain, according to the random access preamble received by the transceiver unit and a pre-stored random access preamble set, a parameter of a correlation peak in each zero correlation window in at least one zero correlation window, where the random access preamble included in the random access preamble set corresponds to the zero correlation window one to one, and the parameter of the correlation peak includes power and/or a time advance of the random access preamble; when the parameters of the correlation peak meeting the preset condition exist in the parameters of the correlation peak in each zero correlation window in at least one zero correlation window, controlling the transceiver unit to send a random access response message comprising the parameters of the correlation peak meeting the preset condition to the terminal;
the transceiver unit is further configured to send a random access response message including the parameter of the correlation peak satisfying the preset condition to the terminal under the control of the processing unit;
the processing unit is further to:
before the transceiver unit receives random access lead codes sent by terminals, when a plurality of terminals which are to send the random access lead codes to the base station in advance are provided, the transceiver unit respectively indicates a random access lead code to each terminal in the plurality of terminals, and the random access lead code indicated to each terminal is a random access lead code which is not continuous with each other in the random access lead code set, so that a plurality of correlation peaks obtained after the base station receives the random access lead codes sent by the plurality of terminals respectively fall in different zero correlation windows.
6. The base station of claim 5, wherein the processing unit is further to:
when the parameters of the correlation peak which meets the preset condition do not exist in the parameters of the correlation peak in each zero correlation window in at least one zero correlation window, determining that the terminal is not allowed to carry out random access based on the random access preamble code received by the transceiver unit.
7. The base station of any of claims 5 or 6, wherein the predetermined condition is specifically:
the power of the random access preamble code is larger than a first threshold value, and/or the time advance is smaller than a second threshold value.
8. The base station of claim 5, wherein the processing unit, when obtaining the parameters of the correlation peak falling within each zero correlation window of the at least one zero correlation window, is specifically configured to:
determining a correlation peak falling in each zero correlation window in at least one zero correlation window according to the random access lead code received by the transceiver unit and the random access lead code set;
and aiming at the correlation peak falling in each zero correlation window in at least one zero correlation window, determining the power and/or the time lead of the random access preamble code corresponding to the correlation peak, wherein the power of the random access preamble code is determined according to the peak value of the correlation peak, and the time lead is the time between the time of the zero correlation window in which the correlation peak falls and the starting time of the zero correlation window.
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