CN103458528B - Accidental access method based on competition and equipment - Google Patents

Abstract

The present invention relates to communication technical field, disclose a kind of accidental access method based on competition and equipment, the method includes: the targeting sequencing that detection user equipment (UE) sends, determine time domain and the frequency domain position of described targeting sequencing, wherein, the frequency domain width that described targeting sequencing takies is less than 6 Resource Block RB；Physical Downlink Shared Channel PDSCH sends accidental access response, wherein, the time domain of the RB that the targeting sequencing of described accidental access response instruction described UE use and described targeting sequencing take and frequency domain position.Utilize the present invention, PRACH in LTE system can be strengthened and cover, it is ensured that the communication quality of Cell Edge User.

Description

Contention-based random access method and device

technical field

The present invention relates to the field of communication technology, in particular to a contention-based random access method and equipment.

Background technique

The Long Term Evolution (LTE) technology of the third generation mobile communication (3rd Generation, 3G) has now entered the commercial stage from the research stage. In the deployment of LTE networks, in order to save costs and make network deployment more convenient, Operators hope that the LTE network can use the same site as the existing Universal Mobile Telecommunications System (UMTS) network. In order to ensure the communication quality of cell edge users, it is required that the LTE network and the UMTS network can achieve the same coverage. The LTE network divides different channels at the physical layer to carry different information. To evaluate the coverage of LTE, it is necessary to evaluate the coverage of these channels separately, identify the channels with limited coverage through comparison, and then consider ways to enhance the coverage of the channels.

In the prior art, a method of calculating a maximum coupling loss (Maximum Coupling Loss, MCL) may be used to evaluate the coverage of each channel of the LTE. MCL is defined as the link loss between the user equipment (UserEquipment, UE) antenna and the base station (eNodeB) antenna, including factors such as antenna gain, path loss, and shadow fading. The MCL is the limit value of the connection loss at which the service can be provided, and is therefore defined as the coverage of the service.

Through simulation and calculation, it can be concluded that when the Physical Random Access Channel (PRACH) adopts Format 2, although the 839-long preamble sequence is repeatedly sent to improve the detection performance, the calculated MCL is still relatively low. Therefore, it is necessary to consider enhancing the coverage of the PRACH, but there is no effective solution for enhancing the coverage of the PRACH in the prior art.

Contents of the invention

Aiming at the problems in the above-mentioned prior art, the present invention provides a contention-based random access method and equipment to solve the problem of limited PRACH coverage in the LTE system.

For this reason, the present invention provides following technical scheme:

A contention-based random access method, comprising:

Detecting the preamble sequence sent by the user equipment UE, and determining the time domain and frequency domain position of the preamble sequence, wherein the frequency domain width occupied by the preamble sequence is less than 6 resource blocks RB;

A random access response is sent on the physical downlink shared channel PDSCH, where the random access response indicates the preamble used by the UE and the time domain and frequency domain positions of the RBs occupied by the preamble.

A contention-based random access method, comprising:

Selecting a preamble sequence in a random access process, where the frequency domain width occupied by the preamble sequence is less than 6 resource blocks RB;

Send the preamble.

A network device comprising:

The detection unit is configured to detect the preamble sequence sent by the user equipment UE, and determine the time domain and frequency domain position of the preamble sequence; the frequency domain width occupied by the preamble sequence is less than 6 resource blocks RB;

The sending unit is configured to send a random access response on the physical downlink shared channel PDSCH, the random access response indicates the preamble used by the user equipment, and the time domain and frequency domain positions of the RB occupied by the preamble.

A user equipment, comprising:

A processing unit, configured to select a preamble in a random access process, where the frequency domain width occupied by the preamble is less than 6 RBs;

A sending unit, configured to send the preamble sequence.

The contention-based random access method and equipment provided by the present invention enhance coverage by reducing the number of resource blocks (Resource Block, RB) used by each user's PRACH sequence and increasing the signal-to-noise ratio in the case of full-power transmission, and solve the problem of LTE The system PRACH coverage is limited. Moreover, the random access response sent by the eNodeB to the UE indicates the preamble used and the time domain and frequency domain positions of the RBs occupied by the preamble, which ensure the random access process of the UE and cell edge users communication quality.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings that are required in the embodiments. Obviously, the accompanying drawings in the following description are only described in the present invention For some embodiments of the present invention, those skilled in the art can also obtain other drawings according to these drawings.

FIG. 1 is a schematic diagram of a sequence format of an existing PRACH;

FIG. 2 is a flow chart of implementing a contention-based random access method on the network side according to an embodiment of the present invention;

FIG. 3 is a flow chart of implementing a contention-based random access method on the user equipment side according to an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of a network device according to an embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a user equipment according to an embodiment of the present invention.

detailed description

In order to enable those skilled in the art to better understand the solutions of the embodiments of the present invention, the embodiments of the present invention will be further described in detail below in conjunction with the drawings and implementations.

The calculation process of the MCL in the prior art will be briefly described below.

MCL and carrier frequency are independent, and are defined as:

Uplink MCL = maximum uplink transmit power - eNodeB sensitivity;

Downlink MCL = downlink maximum transmit power - UE sensitivity.

MCL can be evaluated through link budget analysis, and the calculation process is as follows:

MCL = transmit power - receiver sensitivity;

Receiver sensitivity = equivalent noise power + required signal-to-noise ratio SINR;

Equivalent noise power = thermal noise density + receiver noise figure + interference margin + 10log (occupied channel bandwidth).

Wherein, the value of the required Signal to Interference plus Noise Ratio (SINR) needs to be obtained through link simulation of each channel. The MCL of each channel is calculated and compared, and the channel with the smaller MCL value is the channel with limited coverage.

From the calculation process of the above MCL, it can be seen that when the PRACH is transmitted at full power, the transmission power is fixed at 23dBm, and the larger the occupied channel bandwidth, the greater the calculated equivalent noise power, resulting in a smaller calculated MCL .

The resources of the LTE system are divided into multiple symbols in the time domain and divided into subcarriers in the frequency domain. A radio frame includes 10 subframes, and a normal subframe includes two time slots. The size of an RB is defined as 12 subcarriers in the frequency domain, and the length of a time slot in the time domain.

There are five types of sequences used by the existing PRACH, the duration of the sequence is T _SEQ , and the duration of a cyclic prefix (Cyclic Prefix, CP) is T _CP , as shown in FIG. 1 . The T _SEQ and _TCP stipulations in various formats are shown in Table 1 below, that is, the time domain length of the PRACH is specified.

Table 2:

In Table 2, 5, 6, 7, and 8 represent serial numbers of special subframe configurations.

In the frequency domain, each PRACH sequence occupies 1.08MHz, that is, 6 RBs and a width of 72 subcarriers. In the case of frequency division duplex (Frequency Division Duplex, FDD), at most one PRACH sequence is transmitted in each subframe, that is, there is no frequency division. In the case of Time Division Duplex (TDD), multiple PRACH sequences are allowed to be sent in one subframe, up to 6, that is, multiple PRACH sequences are frequency-divided in the frequency domain. The parameter prach-ConfigurationIndex configured by the upper layer indicates the time position, time density and frequency position where the PRACH is allowed to send.

In the prior art, a total of 64 PRACH sequences can be used as preamble sequences in one cell. There are two modes in the random access process, namely contention-based random access and non-contention-based random access. The 64 PRACH sequences are further divided into two parts, which are used for contention-based random access and non-contention-based random access. The network side notifies the UE of the preamble sequence used for contention-based random access (64 minus Ncf, where Ncf is the number of sequences reserved by the network side for non-contention-based random access) through a broadcast channel.

When initiating a contention random access process, the preamble sequence used by the UE is one selected from the 64 minus Ncf PRACH sequences.

The sequence lengths of various formats are shown in Table 2.

Table 2:

Sequence format (Format) sequence length 0–3 839 4 139

The PRACH uses a smaller subcarrier spacing, the subcarrier spacing of sequence formats 0-3 is 1250 Hz, and the subcarrier spacing of format 4 is 7500 Hz.

Since the PRACH occupies a frequency domain width of 6 RBs in the frequency domain, the received equivalent noise power is relatively large, which results in a small MCL corresponding to the PRACH, which affects the coverage of the PRACH.

Through the above-mentioned analysis of the reasons for the limited coverage of the existing PRACH, the embodiment of the present invention proposes a method and device for enhancing PRACH coverage, by reducing the frequency domain width occupied by each UE for the PRACH channel, and increasing the full power transmission situation Lower SNR to enhance PRACH coverage.

As shown in Fig. 2, it is the implementation flowchart of the method for enhancing PRACH coverage in the embodiment of the present invention on the network side, including the following steps:

Step 201: Detect the preamble sent by the UE to determine the position of the preamble in the time domain and frequency domain, and the width of the frequency domain occupied by the preamble is less than 6 RBs.

In the embodiment of the present invention, in order to enhance PRACH coverage, the frequency domain width of the preamble sequence is reduced, for example, the frequency domain width occupying 6 RBs is reduced to the frequency domain width occupying 1 RB, of course, It may also be a frequency domain width of n*RB, where 1<n<6, which is not limited in this embodiment of the present invention. For the convenience of description, in the following description, each preamble sequence occupies a frequency domain width of 1 RB as an example for illustration.

Since the design of the sequence format Format4 is only applicable to the short uplink special domain in TDD mode, that is, the UpPTS (Uplink Pilot Time Slot, uplink pilot time slot) area, and it is applied to small-sized cells, it is not necessary to apply it when considering coverage issues Format4 performs random access. Therefore, in the embodiment of the present invention, the subcarrier spacing can be kept consistent with the subcarrier spacing of the original Format0-3, which is 1250 Hz.

Considering that the subcarrier spacing of the LTE system under other channels is 15kHz, the width of one RB in the frequency domain is 12 subcarriers. Therefore, for the subcarrier spacing of 1250Hz used by PRACH, the available frequency domain width of one RB is 144 subcarriers. Carrier (ie 15000*12/1250=144). If the length of the preamble sequence is set to 139, that is, 139 subcarriers are occupied (2.5 subcarriers are used as guard bands on both sides of the subcarrier), and the time domain duration of a preamble sequence is 1/1250=0.8ms. The preamble sequence with a length of 139 may be sent within 1 Transmission Time Interval (Transmission Time Interval, TTI) in the time domain and 1 RB width among 6 RBs in the frequency domain.

In the embodiment of the present invention, the selection and transmission of the preamble sequence may be implemented in various manners, which will be described in detail later.

Step 202: Send a random access response on a physical downlink shared channel (Physical Downlink Shared Channel, PDSCH), where the random access response indicates the preamble used by the UE and the timing of the RB occupied by the preamble domain and frequency domain locations.

It should be noted that the random access response may also include: a timing alignment instruction, an initial uplink resource permitted for transmission in a subsequent message 3 (Message3), a temporary cell radio network temporary identifier (Cell Radio Network Temporary Identifier, C- RNTI) and so on. The meanings of these information are the same as those in the prior art, and will not be described in detail here.

The process of random access for users is also the same as that of the prior art, roughly as follows:

In the contention-based random access process, after sending the preamble, the UE expects to receive the above-mentioned random access response within a time window. If the UE does not receive a random access response within the set time window, it will retransmit the preamble.

After the UE receives the random access response within the set time window, it will schedule the first uplink transmission on the Physical Uplink Shared Channel (PUSCH), that is, Message3, using Hybrid Automatic Repeat Request (Hybrid Automatic Repeat Request, HARQ) technology, to transmit exact random access process messages, such as Radio Resource Control (Radio Resource Control, RRC) link request, tracking area update or scheduling request, etc., including the above temporary C-RNTI and C-RNTI in Message 3 RNTI, or include the above-mentioned temporary C-RNTI and UE ID, and Message 3 is scrambled with the above-mentioned temporary C-RNTI.

In the contention-based random access, since the UE randomly selects the preamble, there is a possibility that multiple UEs transmit the same preamble at the same time, that is, preamble collision may occur. In this case, the conflicting UE will receive the same temporary C-RNTI, so there will also be a conflict when the UE sends Message 3, resulting in the eNodeB being unable to successfully decode Message 3 sent by the conflicting UE, thus requiring the UE to interpret the Message 3. Perform retransmission. When the UE reaches the maximum number of HARQ retransmissions, it will start a new random access process.

If the eNodeB successfully decodes Message 3 of one of the conflicting UEs, the eNodeB sends a contention resolution message to the UE, and transmits the decoded C-RNTI or UE ID in the contention resolution message. After receiving the contention resolution message, the UE detects that the C-RNTI or UE ID in the contention resolution message is the same as its own C-RNTI or UE ID, then transmits HARQ feedback to the eNodeB, otherwise stops the current random access process, And start another random access procedure.

In the prior art, the random access response sent by the eNodeB on the PDSCH will carry a Random Access Preamble Index (RAPID) and a Random Access Radio Network Temporary Identifier (Random Access Radio Network Temporary Identifier, RA-RNTI), where:

RAPID is used to indicate the preamble sequence used by the UE. RAPID contains 6bit information and is used to indicate one of the 64 available PRACH sequences. That is to say, the RAPID in the random access response specifically indicates that the preamble sequence used by the UE is Which of the 64 PRACH sequences.

RA-RNTI=1+t_id+10*f_id, where:

t_id indicates the sequence number of the first subframe where the preamble sequence is located, 0≤t_id<10. Since the resources of the LTE system are divided into radio frames in the time domain, a radio frame includes 10 subframes, numbered 0-9, therefore, the time domain position of the preamble detected by the eNode can be indicated by using the subframe number.

f_id indicates the frequency domain positions of the 6 RBs occupied by the preamble sequence (these 6 RBs are continuous, and there are 6 types of starting positions in total). Specifically, the available RBs of each subframe may be numbered in ascending order of frequency in the frequency domain, 0≤f_id<6.

As mentioned above, in the embodiment of the present invention, each preamble may occupy only one RB in the frequency domain, and the subcarrier spacing remains consistent with that of the original Format0-3, which is 1250 Hz. The random access response sent by the eNodeB indicates the preamble used by the UE, and the time domain position and the frequency domain position of one RB occupied by the preamble. Therefore, in order to minimize changes to the existing system, the embodiment of the present invention can extend the existing two parameters RAPID and RA-RNTI, so that it can indicate the preamble used by the above-mentioned UE and the preamble occupied The information of the time-domain and frequency-domain positions of the RBs can be extended in multiple ways, which are related to the selection and transmission of the preamble sequence. The following example will describe this in detail.

In the following, the case where each PRACH sequence occupies a frequency domain width of 1 RB is taken as an example for description.

Embodiment one:

In this embodiment, a preamble sequence of length 139 is used.

The UE can randomly select the frequency domain width of one RB among the 6 RB frequency domain widths occupied by the existing PRACH channel for sending the preamble sequence, and different UEs can select different RB frequency domain positions. In this case, before the above step 201, the eNodeB can notify the UE of the PRACH sequences used for contention-based random access through the broadcast channel similarly to the prior art, and the UE randomly selects one of these PRACH sequences as the preamble sequence Sending, that is to say, the preamble sequence sent by the UE may be a sequence selected by the UE from the set of PRACH sequences used for contention-based random access. In this case, the UE only needs to send the preamble within one TTI. Correspondingly, before the above step 201, the eNodeB receives the preamble sequence with a length of 139 sent by the UE within one TTI.

Further, in order to further increase the coverage capability, the UE may send N (N≥1) PRACH sequences with a length of 139 in consecutive N TTIs, and the N PRACH sequences with a length of 139 may be the same or different. The frequency domain positions of the RBs occupied by the PRACH sequences in these TTIs are fixed. That is to say, when sending the PRACH sequence, the UE may send one sequence in one TTI, or may send different PRACH sequences in multiple consecutive TTIs.

It should be noted that the number N of consecutive PRACH sequences sent by the UE can be determined by the eNodeB according to factors such as the required coverage capability and the number of occupied resources in a specific application scenario, and notified to the UE through broadcast information. For UEs in the same cell, the number N of consecutively sent PRACH sequences remains the same.

In practical applications, the PRACH sequence sent continuously for N times may be defined as a sequence template, that is, the sequence template is composed of multiple PRACH sequences used for contention-based random access. In this case, the eNodeB may notify the UE of the sequence template used for the contention-based random access through the broadcast channel. It should be noted that the N PRACH sequences in the sequence template may be all identical, partially identical, or none of them identical. The UE randomly selects one of these sequence template sets as the preamble sequence to send. In this case, the UE needs to sequentially transmit the PRACH sequences in the sequence template in multiple consecutive TTIs, and the frequency domain positions of the RBs occupied by a PRACH sequence in each TTI are the same. Correspondingly, the eNodeB receives the PRACH sequence in the sequence template sent by the UE in multiple consecutive TTIs, and the frequency domain position of the RB occupied by a PRACH sequence sent in each TTI is the same.

Based on the above two methods of selecting and sending the preamble, after the eNodeB successfully detects the preamble, it sends a random access response to the UE. In the random access response, the RA-RNTI parameter can be used to instruct the UE to use The time domain and frequency domain positions of the RB set that the preamble sequence can occupy, where the RB set represents the set of 6 RBs selected by the UE for sending the preamble sequence in the prior art; RA-RNTI=1+t_id+10 *f_id, where t_id indicates the sequence number of the first subframe where the preamble is located, 0≤t_id<10, f_id indicates the frequency domain position of the RB set that the preamble can occupy, 0≤f_id<6. At the same time, the RAPID parameter is used to indicate the preamble sequence and the frequency domain position of the RB occupied by the preamble sequence in the RB set. Specifically, assuming that each PRACH sequence occupies the time domain width of 1 RB, then for the first transmission method, that is, the preamble sequence is only sent within one TTI, and the preamble sequence with a length of 139 is on one RB of one TTI For transmission, different UEs select different sequence shifts and different frequency domain positions, and the 6-bit information in the RAPID parameter indicates the PRACH sequence selected by the UE and the position of one of the 6 RBs in the prior art occupied by the PRACH sequence ;For the second transmission mode, the frequency domain of the length 139 sequence is fixed at one RB position, and the time domain is continuously transmitted N times, and different users select different sequence templates and different frequency domain positions, and the 6bit information in the RAPID parameter Indicates the sequence template selected by the UE and the position of one of the 6 RBs occupied by the PRACH sequence in the sequence template.

Embodiment two:

In this embodiment, a preamble sequence of length 839 is used.

Specifically, the preamble sequence can be divided into 6 parts, and only one RB position in the 6 RB widths is sent in the frequency domain, and only 1/6 part of the preamble sequence is sent in one TTI, and within six consecutive TTIs Different parts of the preambles are sent respectively, and the frequency domain positions of the RBs occupied by the preambles in these TTIs are the same. In the time domain, the duration of a preamble sequence is 6 times longer than the original one. Since 839 is not divisible by 6, in practical applications, 839 can be divided into 140*5+139, and the sequence length sent in the first 5 TTIs is 140, which is located in the middle of 144 available subcarriers in 1 RB in the frequency domain , leaving a guard band of 2 subcarriers on both sides; the sequence length sent in the latter TTI is 139, which is also located in the middle of 144 available subcarriers in 1 RB, leaving a guard band of 2.5 subcarriers on each side. The subcarrier spacing is 1250Hz.

Of course, the embodiment of the present invention is not limited to the above division method, and other division methods may also be used to divide the preamble sequence into 6 parts.

In this way, for the application scenario of Format0-1, the duration T _SEQ of extending PRACH is 24576*Ts*6 (Ts represents the smallest time unit, 30720Ts=1ms), which is about 6 TTIs, and the 839-long preamble sequence is as mentioned above Send once; for the application scenario of Format2-3, extend the duration T _SEQ of PRACH to 2*24576*Ts*6, which is about 12 TTIs, and send 839 long preamble sequences every 6 TTIs, that is, 839 long The preamble sequence is sent repeatedly.

In this embodiment, the UE can randomly select the frequency domain width of 1 RB among the 6 RB frequency domain widths occupied by the existing PRACH channel for sending the preamble sequence with a length of 839, and different UEs can Select different RB frequency domain positions. Correspondingly, before the above step 201, the eNodeB receives the preamble sequence with a length of 839 sent by the UE in multiple consecutive TTIs, wherein the frequency domain positions of RBs occupied by part of the preamble sequences received in each TTI are the same.

Based on the above-mentioned preamble sequence selection and transmission method, after the eNodeB successfully detects the preamble sequence, it sends a random access response to the UE. In the random access response, the RA-RNTI parameter can be used to indicate the UE to use The time domain and frequency domain position of the RB set that the preamble sequence can occupy, where the RB set represents the set of 6 RBs selected by the UE for sending the preamble sequence in the prior art; RA-RNTI=1+t_id+10* f_id, where t_id indicates the sequence number of the first subframe where the preamble is located, 0≤t_id<10, f_id indicates the frequency domain position of the RB set that the preamble can occupy, 0≤f_id<6. At the same time, the RAPID parameter is used to indicate the preamble sequence and the frequency domain position of the RB occupied by the preamble sequence in the RB set. Specifically, assuming that each PRACH sequence occupies the time domain width of 1 RB, the sequence with a length of 839 is sent on 1 RB of 6 TTIs, and different UEs select different sequence shifts and different frequency domain positions. RAPID The 6-bit information in the parameter is jointly determined by the shift sequence selected by the UE with a length of 839 and one RB selected from the 6 RBs.

It can be seen that in the above two embodiments, the 6-bit RAPID parameter in the random access response not only indicates which sequence the eNodeB receives, but also indicates which RB in the 6 RBs the eNodeB receives the sequence. In this way, there are less than 64 available sequences or available sequence templates in one cell. However, in the following embodiment 3, there are still 64 available sequences or 64 available sequence templates in one cell, which will be described in detail in the following embodiment 3.

Embodiment three:

In this embodiment, the number of available PRACH sequences or sequence templates in one cell is still kept at 64, and the UE selects and transmits the preamble sequence in a manner similar to the previous two embodiments, and will not be described in detail here.

The difference from the previous embodiment is that in this embodiment, the 6-bit RAPID parameter can no longer be used to indicate the preamble sequence used by the UE and the frequency domain position of the RB occupied by the preamble sequence in the RB set, but only Indicates the preamble used by the UE.

Specifically, after the eNodeB successfully detects the preamble sequence sent by the UE, it sends a random access response to the UE. In the random access response, the RAPID parameter is used to indicate the preamble sequence used by the UE, and the RA-RNTI parameter is used to indicate the preamble sequence used by the UE. The time and frequency domain location of the sequence. RA-RNTI=1+t_id+10*f_id, wherein, the meaning of t_id is the same as in the previous two embodiments, indicating the sequence number of the first subframe where the preamble sequence is located, 0≤t_id<10, and f_id The meaning is different from f_id in the previous two embodiments, indicating the frequency domain position of the RB set that the preamble sequence can occupy, and the frequency domain position of the RB occupied by the preamble sequence in the RB set. Specifically, the available RBs of each subframe may be numbered in ascending order of frequency in the frequency domain, and when the transmitted random access preamble sequence only occupies one RB, 0≤f_id<36.

It should be noted that, in this embodiment, any preamble sequence in the preceding two embodiments may also be used.

In addition, it should be noted that the foregoing embodiments are applicable to FDD and TDD. In FDD, only one preamble sequence or sequence template can be transmitted at a time; in TDD, a maximum of 6 preamble sequences or sequence templates can be transmitted at a time, and they are frequency division multiplexed.

It can be seen that the method for enhancing PRACH coverage provided by the embodiment of the present invention solves the problem of limited PRACH coverage in the LTE system by reducing the number of RBs used by each user's PRACH sequence and increasing the signal-to-noise ratio in the case of full power transmission. . Moreover, the random access response sent by the eNodeB to the UE indicates information such as the preamble sequence used by the UE and the time and frequency domain positions of the RBs occupied by the preamble sequence, which ensures the random access process of the UE and the cell edge User's communication quality.

As shown in FIG. 3 , it is a flow chart of implementing a contention-based random access method on the user equipment side in an embodiment of the present invention, including the following steps:

Step 301, selecting a preamble sequence in a random access process, and the frequency domain width occupied by the preamble sequence is less than 6 RBs;

Step 302, sending the preamble sequence.

As mentioned above, in practical applications, the preamble sequence may be a sequence selected by the UE from the physical random access channel PRACH sequence set for contention-based random access, and the frequency domain width occupied by the preamble sequence is 1 RB; the preamble sequence may also be a sequence template selected by the UE from a sequence template set, and the sequence template is composed of multiple PRACH sequences for contention-based random access.

To this end, the above step 301 may specifically select a sequence from a set of PRACH sequences used for contention-based random access as the preamble sequence, and the frequency domain width occupied by the preamble sequence is 1 RB. Correspondingly, the above-mentioned step 302 may specifically be: when the length of the preamble sequence is 139, sending the preamble sequence in one TTI; when the length of the preamble sequence is 839, sending the preamble sequence in multiple consecutive TTIs For the above preamble, the frequency domain positions of the RBs occupied by the part of the preamble sent in each TTI are the same. For a specific sending manner, reference may be made to the foregoing description, and details are not repeated here.

Alternatively, the above step 301 may specifically be a sequence template selected from a sequence template set, where the sequence template is composed of multiple PRACH sequences for contention-based random access. Correspondingly, the above step 302 may specifically be to sequentially transmit multiple PRACH sequences in the sequence template in multiple consecutive TTIs, and the frequency domain positions of RBs occupied by one PRACH sequence transmitted in each TTI are the same. For a specific sending manner, reference may be made to the foregoing description, and details are not repeated here.

It can be seen that the method for enhancing PRACH coverage provided by the embodiment of the present invention solves the problem of limited PRACH coverage in the LTE system by reducing the number of RBs used by each user's PRACH sequence and increasing the signal-to-noise ratio in the case of full power transmission. question.

Correspondingly, the embodiments of the present invention also provide a network device, which can implement the method for enhancing PRACH coverage in the above embodiments of the present invention. As shown in Fig. 4, it is a schematic structural diagram of the device.

In this embodiment, the device includes:

The detection unit 401 is configured to detect the preamble sent by the UE to determine the time domain and frequency domain position of the preamble; the frequency domain width occupied by the preamble is less than 6 RBs;

The sending unit 402 is configured to send a random access response on the PDSCH, where the random access response indicates the preamble used by the user equipment, and the time domain and frequency domain positions of the RBs occupied by the preamble.

Wherein, the preamble sequence is a sequence selected by the UE from a set of PRACH sequences used for contention-based random access, and the frequency domain width occupied by the preamble sequence may be 1 RB. Correspondingly, the network device further includes: a receiving unit (not shown), configured to receive the preamble sequence with a length of 139 sent by the UE within one TTI; The preamble sequence with a length of 839 is sent in a TTI, wherein the frequency domain positions of RBs occupied by part of the preamble sequences received in each TTI are the same.

The preamble sequence may also be a sequence template selected by the UE from a sequence template set, and the sequence template is composed of multiple PRACH sequences for contention-based random access. Correspondingly, the network device further includes: a receiving unit (not shown), configured to receive the PRACH sequences in the sequence template sent by the UE in multiple consecutive TTIs, and one PRACH sequence sent in each TTI The frequency domain positions of the RBs occupied by the PRACH sequences are the same. In a specific application, the preamble sequence can be of different lengths, be a PRACH sequence, or a sequence template composed of multiple PRACH sequences, and for preamble sequences of different lengths and modes, the UE adopts a corresponding transmission method, which can be specifically See previous description.

Correspondingly, for the network device in this embodiment of the present invention, the sending unit 402 can use various methods to make the random access response indicate the preamble used by the UE and the preamble The time domain and frequency domain position of the occupied RB, for example: the RA-RNTI parameter in the random access response can be used to indicate the time domain and frequency domain position of the RB set that the preamble sequence used by the UE can occupy; RA-RNTI= 1+t_id+10*f_id, where t_id indicates the sequence number of the first subframe where the preamble is located, 0≤t_id<10; f_id indicates the frequency domain position of the RB set that the preamble can occupy, 0≤ f_id<6; use the RAPID parameter in the random access response to indicate the preamble and the frequency domain position of the RB occupied by the preamble in the RB set; or use the RAPID parameter in the random access response The RAPID parameter indicates the preamble sequence; use the RA-RNTI parameter in the random access response to indicate the time domain and frequency domain positions of the RB set that the preamble sequence used by the user equipment can occupy, and the RB set occupied by the preamble sequence The frequency domain position of the RB in the RB set; RA-RNTI=1+t_id+10*f_id, where t_id indicates the sequence number of the first subframe where the preamble sequence is located, 0≤t_id<10; f_id indicates The frequency domain position of the RB set that the preamble sequence can occupy, the RB available for each subframe can be numbered in ascending order of frequency in the frequency domain, and when the random access preamble sequence that is sent only occupies one RB, 0≤f_id< 36. For the specific process, refer to the description in the method for enhancing PRACH coverage in the embodiment of the present invention above, which will not be repeated here.

It can be seen that the network equipment in the embodiment of the present invention solves the problem of limited PRACH coverage in the LTE system by reducing the number of RBs used by each user's preamble sequence and increasing the signal-to-noise ratio in the case of full power transmission to enhance coverage. Moreover, the random access response sent to the UE indicates the preamble sequence used by the UE and the time domain and frequency domain positions of the RB occupied by the preamble sequence, which ensures the random access process of the UE and the communication of the cell edge users. quality. The network device may be an eNodeB.

Correspondingly, an embodiment of the present invention also provides a user equipment, which can implement the method for enhancing PRACH coverage in the foregoing embodiments of the present invention. FIG. 5 is a schematic structural diagram of the user equipment.

In this embodiment, the user equipment includes:

The processing unit 501 is configured to select a preamble sequence during random access, where the frequency domain width occupied by the preamble sequence is less than 6 RBs;

The sending unit 502 is configured to send the preamble sequence.

As mentioned above, the preamble sequence sent by the UE can be of different lengths, be a PRACH sequence, or a sequence template composed of multiple PRACH sequences, and for preamble sequences of different lengths and patterns, the UE adopts corresponding transmission methods, For details, refer to the previous description.

Taking the frequency domain width occupied by the preamble sequence as an example, correspondingly, in a specific embodiment of the user equipment of the present invention, the processing unit 501 is specifically configured to use contention-based random access Select a sequence from the PRACH sequence set as the preamble sequence; the sending unit 502 is specifically configured to send the preamble sequence within one TTI when the length of the preamble sequence is 139; the length of the preamble sequence When it is 839, the preamble sequence is sent in multiple consecutive TTIs, and the part of the preamble sequence sent in each TTI occupies the same frequency domain position of the RB.

In a specific embodiment of the user equipment of the present invention, the processing unit 501 is specifically configured to select a sequence template from a sequence template set, and the sequence template consists of multiple PRACH sequences for contention-based random access Composition; the sending unit 502 is specifically configured to sequentially send the PRACH sequences in the sequence template in multiple consecutive TTIs, and the frequency domain positions of the RBs occupied by a PRACH sequence sent in each TTI are the same.

For PRACH sequences of different lengths or sequence templates composed of multiple PRACH sequences, the detailed process of sending them by the sending unit 502 can refer to the description in the method for enhancing PRACH coverage in the embodiment of the present invention, and will not be repeated here. .

The user equipment provided by the embodiment of the present invention uses a preamble sequence occupying a frequency domain width of less than 6 RBs, increases the signal-to-noise ratio in the case of full power transmission to enhance coverage, and solves the problem of limited PRACH coverage in the LTE system.

Each embodiment in this specification is described in a progressive manner, the same and similar parts of each embodiment can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and for relevant parts, please refer to part of the description of the method embodiment. The device embodiments described above are only illustrative, and the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in One place, or it can be distributed to multiple network elements. Part or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. It can be understood and implemented by those skilled in the art without creative effort.

The embodiments of the present invention have been described in detail above, and the present invention has been described using specific implementation methods herein. The descriptions of the above embodiments are only used to help understand the method and equipment of the present invention; meanwhile, for those of ordinary skill in the art, According to the idea of the present invention, there will be changes in the specific implementation and scope of application. To sum up, the contents of this specification should not be construed as limiting the present invention.

Claims (16)

1. A contention-based random access method, comprising: Detecting the preamble sequence sent by the user equipment UE, and determining the time domain and frequency domain position of the preamble sequence, wherein the frequency domain width occupied by the preamble sequence PRACH is less than 6 resource blocks RB; A random access response is sent on the physical downlink shared channel PDSCH, where the random access response indicates the preamble used by the UE and the time domain and frequency domain positions of the RBs occupied by the preamble. 2. The method according to claim 1, wherein the preamble sequence is a sequence selected by the UE from a physical random access channel (PRACH) sequence set for contention-based random access, and the preamble The frequency domain width occupied by the sequence is 1 RB; The method also includes: receiving the preamble sequence with a length of 139 sent by the UE within one transmission time interval TTI; or receiving the preamble sequence with a length of 839 sent by the UE in multiple consecutive TTIs, where the frequency domain positions of the RBs occupied by the part of the preamble sequences received in each TTI are the same. 3. The method according to claim 1, wherein the preamble sequence is a sequence template selected by the UE from a sequence template set, and the sequence template is composed of multiple contention-based random access PRACH sequence composition; The method also includes: The PRACH sequence in the sequence template sent by the UE in multiple consecutive TTIs is received, and the frequency domain position of the RB occupied by a PRACH sequence sent in each TTI is the same. 4. The method according to any one of claims 1 to 3, wherein the random access response indicates the preamble used by the UE and the time domain and frequency domain positions of the RBs occupied by the preamble include: Using the random access radio network temporary identifier RA-RNTI parameter in the random access response to indicate the time domain and frequency domain positions of the RB set that the preamble sequence used by the user equipment can occupy; Using the random access preamble identifier RAPID parameter in the random access response to indicate the preamble and the frequency domain position of the RB occupied by the preamble in the RB set. 5. The method according to any one of claims 1 to 3, wherein the random access response indicates the preamble used by the UE and the time domain and frequency domain positions of the RB occupied by the preamble include: using the RAPID parameter in the random access response to indicate the preamble; Use the RA-RNTI parameter in the random access response to indicate the time-frequency position of the RB set that the preamble sequence used by the user equipment may occupy, and the frequency domain position of the RB occupied by the preamble sequence in the RB set ; RA-RNTI=1+t_id+10*f_id, wherein, t_id indicates the serial number of the first subframe where the preamble sequence is located; f_id indicates the frequency domain position of the RB set that the preamble sequence can occupy, and the The frequency domain position of the RB occupied by the preamble sequence in the RB set. 6. A contention-based random access method, comprising: Selecting a preamble sequence during the random access process, the preamble sequence occupying a frequency domain width of the physical random access channel PRACH is less than 6 resource blocks RB; Send the preamble. 7. The method of claim 6, wherein, The selection of the preamble in the random access process includes: Selecting a sequence from a physical random access channel PRACH sequence set used for contention-based random access as the preamble sequence, where the frequency domain width occupied by the preamble sequence is 1 RB; The sending the preamble sequence includes: When the length of the preamble sequence is 139, the preamble sequence is sent in one transmission time interval TTI; when the length of the preamble sequence is 839, the preamble sequence is sent in multiple consecutive TTIs, each The frequency domain positions of the RBs occupied by the part of the preamble sequences sent in the TTI are the same. 8. The method of claim 6, wherein The selection of the preamble in the random access process includes: A sequence template selected from a sequence template set, the sequence template is composed of a plurality of PRACH sequences for contention-based random access; The sending the preamble sequence includes: The multiple PRACH sequences in the sequence template are sequentially transmitted in multiple consecutive TTIs, and the frequency domain positions of RBs occupied by one PRACH sequence transmitted in each TTI are the same. 9. A network device, characterized in that, comprising: The detection unit is used to detect the preamble sequence sent by the user equipment UE, and determine the time domain and frequency domain position of the preamble sequence; the frequency domain width of the physical random access channel PRACH occupied by the preamble sequence is less than 6 resource blocks RB; The sending unit is configured to send a random access response on the physical downlink shared channel PDSCH, the random access response indicates the preamble used by the user equipment, and the time domain and frequency domain positions of the RB occupied by the preamble. 10. The network device according to claim 9, wherein the preamble sequence is a sequence selected by the UE from a set of physical random access channel (PRACH) sequences used for contention-based random access, the The frequency domain width occupied by the preamble sequence is 1 RB; the network equipment also includes: a receiving unit, configured to receive the preamble sequence with a length of 139 sent by the UE in one transmission time interval TTI; or receive the preamble sequence with a length of 839 sent by the UE in multiple consecutive TTIs, Wherein, the frequency domain positions of the RBs occupied by the received partial preamble sequences in each TTI are the same. 11. The network device according to claim 9, wherein the preamble sequence is a sequence template selected by the UE from a sequence template set, and the sequence template is used by multiple contention-based random access The PRACH sequence composition; The network equipment also includes: The receiving unit is configured to receive the PRACH sequence in the sequence template sent by the UE in multiple consecutive TTIs, and the frequency domain positions of RBs occupied by a PRACH sequence sent in each TTI are the same. 12. The network device according to any one of claims 9 to 11, characterized in that, The sending unit uses the RA-RNTI parameter in the random access response to indicate the time domain and frequency domain position of the RB set that the preamble sequence used by the user equipment can occupy; uses the RAPID parameter in the random access response Indicate the preamble sequence and the frequency domain position of the RB occupied by the preamble sequence in the RB set. 13. The network device according to any one of claims 9 to 11, characterized in that, The sending unit uses the RAPID parameter in the random access response to indicate the preamble sequence; uses the RA-RNTI parameter in the random access response to indicate the time of the RB set that the preamble sequence used by the user equipment can occupy domain and frequency domain positions, and the frequency domain position of the RB occupied by the preamble sequence in the RB set; RA-RNTI=1+t_id+10*f_id, where t_id indicates the first RB where the preamble sequence is located The serial number of the subframe; f_id indicates the frequency domain position of the RB set that the preamble sequence may occupy, and the frequency domain position of the RB occupied by the preamble sequence in the RB set. 14. A user equipment, characterized in that it comprises: The processing unit is used to select a preamble sequence during the random access process, and the preamble sequence occupies a frequency domain width of the physical random access channel PRACH less than 6 resource blocks RB; A sending unit, configured to send the preamble sequence. 15. The user equipment according to claim 14, characterized in that, The processing unit is specifically configured to select a sequence from a physical random access channel PRACH sequence set used for contention-based random access as the preamble sequence, and the frequency domain width occupied by the preamble sequence is 1 RB; The sending unit is specifically configured to send the preamble sequence within one transmission time interval TTI when the length of the preamble sequence is 139; when the length of the preamble sequence is 839, within multiple consecutive TTIs The preamble sequence is sent, and the frequency domain positions of the RBs occupied by the part of the preamble sequence sent in each TTI are the same. 16. The user equipment according to claim 14, characterized in that, The processing unit is specifically used to select a sequence template from a sequence template set, and the sequence template is composed of a plurality of PRACH sequences for contention-based random access; The sending unit is specifically configured to sequentially send a plurality of PRACH sequences in the sequence template in a plurality of consecutive TTIs, and a frequency domain position of an RB occupied by a PRACH sequence sent in each TTI is the same.