CN106937400B - Random access method, base station and user equipment - Google Patents
Random access method, base station and user equipment Download PDFInfo
- Publication number
- CN106937400B CN106937400B CN201511019645.0A CN201511019645A CN106937400B CN 106937400 B CN106937400 B CN 106937400B CN 201511019645 A CN201511019645 A CN 201511019645A CN 106937400 B CN106937400 B CN 106937400B
- Authority
- CN
- China
- Prior art keywords
- base station
- interference
- random access
- uplink
- symbol
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000000034 method Methods 0.000 title claims abstract description 35
- 230000004044 response Effects 0.000 claims abstract description 25
- 125000004122 cyclic group Chemical group 0.000 claims description 8
- 230000002452 interceptive effect Effects 0.000 claims description 8
- 238000004891 communication Methods 0.000 abstract description 7
- 238000010586 diagram Methods 0.000 description 5
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 230000005540 biological transmission Effects 0.000 description 3
- 230000002045 lasting effect Effects 0.000 description 3
- 230000000977 initiatory effect Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 230000001413 cellular effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 238000002513 implantation Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 230000008447 perception Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access
- H04W74/002—Transmission of channel access control information
- H04W74/006—Transmission of channel access control information in the downlink, i.e. towards the terminal
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access
- H04W74/08—Non-scheduled access, e.g. ALOHA
- H04W74/0866—Non-scheduled access, e.g. ALOHA using a dedicated channel for access
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
The invention discloses a random access method, a base station and user equipment, wherein the method comprises the following steps: the base station judges whether the same frequency interference exists at present; if the same frequency interference exists, the base station sends a system message carrying an interference preamble sequence format to User Equipment (UE) under the base station, wherein the interference preamble sequence format is used for indicating that time domain resources occupied by a Physical Random Access Channel (PRACH) of the UE are from the ith symbol to the (i + n) th symbol of at least a first uplink subframe of each half frame in a wireless frame, and the base station receives a lead code which is sent by the UE and used for random access on the time domain resources indicated by the interference preamble format; and if the base station correctly demodulates the lead code, sending a random access response to the UE, so as to solve the problem that the UE access fails due to the existing PRACH lead sequence format when the same frequency interference is encountered, and reduce the UE access success rate of the whole communication system.
Description
Technical Field
The present invention relates to the field of communications, and in particular, to a random access method, a base station, and a user equipment.
Background
Modern mobile communication tends to provide a multimedia service with high-speed transmission more and more, in an LTE (Long term evolution) system, a PRACH (Physical Random Access Channel) is an uplink Random Access Channel, and after receiving a FPACH (Fast Physical Access Channel) response message, a UE (User Equipment) transmits an RRC (Radio Resource Control, Radio Resource Control protocol) message on the PRACH according to information indicated by a base station to establish an RRC connection.
In the 3GPP R8 (third generation partnership project) specification, when an LTE system configures an uplink PRACH channel, multiple Preamble formats are designed for LTE _ FDD and TD _ LTE to meet different cell coverage radius requirements. The Preamble format types 0, 1, 2, and 3(Preamble format 0, 1, 2, and 3) are common to LTE _ FDD and TD _ LTE, and for a special frame structure of TD _ LTE, a Preamble format type 4(Preamble format 4) is designed for hot spot coverage when the cell radius is small. However, when co-channel interference occurs, the conventional PRACH preamble sequence format may cause a base station to fail to detect and analyze a random code transmitted by the UE on the PRACH, which may eventually cause the UE to fail to successfully access the communication system, resulting in a decrease in UE access success rate of the entire communication system.
Therefore, when co-channel interference is encountered, the existing PRACH channel preamble sequence format causes UE access failure, and the UE access success rate of the entire communication system is reduced.
Disclosure of Invention
The embodiment of the invention provides a random access method, a base station and user equipment, which are used for solving the problem that the UE access fails due to the existing PRACH preamble sequence format when co-frequency interference occurs, and the UE access success rate of the whole communication system is reduced.
The method comprises a random access method, which comprises the following steps: the base station judges whether the same frequency interference exists at present; if the same frequency interference exists, the base station sends a system message carrying an interference leader sequence format to User Equipment (UE) under the base station, wherein the interference leader sequence format is used for indicating that time domain resources occupied by PRACH of the UE are from the ith symbol to the (i + n) th symbol of at least a first uplink subframe of each half frame in a wireless frame, the uplink interference level value of the ith symbol is less than a first threshold value, and n is a positive integer not greater than 14; the base station receives a lead code which is sent by the UE and used for random access on the time domain resource indicated by the interference lead format; and if the base station correctly demodulates the lead code, sending a random access response to the UE.
From the user equipment side, an embodiment of the present invention further provides a random access method, where the method includes: the method comprises the steps that UE receives a system message which is sent by a base station and carries an interference preamble format, wherein the interference preamble sequence format is used for indicating that a time domain resource occupied by a PRACH of the UE is from an ith symbol to an (i + n) th symbol of at least a first uplink subframe of each half frame in a wireless frame, the uplink interference level value of the ith symbol is smaller than a first threshold value, and n is a positive integer not larger than 14; and the UE sends a lead code for random access on the PRACH resource so that the base station sends a random access response to the UE corresponding to the lead code which is correctly demodulated according to the lead code of each UE.
Based on the same inventive concept, an embodiment of the present invention provides a base station, including: the judging unit is used for judging whether the same frequency interference exists at present; a system message sending unit, configured to send a system message carrying an interference preamble format to a UE under the base station if co-channel interference exists, where the interference preamble sequence format is used to indicate that a time domain resource occupied by a PRACH of the UE is an ith to (i + n) th symbol of at least a first uplink subframe of each half frame in a radio frame, where an uplink interference level value of the ith symbol is less than a first threshold, and n is a positive integer not greater than 14; a receiving unit, configured to receive a preamble sent by a UE for performing random access on a time domain resource indicated by the interference preamble format; and a random access response sending unit, configured to send a random access response to the UE if the preamble is correctly demodulated.
Further, an embodiment of the present invention provides a user equipment, where the user equipment includes: a receiving unit, configured to receive a system message carrying an interference preamble format sent by a base station, where the interference preamble sequence format is used to indicate that a time domain resource occupied by a PRACH of a UE is an ith symbol to an i + nth symbol of at least a first uplink subframe of each half frame in a radio frame, where an uplink interference level value of the ith symbol is less than a first threshold, and n is a positive integer no greater than 14; and the sending unit is used for sending the lead code used for random access on the PRACH resource so that the base station sends a random access response to the UE corresponding to the correctly demodulated lead code according to the lead code of each UE.
On one hand, a base station judges whether co-channel interference exists at present, if so, a system message carrying an interference leader sequence format is sent to User Equipment (UE) under the base station, wherein the interference leader sequence format in the system message is a leader sequence format agreed by the base station and a terminal in advance, and the leader sequence format is characterized in that time domain resources occupied by a Physical Random Access Channel (PRACH) are from the ith symbol to the (i + n) th symbol of at least a first uplink subframe of each half frame in a wireless frame, and the uplink interference level value of the ith symbol is smaller than a first threshold value; on the other hand, the UE sends a preamble on the PRACH agreed to the interference preamble sequence format, and the base station sends a random access response to the UE after receiving the preamble and completing correct demodulation. Therefore, when the UE uses the PRACH with the interfering preamble sequence format defined in the embodiment of the present invention to send the preamble for access, the access success rate of the UE can be improved under the same frequency interference condition, and the access performance of the whole system can be improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 provides a random access preamble sequence on a PRACH channel for the prior art;
fig. 2 illustrates the location of the time domain resource of the PRACH with a Preamble format type of 4 provided in the prior art;
fig. 3 illustrates the location of the time domain resource of the PRACH in the prior art when the Preamble format type is 0;
fig. 4 is a diagram illustrating an interference level value of a symbol occupied by a PRACH in a time domain resource under co-channel interference according to the prior art;
fig. 5 is a flowchart illustrating a method for interfering with a preamble sequence format at a base station according to an embodiment of the present invention;
fig. 6 is a diagram illustrating a time domain resource location of a PRACH corresponding to an interference preamble sequence format according to an embodiment of the present invention;
fig. 7 is a flowchart illustrating a method for providing an interference preamble sequence format corresponding to a ue side according to an embodiment of the present invention;
fig. 8 is a diagram illustrating a base station according to an embodiment of the present invention;
fig. 9 is a schematic diagram of a user equipment according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, 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.
Various aspects are described herein in connection with a UE and/or a base station. A UE, a device (device) that provides voice and/or data connectivity to a user, including a wireless UE or a wired UE. The wireless UE may be a handheld device with wireless connection capability, or other processing device connected to a wireless modem, a mobile UE that communicates with one or more core networks via a radio access network. For example, wireless UEs may be mobile telephones (or "cellular" telephones) and computers with mobile UEs. As another example, a wireless UE may also be a portable, pocket, hand-held, computer-included, or vehicle-mounted mobile device. As another example, a wireless UE may be part of a mobile station, an access point, or a User Equipment (UE).
It should be noted that the PRACH is used as a random access, and is a way for a user to perform initial connection, handover, connection re-establishment, and resume uplink synchronization. The UE achieves uplink access and synchronization with a communication system through the PRACH.
The UE uses a random access leader sequence on a PRACH channel for access, wherein the random access leader sequence is a ZC sequence, and the expression is as follows:
xu,v(n)＝xu((n+Cv)mod Nzc)………… … equation 1
Wherein, CvFor cyclic shift implantation, NzcIn order to be a cycle period of time,
0≤n≤Nzc1, u is the cyclic index of the root sequence.
Random access preamble sequence on PRACH channel, including length TcpHas a Cyclic Prefix (CP) and a length TSEQAs shown in fig. 1, the specific parameters of the existing preamble sequence format are shown in table l.
Table 1:
| preamble sequence format | Tcp | TSEQ |
| Format 0 | 3168Ts | 24576Ts |
| Format 1 | 21024TS | 24576TS |
| Format 2 | 6240Ts | 59152Ts |
| Format 3 | 21024Ts | 59152Ts |
| format 4 | 448Ts | 4096Ts |
Wherein, Preamble format 0: the time duration is 1ms, the sequence length is 800us, the method is suitable for small and medium cells, the radius of the maximum cell is 14.53km, and the format meets most scenes covered by a network; preamble format 1: lasting 2ms, the sequence length is 800us, the method is suitable for large cells, and the radius of the largest cell is 77.34 km; preamble format 2: lasting 2ms, the sequence length is 1600us, the method is suitable for medium-sized cells, and the radius of the maximum cell is 29.53 km; preamble format 3: lasting for 3ms, the sequence length is 1600us, the method is suitable for ultra-large cells, and the radius of the maximum cell is 100.16 km; the method is generally used for scenes needing ultra-long distance coverage, such as sea surfaces, islands and the like; preamble format 4: the TDD mode is specially used for a format with duration of 157.292 mu s (burst of 2 OFDM symbols), is suitable for small cells, has a cell radius of less than or equal to 1.4km, and is generally applied to short-distance coverage, especially to dense urban areas, indoor coverage or hotspot supplementary coverage and other scenes.
In summary, the maximum radius of the supported cells under various existing preamble formats is shown in table 2.
Table 2:
in the existing TD-LTE system, when a network plans the configuration ratio of uplink and downlink subframes, a proper configuration must be selected according to a switching period. The subframe configuration of one radio frame of the TD-LTE system supports the following 7 kinds of DL: the UL formulation is shown in Table 3:
as can be seen from table 3: mode 0: 1 wireless frame comprises 2 downlink subframes, 6 uplink subframes and 2 special subframes; mode 1: 1 wireless frame comprises 4 downlink subframes, 4 uplink subframes and 2 special subframes; mode 2: 1 wireless frame comprises 6 downlink subframes, 2 uplink subframes and 2 special subframes; mode 3: 1 wireless frame comprises 6 downlink subframes, 3 uplink subframes and 1 special subframe; mode 4: 1 wireless frame comprises 7 downlink subframes, 2 uplink subframes and 1 special subframe; mode 5: 1 wireless frame comprises 8 downlink subframes, 1 uplink subframe and 1 special subframe; mode 6: the 1 radio frame includes 3 downlink subframes, 5 uplink subframes and 2 special subframes.
The existing TD-LTE system usually adopts a Preamble format type of 4 or a Preamble format type of 0. When the preamble format is 4, the PRACH occupies a middle 1.08MHz bandwidth (72 subcarriers) in the frequency domain and 2 symbols of uppts in the time domain, as shown in fig. 2.
When the preamble format is 0, the PRACH occupies a middle 1.08MHz bandwidth (72 subcarriers) in the frequency domain, and occupies a total of 14 symbols of the first uplink subframe in the time domain, as shown in fig. 3.
However, when co-channel interference is encountered, both PRACH corresponding to two Preamble format types in the prior art are interfered, and a specific interference situation is shown in fig. 4, a TD-LTE network only slightly interferes with Up and the first uplink symbol in a daily period, but the interference level is generally below-110 dBm, and the influence on the network performance is not great; when the interference is suffered from the same frequency interference in a long distance, the uplink symbol 7 is not reduced to be lower than-105 dBm, UpPTS _ symbol 1, UpPTS _ symbol 2 and UL _ symbol 1 to UL _ symbol 6 are all subjected to interference of different degrees, and the intensity of the interference level is in a descending trend from front to back.
Therefore, it can be known from experimental statistics that strong interference is encountered on two symbols of UpPTS when preamble format is set to 4; under the condition that the preamble format is set to 0, the first 6 symbols of the UP subframe suffer from strong interference, which seriously affects the radio access performance and the LTE user perception.
In order to solve the influence caused by co-channel interference, an embodiment of the present invention provides an interference preamble sequence format, and random access is implemented based on the preamble sequence format, specifically, referring to fig. 5, an embodiment of the present invention provides a flow diagram of a random access method, and specifically, an implementation method includes:
step S101, the base station judges whether the same frequency interference exists at present.
Step S102, if there is co-channel interference, the base station sends a system message carrying an interference preamble sequence format to UE under the base station, wherein the interference preamble sequence format is used for indicating that a time domain resource occupied by the PRACH of the UE is from an ith symbol to an (i + n) th symbol of at least a first uplink subframe of each half frame in a radio frame, an uplink interference level value of the ith symbol is smaller than a first threshold value, and n is a positive integer not greater than 14.
Step S103, the base station receives a lead code for random access sent by the UE on the time domain resource indicated by the interference lead format.
Step S104, if the base station correctly demodulates the lead code, a random access response is sent to the UE.
Considering that the interference level value collected by the network side changes when the base station suffers from co-channel interference, the base station can judge whether the base station is in a co-channel interference state according to the interference level value of the network side, and specifically, the base station obtains an uplink interference level value corresponding to each symbol in a symbol group of each subframe in a wireless frame;
aiming at an uplink subframe in a wireless frame, the base station compares an uplink interference level value corresponding to each symbol in a symbol group of the uplink subframe with the first threshold, if the uplink interference level values corresponding to m continuous symbols are larger than the first threshold, the base station is judged to have co-channel interference, and m is a positive integer not larger than 14;
or,
aiming at a special subframe in a wireless frame, the base station compares uplink interference level values respectively corresponding to symbols of uplink pilot frequency time slots in the special subframe with a first threshold value, and if the uplink interference level values respectively corresponding to the symbols of the uplink pilot frequency time slots in the special subframe are larger than the first threshold value, the base station is judged to have co-channel interference.
For example, when the base station adopts an uplink PRACH channel with a Preamble format type of 4, when co-channel interference is encountered, 2 symbols occupying uppts in a time domain of the PRACH all encounter strong interference, and uplink interference level values are all greater than-110 dBm, so that the base station can be determined to be in a co-channel interference state at this time; in addition, when the base station adopts an uplink PRACH channel with a Preamble format type of 0, when co-channel interference is encountered, the PRACH time domain occupies a total of 14 symbols (symbols) of a first uplink subframe, the first 6 symbols all encounter strong interference, and uplink interference level values of the first 6 symbols are all greater than-110 dBm, so that it can be determined that the base station is in a co-channel interference state at this time. Of course, other co-channel interference determination methods in the prior art are also applicable, and are not described herein again.
When the base station judges that the base station is in the same frequency interference state, the occupied position of the PRACH on the time domain needs to be adjusted to solve the influence caused by the same frequency interference, specifically, the solution is to set a new leader sequence format, the embodiment of the invention is defined as an interference leader sequence format, and the interference leader sequence format comprises a length TcpHas a Cyclic Prefix (CP) and a length TSEQWherein Tcp is 15456Ts, TSEQWas 12288 Ts.
In the TD-LTE system, the interfering preamble sequence format indicates that time domain resources occupied by a physical random access channel PRACH of the UE are from the 7 th symbol to the 14 th symbol of a first uplink subframe of each half frame in a radio frame, where the time domain resources occupied by the PRACH are as shown in fig. 6. In this way, co-channel interference of each symbol does not need to be considered in real time, but the co-channel interference can be avoided by the interference preamble sequence format agreed by the base station and the UE, so that the efficiency of the system can be further improved.
Because in the TD-LTE system, the subframe configuration of one radio frame of the TD-LTE system adopts mode 2, and mode 2 includes: the 1 radio frame includes 6 downlink subframes, 2 uplink subframes and 2 special subframes. Based on the characteristics of the subframe in the mode 2 adopted by the TD-LTE system, each half frame comprises an uplink subframe, when co-channel interference is encountered, the first 6 symbols in the uplink subframe of each half frame in a wireless frame of the TD-LTE system are interfered, and the interference level value of the last 8 symbols is below-110 dBm, so that the time domain resources occupied by the PRACH are adjusted to be the 7 th symbol to the 14 th symbol of the first uplink subframe of each half frame in the wireless frame, and the interference level strength of the PRACH channel can be effectively reduced.
In addition, if in the TD-LTE system, the subframe configuration of one radio frame in the TD-LTE system adopts mode 1, and mode 1 includes: the 1 radio frame includes 4 downlink subframes, 4 uplink subframes, and 2 special subframes. Based on the characteristics of the subframes in the mode 1 adopted by the TD-LTE system, each half frame comprises two uplink subframes, when co-channel interference is encountered, the first 6 symbols in the uplink subframe of each half frame in a wireless frame of the TD-LTE system are interfered, and the interference level value of the last 8 symbols is below-110 dBm, so that the time domain resources occupied by the PRACH are adjusted to be the 7 th symbol to the 14 th symbol of the first uplink subframe and the second uplink subframe of each half frame in the wireless frame, and the interference level intensity of the PRACH channel can be effectively reduced.
After the format of the interference preamble sequence is determined, the base station side and the UE side agree to default the PRACH resource of the interference preamble sequence format through a protocol. Because the PRACH resources in the above-mentioned set format are agreed by both the base station and the UE, the UE directly selects randomly from the agreed PRACH resources in the specific format during the process of initiating random access, and sends a preamble on the selected PRACH resource. As shown in fig. 7, the random access procedure of the UE specifically includes:
step S201, a UE receives a system message carrying an interference preamble format sent by a base station, wherein the interference preamble format is used for indicating that a time domain resource occupied by a Physical Random Access Channel (PRACH) of the UE is from an ith symbol to an (i + n) th symbol of at least a first uplink subframe of each half frame in a radio frame, an uplink interference level value of the ith symbol is less than a first threshold, and n is a positive integer not greater than 14.
Step S202, the UE sends lead codes used for random access on the PRACH resources, so that the base station sends random access response to the UE corresponding to the lead codes which are correctly demodulated according to the lead codes of each UE.
After the UE sends the preamble through the random access method of the embodiment of the present invention, the base station may demodulate and detect the preamble sent by each UE on the PRACH resource configured for the UE, and send a Random Access Response (RAR) to the UE corresponding to the correctly demodulated preamble. The base station needs to calculate an RA-RNTI (random access-Radio Network Temporary Identifier) according to the PRACH resource used by the preamble, perform CRC (Cyclic Redundancy Check) Check on the PDCCH using the RA-RNTI, and then transmit the random access response on the PDSCH scheduled by the PDCCH, where a specific transmission process is the same as in the prior art and is not described herein again.
By the method of the embodiment of the invention, the UE sends the lead code on the PRACH resource which is configured by the base station and has the specific format of the interference leader sequence format, thereby solving the problem of difficult UE access under the same frequency interference, improving the access success rate of the UE and improving the access performance of the whole system.
Based on the same technical concept, the embodiment of the invention also provides a base station, and the base station can execute the method embodiment. As shown in fig. 8, the base station provided in the embodiment of the present invention includes: a judging unit 301, a system message sending unit 302, a receiving unit 303, and a random access response sending unit 304, wherein:
a judging unit 301, configured to judge whether there is co-channel interference currently;
a system message sending unit 302, configured to send a system message carrying an interference preamble format to a UE under the base station if co-channel interference exists, where the interference preamble sequence format is used to indicate that a time domain resource occupied by a physical random access channel PRACH of the UE is an ith symbol to an i + nth symbol of at least a first uplink subframe of each half frame in a radio frame, where an uplink interference level value of the ith symbol is less than a first threshold, and n is a positive integer not greater than 14;
a receiving unit 303, configured to receive, on the time domain resource indicated by the interference preamble format, a preamble sent by the UE for performing random access;
a random access response sending unit 304, configured to send a random access response to the UE if the preamble is correctly demodulated.
Considering that when the base station suffers from co-channel interference, the interference level value collected by the network side may change, and therefore, it may be determined whether the base station is in a state of co-channel interference according to the interference level value of the network side, specifically, the determining unit 301 is specifically configured to:
acquiring uplink interference level values corresponding to each symbol in a symbol group of each subframe in a wireless frame;
aiming at an uplink subframe in a wireless frame, comparing an uplink interference level value corresponding to each symbol in a symbol group of the uplink subframe with the first threshold, and if the uplink interference level values corresponding to m continuous symbols are greater than the first threshold, judging that the base station has co-channel interference, wherein m is a positive integer not greater than 14;
or,
and aiming at a special subframe in a wireless frame, comparing uplink interference level values respectively corresponding to symbols of an uplink pilot time slot in the special subframe with a first threshold, and if the uplink interference level values respectively corresponding to the symbols of the uplink pilot time slot in the special subframe are greater than the first threshold, judging that the base station has co-channel interference.
The interference preamble sequence format indicates that time domain resources occupied by a Physical Random Access Channel (PRACH) of the UE are from the 7 th symbol to the 14 th symbol of a first uplink subframe of each half frame in a wireless frame.
For example, when the base station adopts an uplink PRACH channel with a Preamble format type of 4, when co-channel interference is encountered, 2 symbols occupying uppts in a time domain of the PRACH all encounter strong interference, and uplink interference level values are all greater than-110 dBm, so that the base station can be determined to be in a co-channel interference state at this time; in addition, when the base station adopts an uplink PRACH channel with a Preamble format type of 0, when co-channel interference is encountered, the PRACH time domain occupies a total of 14 symbols (symbols) of a first uplink subframe, the first 7 symbols all encounter strong interference, and uplink interference level values of the first 7 symbols are all greater than-110 dBm, so that it can be determined that the base station is in a co-channel interference state at this time. Of course, other co-channel interference determination methods in the prior art are also applicable, and are not described herein again.
When the base station judges that the base station is in the same frequency interference state, the occupied position of the PRACH on the time domain needs to be adjusted to solve the influence caused by the same frequency interference, specifically, the solution is to set a new leader sequence format, the embodiment of the invention is defined as an interference leader sequence format, and the interference leader sequence format comprises a length TcpHas a Cyclic Prefix (CP) and a length TSEQWherein Tcp is 15456Ts, TSEQWas 12288 Ts.
In the TD-LTE system, the interfering preamble sequence format indicates that time domain resources occupied by a physical random access channel PRACH of the UE are from the 7 th symbol to the 14 th symbol of a first uplink subframe of each half frame in a radio frame, where the time domain resources occupied by the PRACH are as shown in fig. 6.
Because in the TD-LTE system, the subframe configuration of one radio frame of the TD-LTE system adopts mode 2, and mode 2 includes: the 1 radio frame includes 6 downlink subframes, 2 uplink subframes and 2 special subframes. Based on the characteristics of the subframe in the mode 2 adopted by the TD-LTE system, each half frame comprises an uplink subframe, when co-channel interference is encountered, the first 7 symbols in the uplink subframe of each half frame in a wireless frame of the TD-LTE system are interfered, and the interference level value of the last 7 symbols is below-110 dBm, so that the time domain resources occupied by the PRACH are adjusted to be the 7 th symbol to the 14 th symbol of the first uplink subframe of each half frame in the wireless frame, and the interference level intensity of the PRACH channel can be effectively reduced.
In addition, if in the TD-LTE system, the subframe configuration of one radio frame in the TD-LTE system adopts mode 1, and mode 1 includes: the 1 radio frame includes 4 downlink subframes, 4 uplink subframes, and 2 special subframes. Based on the characteristics of the subframes in the mode 1 adopted by the TD-LTE system, each half frame comprises two uplink subframes, when co-channel interference is encountered, the first 7 symbols in the uplink subframe of each half frame in a wireless frame of the TD-LTE system are interfered, and the interference level value of the last 7 symbols is below-110 dBm, so that the time domain resources occupied by the PRACH are adjusted to be the 7 th to 14 th symbols of the first uplink subframe and the second uplink subframe of each half frame in the wireless frame, and the interference level intensity of the PRACH channel can be effectively reduced.
After the format of the interference preamble sequence is determined, the base station side and the UE side agree to default the PRACH resource of the interference preamble sequence format through a protocol. Because the PRACH resources in the above-mentioned set format are agreed by both the base station and the UE, the UE directly selects randomly from the agreed PRACH resources in the specific format during the process of initiating random access, and sends a preamble on the selected PRACH resource. The present invention also provides a UE, referring to fig. 9, the UE includes: a receiving unit 401 and a transmitting unit 402, wherein:
a receiving unit 401, configured to receive a system message carrying an interference preamble format sent by a base station, where the interference preamble sequence format is used to indicate that a time domain resource occupied by a physical random access channel PRACH of a UE is an ith symbol to an i + n th symbol of at least a first uplink subframe of each half frame in a radio frame, where an uplink interference level value of the ith symbol is less than a first threshold, and n is a positive integer not greater than 14;
a sending unit 402, configured to send a preamble for performing random access on the PRACH resource, so that the base station sends a random access response to the UE corresponding to the correctly demodulated preamble according to the preamble of each UE.
After the UE sends the preamble through the random access method of the embodiment of the present invention, the base station may demodulate and detect the preamble sent by each UE on the PRACH resource configured for the UE, and send a random access Response (RA Response, RAR) to the UE corresponding to the correctly demodulated preamble. The base station needs to calculate a random access-Radio Network Temporary Identifier (RA-RNTI) according to the PRACH resource used by the preamble, perform CRC check on the PDCCH using the RA-RNTI, and then transmit the random access response on the PDSCH scheduled by the PDCCH, where a specific transmission process is the same as that in the prior art and is not described herein.
In summary, in one aspect of the embodiments of the present invention, a base station determines whether co-channel interference exists currently, and if co-channel interference exists, sends a system message carrying an interference preamble sequence format to a user equipment UE under the base station, where the interference preamble format in the system message is a preamble sequence format pre-agreed by the base station and a terminal, and the preamble sequence format is characterized in that a time domain resource occupied by a PRACH is an ith symbol to an i + n symbol of at least a first uplink subframe of each half frame in a radio frame, and an uplink interference level value of the ith symbol is smaller than a first threshold; on the other hand, the UE sends a preamble on the PRACH agreed to the interference preamble sequence format, and the base station sends a random access response to the UE after receiving the preamble and completing correct demodulation. Therefore, when the UE uses the PRACH with the interfering preamble sequence format defined in the embodiment of the present invention to send the preamble for access, the access success rate of the UE can be improved under the same frequency interference condition, and the access performance of the whole system can be improved.
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 changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations 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 include such modifications and variations.
Claims (10)
1. A random access method, comprising:
the base station judges whether the same frequency interference exists at present;
if the same frequency interference exists, the base station sends a system message carrying an interference leader sequence format to User Equipment (UE) under the base station, wherein the interference leader sequence format is used for indicating that time domain resources occupied by a Physical Random Access Channel (PRACH) of the UE are from the ith symbol to the (i + n) th symbol of at least a first uplink subframe of each half frame in a wireless frame, the uplink interference level value of the ith symbol is less than a first threshold value, and n is a positive integer not greater than 14;
the base station receives a lead code which is sent by UE and used for random access on the time domain resource indicated by the interference lead sequence format;
and if the base station correctly demodulates the lead code, sending a random access response to the UE.
2. The method of claim 1, wherein the interfering preamble sequence format indicates that a Physical Random Access Channel (PRACH) of the UE occupies time domain resources of 7 th to 14 th symbols of a first uplink subframe of each half frame in a radio frame.
3. The method of claim 2, wherein the base station determining whether co-channel interference currently exists comprises:
the base station acquires an uplink interference level value corresponding to each symbol in a symbol group of each subframe in a wireless frame;
aiming at an uplink subframe in a wireless frame, the base station compares an uplink interference level value corresponding to each symbol in a symbol group of the uplink subframe with the first threshold, if the uplink interference level values corresponding to m continuous symbols are larger than the first threshold, the base station is judged to have co-channel interference, and m is a positive integer not larger than 14;
or,
aiming at a special subframe in a wireless frame, the base station compares uplink interference level values respectively corresponding to symbols of uplink pilot frequency time slots in the special subframe with a first threshold value, and if the uplink interference level values respectively corresponding to the symbols of the uplink pilot frequency time slots in the special subframe are larger than the first threshold value, the base station is judged to have co-channel interference.
4. The method of claim 1, wherein the PRACH resource comprises a Cyclic Prefix (CP) and a preamble sequence code, and wherein the CP is determined according to a cell radius covered by the base station.
5. A random access method, comprising:
the method comprises the steps that UE receives a system message which is sent by a base station and carries an interference leader sequence format, wherein the interference leader sequence format is used for indicating that time domain resources occupied by a Physical Random Access Channel (PRACH) of the UE are from the ith symbol to the (i + n) th symbol of at least a first uplink subframe of each half frame in a wireless frame, the uplink interference level value of the ith symbol is smaller than a first threshold value, and n is a positive integer not larger than 14;
and the UE sends a lead code for random access on the PRACH resource so that the base station sends a random access response to the UE corresponding to the lead code which is correctly demodulated according to the lead code of each UE.
6. A base station, comprising:
the judging unit is used for judging whether the same frequency interference exists at present;
a system message sending unit, configured to send a system message carrying an interference preamble sequence format to a UE under the base station if co-channel interference exists, where the interference preamble sequence format is used to indicate that a time domain resource occupied by a physical random access channel PRACH of the UE is an ith symbol to an i + nth symbol of at least a first uplink subframe of each half frame in a radio frame, where an uplink interference level value of the ith symbol is less than a first threshold, and n is a positive integer not greater than 14;
a receiving unit, configured to receive a preamble sent by a UE for performing random access on a time domain resource indicated by the interfering preamble sequence format;
and a random access response sending unit, configured to send a random access response to the UE if the preamble is correctly demodulated.
7. The base station of claim 6, wherein the interfering preamble sequence format indicates that a Physical Random Access Channel (PRACH) of the UE occupies time domain resources from a 7 th symbol to a 14 th symbol of a first uplink subframe of each half frame in a radio frame.
8. The base station of claim 6, wherein the determining unit is specifically configured to:
acquiring uplink interference level values corresponding to each symbol in a symbol group of each subframe in a wireless frame;
aiming at an uplink subframe in a wireless frame, comparing an uplink interference level value corresponding to each symbol in a symbol group of the uplink subframe with the first threshold, and if the uplink interference level values corresponding to m continuous symbols are greater than the first threshold, judging that the base station has co-channel interference, wherein m is a positive integer not greater than 14;
or,
and aiming at a special subframe in a wireless frame, comparing uplink interference level values respectively corresponding to symbols of an uplink pilot time slot in the special subframe with a first threshold, and if the uplink interference level values respectively corresponding to the symbols of the uplink pilot time slot in the special subframe are greater than the first threshold, judging that the base station has co-channel interference.
9. The base station of claim 6, wherein the PRACH resource comprises a Cyclic Prefix (CP) and a preamble sequence code, and wherein the CP is determined according to a cell radius covered by the base station.
10. A user equipment, UE, characterized in that the apparatus comprises:
a receiving unit, configured to receive a system message carrying an interference preamble sequence format sent by a base station, where the interference preamble sequence format is used to indicate that a time domain resource occupied by a physical random access channel PRACH of a UE is an ith symbol to an i + n th symbol of at least a first uplink subframe of each half frame in a radio frame, where an uplink interference level value of the ith symbol is less than a first threshold, and n is a positive integer not greater than 14;
and the sending unit is used for sending the lead code used for random access on the PRACH resource so that the base station sends a random access response to the UE corresponding to the correctly demodulated lead code according to the lead code of each UE.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201511019645.0A CN106937400B (en) | 2015-12-29 | 2015-12-29 | Random access method, base station and user equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201511019645.0A CN106937400B (en) | 2015-12-29 | 2015-12-29 | Random access method, base station and user equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN106937400A CN106937400A (en) | 2017-07-07 |
| CN106937400B true CN106937400B (en) | 2020-02-18 |
Family
ID=59441485
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201511019645.0A Active CN106937400B (en) | 2015-12-29 | 2015-12-29 | Random access method, base station and user equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN106937400B (en) |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2019054311A (en) * | 2016-01-29 | 2019-04-04 | シャープ株式会社 | Terminal, base station device and communication metho |
| US11382125B2 (en) | 2017-08-07 | 2022-07-05 | Beijing Xiaomi Mobile Software Co., Ltd. | Data transmission method, device and computer readable storage medium |
| WO2019028793A1 (en) * | 2017-08-10 | 2019-02-14 | 华为技术有限公司 | Random access preamble transmitting method and device |
| WO2019049352A1 (en) * | 2017-09-08 | 2019-03-14 | 株式会社Ｎｔｔドコモ | Base station device and user device |
| PL3713362T3 (en) * | 2017-11-16 | 2024-07-08 | Ntt Docomo, Inc. | User device and base station device |
| RU2747111C9 (en) * | 2018-01-11 | 2021-07-15 | Нтт Докомо, Инк. | User device and base station |
| CN110098903B (en) * | 2018-01-30 | 2021-10-22 | 普天信息技术有限公司 | Uplink pilot frequency transmission method, user equipment and base station |
| EP3758426B1 (en) * | 2018-02-20 | 2023-06-28 | Ntt Docomo, Inc. | Terminal and base station apparatus |
| CN110198567B (en) * | 2018-02-26 | 2021-11-26 | 深圳市中兴微电子技术有限公司 | Random access detection method and device |
| CN109451585B (en) * | 2018-04-04 | 2020-07-14 | 华为技术有限公司 | Communication method and device |
| WO2019213972A1 (en) * | 2018-05-11 | 2019-11-14 | 华为技术有限公司 | Method and apparatus for transmitting random access preamble |
| CN111278151B (en) * | 2018-12-24 | 2021-09-28 | 维沃移动通信有限公司 | Random access method, network side equipment and terminal |
| CN114615683B (en) * | 2020-12-08 | 2023-08-15 | 中国移动通信集团山西有限公司 | Method, device, equipment and storage medium for optimizing random access |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101309109A (en) * | 2008-06-20 | 2008-11-19 | 中兴通讯股份有限公司 | Method for mapping physical stochastic access channel of TDD system to physical resource |
| CN101345580A (en) * | 2008-08-22 | 2009-01-14 | 中兴通讯股份有限公司 | Transmission method and device of random access channel |
| CN101873714A (en) * | 2009-04-27 | 2010-10-27 | 中兴通讯股份有限公司 | Method and system for configuring circular shifting restrictions of physical random access channel |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8130667B2 (en) * | 2008-09-19 | 2012-03-06 | Texas Instruments Incorporated | Preamble group selection in random access of wireless networks |
-
2015
- 2015-12-29 CN CN201511019645.0A patent/CN106937400B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101309109A (en) * | 2008-06-20 | 2008-11-19 | 中兴通讯股份有限公司 | Method for mapping physical stochastic access channel of TDD system to physical resource |
| CN101345580A (en) * | 2008-08-22 | 2009-01-14 | 中兴通讯股份有限公司 | Transmission method and device of random access channel |
| CN101873714A (en) * | 2009-04-27 | 2010-10-27 | 中兴通讯股份有限公司 | Method and system for configuring circular shifting restrictions of physical random access channel |
Also Published As
| Publication number | Publication date |
|---|---|
| CN106937400A (en) | 2017-07-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106937400B (en) | Random access method, base station and user equipment | |
| US11197316B2 (en) | Terminal device, base station device, and radio communication method | |
| CN107926034B (en) | Random access procedure for MTC operations | |
| EP2869654B1 (en) | Method of handling random access in wireless communication system | |
| CN105557056B (en) | Communication device and method for improving transmission of random access messages | |
| EP3266253B1 (en) | Repetition level coverage enhancement techniques for physical random access channel transmissions | |
| EP1949565B1 (en) | Random access dimensioning methods and procedures for frequency division multiplexing access systems | |
| KR102687897B1 (en) | Random access method and device | |
| US8559362B2 (en) | Random access channel hopping for frequency division multiplexing access systems | |
| US8427971B2 (en) | Enhancement of LTE random access procedure | |
| CN112020875A (en) | Beam failure recovery in conjunction with switched BWP | |
| JP2020519089A (en) | Method for performing random connection process and apparatus therefor | |
| KR20170109569A (en) | Method for transmitting an uplink signal, user equipment and base station | |
| CN115361745A (en) | Method and apparatus for performing contention-based random access in carrier frequency | |
| EP3634073B1 (en) | Communication connection method and base station | |
| EP3177092A1 (en) | Terminal device, base station device, communication method and integrated circuit | |
| US11218979B2 (en) | Power control method and apparatus | |
| CN108207027B (en) | Random access method and equipment | |
| EP3177084A1 (en) | Terminal device, base station device, communications method and integrated circuit | |
| US10271306B2 (en) | Data transmission method, apparatus, and system | |
| CN110463132B (en) | Method for allocating resources to a plurality of signals in wireless communication system and apparatus therefor | |
| CN114208300A (en) | Method and device for receiving and sending random access response in two-step random access | |
| US20210218520A1 (en) | Data transmission method, network device, and terminal device | |
| US20230254746A1 (en) | Method and device in nodes used for wireless communication |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |