WO2009021405A1

WO2009021405A1 - Method, system and apparatus for tdd random access

Info

Publication number: WO2009021405A1
Application number: PCT/CN2008/001461
Authority: WO
Inventors: Hai Tang; Shiqiang Suo; Libo Wang
Original assignee: Datang Mobile Communications Equipment Co., Ltd.
Priority date: 2007-08-13
Filing date: 2008-08-13
Publication date: 2009-02-19
Also published as: CN101369840A; CN101369840B

Abstract

The invention relates to an assignment method for random access channel of medium-scale and large-scale systems in TD-SCDMA evolution system, and the preamble sequence can be assigned to the uplink slots far apart from the GP by appending guard period to the random access preamble sequence when the interference is large. The invention can solve the technical problem that the TS0 and DwPTS timeslots of the remote cells produce interference to the random access preamble sequence of the current cell. The assignment of the random access channel becomes more flexible and the detection success probability of the preamble sequence by the base station is improved by application of the invention.

Description

Time division duplex random access method, system and device thereof

Technical field

The present invention relates to the field of mobile communication technologies, and in particular, to an Orthogonal Frequency Division Multiplexing (OFDM) based Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) evolution system. The random access technology, more particularly relates to a time division duplex random access method, system and device thereof for medium coverage and large coverage systems. Background technique

TD-SCDMA is the only three-dimensional international standard for third-generation mobile communication systems that adopts Time Division Duplex (TDD), which supports international standards for uplink and downlink asymmetric service transmission, and has greater flexibility in spectrum utilization. The system uses advanced technologies in wireless communication such as smart antenna, uplink synchronization, joint detection and software radio to make the system have higher performance and spectrum utilization. With the development of society and the advancement of technology, people's requirements for mobile communication are also increasing. It is hoped that the system can provide high-capacity, high-rate, low-latency data transmission services. To meet this growing demand, TD-SCDMA systems also need to evolve and improve performance.

In the evolution scheme of TD-SCDMA, in order to obtain a high-speed and large-capacity service, it is required to occupy a wider bandwidth, so it is called a broadband time division duplex cellular system. In a broadband time division duplex cellular system, the radius of the cell to be covered can be divided into three levels, namely 5 km, 30 km and 100 km. For a 100km system, it is usually called a large coverage system, a 30km system is called a medium coverage system, and a 5km system is called a small coverage system.

The asynchronous random access preamble sequence of the broadband time division duplex cellular system is used for uplink clock synchronization and UE identifier detection. In a broadband time division duplex cellular system designed for medium coverage and large coverage, the preamble sequence is immediately adjacent to the uplink and downlink transition point, and the uplink and downlink transition time at this time corresponds to the uplink and downlink protection of the cell radius, so the signal of the neighboring cell base station It is likely to interfere with the random access preamble sequence of the cell. In practice, the data slot of the cell after the uplink and downlink guard interval may also be interfered, but for the data channel, interference to the data channel may be avoided by scheduling or using other interference avoidance or cancellation methods. Even if there is a block demodulation error Mistakes can also be guaranteed by retransmission. However, for a random access channel, the impact of large interference on the user UE (terminal) is very large, which reduces the access success rate of the UE, and prolongs the random access time of the UE, and affects the specific use of the user. Very big.

1( a ) is a frame structure of an original TD-SCDMA evolved system in a prior art broadband time division duplex cellular system, and FIG. 1 ( b ) is a frame structure in a large coverage case of a prior art broadband time division duplex cellular system. In the figure, the time slot TS0 is fixed as a downlink time slot, the DwPTS is a downlink pilot time slot, the GP is an uplink and downlink guard interval, and the UpPTS is an uplink pilot time slot. In the figure, the indication marked with † is the uplink time slot, the indication marked with 丄 is the downlink time slot, and the dotted line between TS4 and TS6 or TSx indicates the omitting, and the intermediate time slot is not shown. In the large coverage system, TSx represents the Xth time slot. Since it is an uplink or downlink time slot, the uplink and downlink attributes are not marked in the figure. In the large coverage system, the 接入4 machine access channel occupies resources in the frequency domain and cannot be represented by the UpPTS time slot as in the small coverage system. Therefore, in the large coverage system of Figure 1 (b), the previous synchronization The code sequence is used to identify.

In Figure 1 (b), the random access preamble sequence is allocated next to the GP, wherein the length of the GP corresponds to twice the radius of the cell, that is, the time elapsed by the photospeed corresponding to the cell radius distance of 2 times. In the case of medium coverage and large coverage, in order to meet the requirement of receiving signal to noise ratio of the base station, the preamble sequence needs to be extended accordingly. In the case of medium coverage and large coverage, when the UE of the local cell sends a random access preamble sequence to the base station of the local cell, the random access preamble sequence arrives at the local cell together with the TS0 time slot or the DwPTS time slot signal of the remote cell. The base station, that is, the random access preamble sequence of the local cell is interfered by the TS0 time slot and the DwPTS time slot signal of the remote cell, for example, the first layer cell outside the local cell. In fact, the uplink data slots of the UE in the cell, such as TS2 and TS3, are also interfered by the remote cell TS0 slot and the DwPTS slot, but because the data is transmitted, the specific data transmission can pass through the base station. To perform scheduling, or to use interference coordination, or to use interference avoidance, to reduce the impact of the remote cell on the uplink data slot of the local cell. Even if the data block in the case of interference, a detection error occurs, the correct transmission can be ensured by retransmission.

However, the remote cell TS0 time slot and DwPTS time slot signal interference have a great influence on the preamble sequence. These interferences can reduce the reception quality of the preamble sequence by the base station of the cell, and the success rate of the random access detection is reduced. After the UE sends the preamble sequence for random access, it will perform reception detection on the corresponding channel during the feedback time of the waiting base station to see if there is any access back from the base station. Successful instructions. However, due to the existence of interference, the performance of the base station detecting the preamble sequence is degraded, so that the preamble sequence cannot be correctly detected. If the base station cannot correctly detect the preamble sequence, the base station does not send feedback information to the UE. If the UE does not detect the feedback signal on the corresponding feedback channel, the UE will wait until the preset waiting time expires, and the UE will re-initiate another random access. Due to the last random access detection, many UEs do not receive the correct feedback information, so more UEs will send a preamble sequence to the base station at the next moment, causing the base station to detect the performance of multiple preamble sequences. Further decline.

In summary, the interference of the TS0 time slot and the DwPTS time slot of the remote cell has a large impact on the random access process, which in turn affects the normal operation of the entire communication system. Summary of the invention

In view of this, one of the objects of the present invention is to solve the technical problem of the interference of the downlink time slot of the remote cell to the random access preamble.

In order to achieve the above object, an aspect of the present invention provides a time division duplex random access method, including the following steps: a base station broadcasts location information of a random access channel and an optional preamble sequence through a broadcast channel, where The length of the random access channel is greater than the length of the preamble sequence; the base station receives the preamble sequence selected by the UE sent by the terminal UE through the random access channel, and the random access channel includes at least a blank area, as a guard interval of the preamble sequence selected by the UE; the base station performs random access detection on the UE according to the preamble sequence sent by the UE.

As an embodiment of the present invention, the location information of the random access channel is determined by: configuring a length of the random access channel according to a coverage of the base station and a length of an optional preamble sequence, The length of the random access channel is an integer multiple of the length of the uplink time slot; determining the location of the random access channel according to the uplink time slot scheduled by the base station and the length of the random access channel, so that the random access The access channel is located in an uplink time slot that is far from the uplink and downlink guard interval.

In the above embodiment, the guard interval is located after the preamble sequence, immediately adjacent to the preamble sequence.

In the above embodiment, the sum of the guard interval, the preamble sequence, and the length of the cyclic prefix is equal to the length of the random access channel. In the above embodiment, the guard interval length ranges from greater than zero to less than or equal to 2 times the speed of light corresponding to the cell radius distance.

In the above embodiment, before the base station broadcasts the location information of the random access channel and the selectable preamble sequence through the broadcast channel, the method further includes: grouping the preamble sequence according to the channel transmission quality. And the UE selects the preamble sequence after the group according to the current downlink channel quality.

In the above embodiment, the random access preamble sequence is a directly generated long synchronization code sequence, or is formed by repeating a short synchronization code sequence.

In the above embodiment, the synchronization code sequence is a Zadoff-Chu sequence, a GCL sequence, a Golay sequence or a Barker sequence.

Another aspect of the present invention further provides a time division duplex random access method, comprising the steps of: receiving, by a UE, location information of a random access channel broadcast by a base station and an optional preamble sequence, where the random access channel The length is greater than the length of the preamble sequence; the UE randomly selects a preamble sequence in the selectable preamble sequence to send to the base station through a random access channel, the random access The channel includes at least one blank area as a guard interval of the preamble sequence selected by the UE. The UE detects the response channel of the base station, and obtains a result of the base station detecting the random access of the UE.

In the above embodiment, the guard interval is located after the preamble sequence, immediately adjacent to the preamble sequence, and the sum of the guard interval, the preamble sequence, and the length of the cyclic prefix is equal to the The length of the random access channel.

In the above embodiment, the guard interval length ranges from greater than zero to less than or equal to 2 times the distance traveled by the aperture distance.

In the above embodiment, the UE randomly selects one preamble sequence in the optional preamble sequence, where the UE is: according to the current downlink channel quality, the preamble sequence. Column to make a selection.

A further aspect of the present invention further provides a random access channel, where the length of the random access channel is greater than the length of the preamble sequence, and the random access channel includes at least one blank area as a UE to the base station. The guard interval of the transmitted preamble sequence.

As an embodiment of the present invention, the length of the random access channel is an integer multiple of the length of the uplink time slot.

As an embodiment of the present invention, the guard interval is located after the preamble sequence, immediately adjacent to the preamble sequence, and the sum of the guard interval, the preamble sequence, and the length of the cyclic prefix is equal to The length of the random access channel.

In the above embodiment, the guard interval length ranges from greater than zero to less than or equal to the time elapsed for the optical speed corresponding to the cell radius distance.

A further aspect of the present invention further provides a UE, comprising: a sequence selection module, configured to select a preamble sequence in the base station broadcast information; and a random access channel forming module, configured to use the broadcast information and the selected The preamble sequence forms a random access channel; the sending module is configured to send the preamble sequence to the base station of the cell by using a random access channel, where the random access channel further includes a blank area as the preamble sequence The protection interval of the base station is used to detect the response channel of the base station to determine whether the access is successful.

As an embodiment of the present invention, the preamble sequence and the guard interval are located in an uplink slot that is away from the uplink and downlink guard interval.

A further aspect of the present invention provides a base station, including: a broadcast module, configured to broadcast location information of a random access channel and a preamble sequence usable by the current cell through a broadcast channel; and a random access sequence detecting module, And a preamble sequence for detecting a random access channel, where the random access channel further includes a blank area as a guard interval of the preamble sequence; a random access response mode a block, configured to respond to the detected preamble sequence by a response channel.

As an embodiment of the present invention, an uplink time slot setting module is further configured to configure an uplink time slot according to a coverage area and a time slot width occupied by the preamble sequence and the guard interval.

As an embodiment of the present invention, a preamble sequence grouping module is further included for grouping according to a grouping condition corresponding to each preamble sequence.

The present invention also provides a time division duplex random access system, comprising: a base station and at least one UE served by the base station, the base station comprising: a broadcast module, configured to use location information of the random access channel and the local cell to be used The preamble sequence is broadcasted through a broadcast channel; a random access sequence detection module is configured to detect a preamble sequence sent by the UE in the random access channel; and a random access response module is configured to detect the preamble through the response channel pair The synchronization code sequence is responsive; the UE includes: a sequence selection module, configured to select a preamble sequence in the base station broadcast information, and a random access channel formation module, configured to use the broadcast information and the selected preamble The code sequence forms a random access channel; the sending module is configured to send the preamble sequence to the cell base station by using a random access channel, where the random access channel further includes a blank area as a guard interval of the preamble sequence a base station response detecting module, configured to detect, according to a response channel of the base station, whether the access is successful

As an embodiment of the present invention, the preamble sequence and the guard interval are located in an uplink slot that is away from the uplink and downlink guard interval. The present invention is directed to a broadband time division duplex cellular system. In the case of medium coverage and large coverage, the proposed random access channel design scheme with guard interval does not require the preamble sequence to be close to the uplink and downlink protection interval, so that the random access channel is The allocation is more flexible. The present invention places the preamble sequence with the guard interval as far as possible from the uplink time slot position of the uplink and downlink guard interval, so that the interference of the remote base station can be avoided as much as possible according to the allocation criterion of the random access channel, and the base station of the base station is guaranteed. Correct detection of the random access channel can achieve accurate and fast random access of the UE, and provides an effective solution for the OFDM system to achieve random access of the UE. DRAWINGS

1(a) is a design diagram of a frame structure of a prior art original TD-SCDMA evolution system and a random access UpPTS;

1(b) is a frame structure of a prior art TD-SCDMA evolution system in a case of large coverage; FIG. 2 is a Preamble sequence structure following a guard interval according to an embodiment of the present invention; 8 001461 FIG. 3 ( a ) is a diagram of a random access channel location allocation in a case of a small coverage of 5 km according to an embodiment of the present invention;

FIG. 3(b) is a diagram showing a random access channel position allocation in a case of coverage of 30 km according to an embodiment of the present invention;

FIG. 3(c) is a diagram showing a location allocation of a random access channel in a case of a large coverage of 100 km according to an embodiment of the present invention;

4(a) is a diagram showing a random access channel location allocation in the case where TS4 is a small coverage of 5 km downlink time slot according to an embodiment of the present invention;

4(b) is a diagram showing a random access channel location allocation in the case where the TS4 is a coverage of a downlink time slot of 30 km according to an embodiment of the present invention;

4(c) is a diagram showing a random access channel location allocation diagram in the case where TS4 is a 100 mL large coverage of a downlink time slot according to an embodiment of the present invention;

FIG. 5 is a sequence diagram of a random access procedure between a UE and a base station according to an embodiment of the present invention;

FIG. 6 is a block diagram of a random access part of a UE and a base station according to an embodiment of the present invention. detailed description

The main idea of the present invention is to redesign the random access channel structure, and in the case that uplink channel allocation is possible, the redesigned random access channel can be flexibly configured in the uplink channel, and the cell is randomly connected. The sending position of the preamble sequence is far away from the time when the TS0 time slot and the DwPTS time slot of the remote base station reach the local cell, and the interference of the downlink time slot of the remote base station to the preamble sequence of the current cell is reduced as much as possible, thereby improving the detection of the random access channel. Success rate and access speed of the UE.

As an embodiment of the present invention, the present invention includes a blank area in the random access channel that does not transmit any data, and the guard interval (GT) as a preamble sequence in the blank area is used to eliminate the time due to the preamble sequence. The interference caused by the uncertainty to the data slots before and after, as shown in Figure 2. Of course, as a preferred solution of the present invention, a guard interval is set in the random access channel, but those skilled in the art should understand that setting multiple guard intervals, such as setting a protection before and after. Intervals, as well as the objects of the invention, are also encompassed by the scope of the invention. As a preferred embodiment of the present invention, the sum of the guard interval GT, the preamble sequence, and the cyclic prefix CP is equal to the length of the random access channel. With the improved random access channel allocation structure, the random access channel is not necessarily limited to the GP to allocate, because the preamble sequence in the random access channel allocation structure has its own guard interval, which can avoid the preamble sequence forward. Or when moving backwards, it interferes with the data slots before and after. The range of values of the GT is theoretically greater than zero, and is less than or equal to the time required for the speed of light to travel twice the radius of the cell. As an embodiment of the present invention, the value of the GT in the present invention is configurable, and in the case that the base station receives the signal to noise ratio, the base station antenna coverage distance may be determined by the base station antenna. In general, the UE estimates a timing advance when transmitting the preamble sequence such that the preamble sequence it transmits can reach the base station at its target time. As shown in Figure 3 (b), the target moment of the preamble sequence should be at the beginning of the TS3 slot. If a UE is at the cell edge, the UE needs to advance GT/2 time when transmitting the preamble sequence, which sends the preamble sequence. The cell base station will arrive at the start position of the TS3 slot, so that the preamble sequence will not affect the data slots before and after due to the guard interval.

Comparing Fig. 1(b) with Fig. 3(b) and Fig. 3(c), it can be seen that in the allocation structure of the random access channel of the existing medium coverage and large coverage systems, the preamble sequence can only be assigned tightly. The location of the GP, and in the case where uplink channel allocation is possible, the Preamble sequence structure with guard interval shown in FIG. 2 is used, and the specific location transmitted in the random access channel is no longer limited to the GP. In the first time slot, it can be flexibly configured in the uplink channel scheduled by the base station. As an embodiment of the present invention, the Preamble sequence can be placed as far as possible from the GP, which needs to be specifically set according to the number and location of uplink time slots scheduled by the base station, such as placing the random access preamble sequence in TS3 and The TS4 slot position, or the random access preamble sequence can be placed in the TS5 and TS6 slot positions, or even further slot positions. In addition, the Preamble sequence can occupy more than two time slots, and the number of specific occupied slots will be described in detail in the following description. Therefore, it can be seen that the setting of the random access channel is different due to the specific conditions of the uplink time slot scheduled by the base station, and the structure of the random access channel may have multiple modes. The following random access channels of the present invention are shown in FIG. 3 and FIG. The examples are only for the purpose of facilitating the understanding of the present invention, and it is not intended that the present invention can be realized only by the examples described below.

In the large coverage system shown in Figure 3 (c), when the interference is relatively large, when TS3 and TS4 are also uplink time slots, the random access preamble sequence can be placed in the TS3 and TS4 time slot positions. will The preamble sequence is placed at the TS3 and TS4 slot positions, so that the transmission position of the random access preamble sequence is far away from the time when the remote base station TS0 slot and the DwPTS slot reach the local cell, thereby avoiding the remote base station TS0 slot and DwPTS slot. Interference with the preamble sequence of the cell.

Figure 4) and Figure 4 (c) show the comparison of the location allocation scheme of the random access preamble sequence with the small coverage and large coverage, TS4 is the downlink time slot, and Figure 4 (b) shows the medium coverage. TS3 is a random access preamble sequence location allocation scheme for downlink time slots. In the case of medium coverage, since TS3 is downlink, the random access preamble sequence can only be allocated in the TS1 and TS2 slot positions. In the case of large coverage, since TS4 is downlink, the random access preamble sequence can only be allocated in the TS2 and TS3 slot positions. Compared with the GT-free scheme, in the random access channel allocation scheme, the preamble sequence does not occupy the GP time, and the interference of the remote base stations TS0 and DwPTS is small. In practice, this structure can be mainly applied to cells in which TS0 and DwPTS interference is not very large.

With the random access preamble sequence structure with guard interval designed by the present invention, the allocation criterion in the random access channel of the medium coverage and the large coverage system is: when there is enough uplink channel, according to the interference situation Random access preamble sequence location allocation. When the interference is relatively large, the random access preamble sequence and its guard interval are allocated as far as possible to the uplink time slot position away from the uplink and downlink guard interval. Thus, in the case where there are enough uplink time slots, the interference of the remote base station can be avoided.

As an embodiment of the present invention, the interference of the TS0 and the DwPTS of a specific cell may be measured when the cell is initially set, and the random access channel may be allocated according to the measured value, without dynamic measurement, and dynamic measurement It is also complicated and difficult to measure.

The lengths of the random access preamble sequences with guard intervals given in FIG. 3 and FIG. 4 are both corresponding to the length of two time slots. However, in practice, in order to ensure the detection probability, the random access preamble sequence and the GT may be longer, It is the length of N time slots. which is

Length ( preamble serial number 'J + GT ) = NxLength ( TS )

Length represents a function of the length of time. For medium coverage, N is an integer greater than or equal to 1, that is, the length of the preamble and GT can be placed in one time slot. For large coverage, N can only be taken. An integer greater than 1, because only one time slot is used for preamble transmission is not sufficient for large coverage. The meaning of the above formula is: preamble sequence and GT protection The sum of the occupied durations of the intervals is equal to an integer multiple of one slot in TD-SCDMA.

In the case that the interference is relatively strong, the allocation criterion of the random access preamble sequence with guard interval according to the present invention in the random access channel is applicable to the random access preamble sequence of any length.

As an embodiment of the present invention, in the specific embodiment of the present invention, the following method may be used to generate a long preamble sequence of a large-area cell:

A. Directly generate a long preamble sequence. The advantage of this method is that the number of sequences that can be used is large, but the complexity of generating long preamble sequences is relatively high, and implementation is difficult;

B. The shorter length preamble sequence is repeated to form a long preamble sequence. The advantage of this method is that while providing a sufficient number of sequences, it can avoid the high complexity of directly generating long sequences, and can improve the detection performance to some extent.

As an embodiment of the present invention, the selection of a specific preamble sequence in the present invention may select a Zadoff-Chu sequence, a GCL sequence, a Golay sequence, or a Barker sequence having good autocorrelation and cross-correlation properties.

FIG. 5 is a timing sequence diagram of a random access procedure between a UE and a base station. According to the time sequence of signal transmission, the entire random access procedure can be divided into four steps, which are described in detail below:

Step 1: The base station broadcasts the location information of the random access channel and all preamble sequence identifiers that can be used by the cell through the broadcast channel.

Due to the limitation of the random access channel length, the number of uplink time slots allocated by the base station is also limited. Different from the prior art, with the technical solution disclosed by the present invention, the number of uplink time slots at this time needs to meet the requirement of sending a random access channel length. For medium coverage, the base station must allocate at least one uplink time slot. If the random access channel occupies the length of two uplink time slots, then the base station needs to allocate at least two uplink time slots; for large coverage, the base station at least Two uplink time slots are to be allocated, otherwise the random access channel cannot be allocated. After allocating the number of uplink time slots according to the length of the random access channel and the uplink data volume requirement of the system, the base station allocates the number of random access channels according to the estimated number of initiated random access users in the current cell. After determining the length of the random access channel, the location of the random access channel may be determined according to the uplink time slot and the length of the random access channel scheduled by the base station, so that the random access channel is located in an uplink time slot that is far away from the uplink and downlink protection interval. in. As shown in FIG. 3, the length of the random access channel can be set to two TSs, and when the TS4 is an uplink time slot, the random access channel is set on TS3 and TS4; and in FIG. 4, the same random access channel is used. The length is set to two TSs, However, since TS4 is a downlink time slot, only random access channels can be set on TS2 and TS3. Of course, this is only for the convenience of understanding the case. The setting of the random access channel may be different according to the scheduling of the base station. However, according to the main idea of the present invention, the protection interval in the random access channel should be protected by the invention. Covered by the scope. Finally, the base station broadcasts the location information of the random access channel and the preamble sequence used by the local cell through the broadcast channel.

In TD-SCDMA, the number of preamble sequences that can be used by a cell is planned in the cell planning. If the number of planning is 16, the cell base station broadcasts all available preamble sequences when broadcasting downwards. The UE randomly chooses itself.

In a specific embodiment of the present invention, in order to identify the channel transmission quality corresponding to the preamble sequence to the UE, all available preamble sequences are grouped, for example, 16 sequences are divided into two groups, namely, group 1 and group 2, then select The sequence in packet 1 implies that the downlink channel quality is better; if the selected sequence is located in packet 2, the downlink channel quality is implied. The conditions for grouping may include other parameters in addition to the downlink channel quality described above.

Step 2: randomly select a preamble sequence from all preamble sequences, and send the selected preamble sequence to the base station on the random access channel according to the location information of the random access channel provided by the base station.

The UE randomly selects a preamble sequence from the optional preamble sequence group according to the broadcast information of the base station according to the current implicit information transmitted by the preamble sequence, and then arbitrarily selects one channel among all the random access channels, and sends the Preamble sequence.

The transmission timing advance of this preamble is determined according to the timing advance algorithm. Since the GT is placed after the preamble, it is necessary to subtract a constant from the time advance, ie GT/2, so that the preamble can be within the random access channel range without disturbing the data slots before and after.

Step 3: The base station performs preamble sequence detection on the allocated random access channel location. The detection is correlation detection, and the base station responds to the detected preamble sequence, and the response channel is a fixed channel. The response information of the base station includes the preamble sequence of the response, the timing advance information, and the like, and may also include resource allocation information corresponding to the preamble sequence. Of course, the resource allocation information may also be default, that is, not sent.

Step 4: The UE detects the base station response channel within a fixed length of time, if When the preamble sequence sent by itself is detected, the UE considers that it has been detected by the base station. Then, the UE sends data on the uplink resource corresponding to the preamble.

6 is a structural diagram of a time division duplex random access system according to an embodiment of the present invention, the system including a base station and at least one UE served by the base station.

As an embodiment of the present invention, the base station includes: a broadcast module, a random access sequence detection module, a random access response module, an uplink time slot setting module, and a preamble sequence grouping module. And a broadcast module, configured to broadcast the location information of the random access channel and the preamble sequence usable by the local cell through the broadcast channel. The random access sequence detecting module is configured to detect a preamble sequence in the random access channel, where the preamble sequence carries its own guard interval. The random access response module is configured to respond to the detected preamble sequence through the response channel. An uplink time slot setting module, configured to configure an uplink time slot according to a coverage area and a time slot width occupied by the preamble sequence and the guard interval, wherein the purpose of the module is that the number of uplink time slots must meet the length of the random access channel. The requirements can be set at system initialization. The preamble sequence grouping module is configured to group the preamble sequence according to a packet condition corresponding to each preamble sequence, a channel quality, and the like. The packet itself identifies information about the packet conditions to the client, and the client can perform the appropriate action based on the implicit information contained in the packet.

As an embodiment of the present invention, the UE includes: a sequence selection module, a random access channel forming module, a sending module, and a base station response detecting module. A sequence selection module is configured to select a preamble sequence in the base station broadcast information. a random access channel forming module, configured to form a random access channel according to the cell broadcast information and the selected preamble sequence, where the preamble sequence in the formed random access channel carries its own guard interval, and the preamble sequence And its guard interval is located at the location of the upstream slot in the TD-SCDMA frame. And a sending module, configured to send the preamble sequence to the cell base station by using a random access channel. The base station response detecting module is configured to detect the base station response channel to determine whether the access is successful.

The invention improves the structure of the random access channel, and in combination with the allocation criterion of the random access channel disclosed by the present invention, the interference of the remote cell TS0 time slot and the DwPTS time slot to the random access process can be avoided as much as possible. The impact of the UE, thus achieving accurate and fast random access of the UE, improves the operational efficiency of the entire communication system.

The invention may be embodied in a variety of other embodiments without departing from the spirit and scope of the invention. A person skilled in the art can make various corresponding changes and modifications in accordance with the present invention, but these respective changes and modifications are intended to fall within the scope of the appended claims.

Claims

Claim

A time division duplex random access method, characterized in that the method comprises the following steps:

The base station broadcasts the location information of the random access channel and the selectable preamble sequence through a broadcast channel, where the length of the random access channel is greater than the length of the preamble sequence;

The base station receives a preamble sequence selected by the UE that is sent by the UE by using the random access channel, and the random access channel includes at least one blank area, which is used as protection of the preamble sequence selected by the UE. Interval

The base station performs random access detection on the UE according to a preamble sequence sent by the UE.

The time division duplex random access method according to claim 1, wherein the location information of the random access channel is determined by the following steps:

And configuring a length of the random access channel according to a coverage of the base station and a length of an optional preamble sequence, where a length of the random access channel is an integer multiple of an uplink time slot length;

And determining, according to the uplink time slot scheduled by the base station and the length of the random access channel, the location of the random access channel, so that the random access channel is located in an uplink time slot that is far away from the uplink and downlink guard interval.

The time division duplex random access method according to claim 1 or 2, wherein the guard interval is located after the preamble sequence and is immediately adjacent to the preamble sequence.

The time division duplex random access method according to claim 3, wherein the sum of the guard interval, the length of the preamble sequence and the cyclic prefix is equal to the length of the random access channel.

The time division duplex random access method according to claim 4, wherein the guard interval length ranges from greater than zero to less than or equal to 2 times the speed of light corresponding to the cell radius distance.

The time division duplex random access method according to claim 4, further comprising: before the base station broadcasts the location information of the random access channel and the selectable preamble sequence through the broadcast channel, :

The preamble sequence is grouped according to channel transmission quality, and the UE selects the grouped preamble sequence according to current downlink channel quality.

The time division duplex random access method according to claim 1, wherein the random access preamble sequence is a directly generated long synchronization code sequence, or is formed by repeating a short synchronization code sequence.

The time division duplex random access method according to claim 1, wherein the synchronization code sequence is a Zadoff-Chu sequence, a GCL sequence, a Golay sequence or a Barker sequence.

9. A time division duplex random access method, comprising: the following steps:

Receiving, by the UE, location information of the random access channel broadcast by the base station and an optional preamble sequence, where a length of the random access channel is greater than a length of the preamble sequence;

The UE randomly selects one preamble sequence in the optional preamble sequence to send to the base station by using a random access channel, where the random access channel includes at least one blank area as the UE. The guard interval of the selected preamble sequence;

The UE detects a response channel of the base station, and obtains a result of the base station detecting the random access of the UE.

10. The time division duplex random access method according to claim 9, wherein the location information of the random access channel is determined by the following steps:

The time division duplex random access method according to claim 9 or 10, wherein the guard interval is located after the preamble sequence, immediately adjacent to the preamble sequence, and the guard interval, The sum of the lengths of the preamble sequence and the cyclic prefix is equal to the length of the random access channel.

The time division duplex random access method according to claim 11, wherein the guard interval length ranges from greater than zero to less than or equal to 2 times the speed of light corresponding to the cell radius distance.

The time division duplex random access method according to claim 9, wherein the UE randomly selects a preamble sequence in the selectable preamble sequence as follows:

The UE selects the preamble sequence of the packet according to the current downlink channel quality.

The time division duplex random access method according to claim 9, wherein the random access preamble sequence is a directly generated long synchronization code sequence, or is formed by repeating a short synchronization code sequence.

The time division duplex random access method according to claim 9, wherein the synchronization code The sequence is a Zadoff-Chu sequence, a GCL sequence, a Golay sequence or a Barker sequence.

A random access channel, wherein the length of the random access channel is greater than the length of the preamble sequence carried by the random access channel, and the random access channel includes at least one blank area, and the UE sends the base station to the base station. The guard interval of the preamble sequence.

The random access channel according to claim 16, wherein the length of the random access channel is an integer multiple of the length of the uplink time slot.

The random access channel according to claim 16, wherein the guard interval is located after the preamble sequence, immediately adjacent to the preamble sequence, the guard interval and the preamble sequence The sum of the lengths is equal to the length of the random access channel.

The random access channel according to claim 18, wherein the guard interval time length ranges from greater than zero to less than or equal to 2 times the speed of light corresponding to the cell radius distance.

20. A UE, comprising:

a sequence selection module, configured to select a preamble sequence in the base station broadcast information;

a random access channel forming module, configured to form a random access channel according to the broadcast information and the selected preamble sequence;

a sending module, configured to send a preamble sequence to a base station of a cell by using a random access channel, where the random access channel further includes a blank area as a guard interval of the preamble sequence; The base station response channel is detected to determine whether the access is successful.

The UE according to claim 20, wherein the preamble sequence and the guard interval are located in an uplink slot that is away from the uplink and downlink guard interval.

The UE according to claim 20, wherein the length of the random access channel is an integer multiple of the length of the uplink time slot.

A base station, comprising:

a broadcast module, configured to broadcast the location information of the random access channel and the preamble sequence usable by the local cell by using a broadcast channel, where a length of the random access channel is greater than a length of the preamble sequence;

a random access sequence detecting module, configured to detect a preamble sequence in a random access channel, where the random access channel further includes a blank area as a guard interval of the preamble sequence;

And a random access response module, configured to respond to the detected preamble sequence by using a response channel.

The base station according to claim 23, further comprising an uplink time slot setting module, configured to configure an uplink time slot according to the coverage area and the time slot width occupied by the preamble sequence and the guard interval.

The base station according to claim 24, further comprising a preamble sequence grouping module, configured to perform grouping according to a grouping condition corresponding to each preamble sequence.

26. A time division duplex random access system, comprising: a base station and at least one UE served by the base station,

The base station includes:

a random access sequence detecting module, configured to detect a preamble sequence sent by the UE in the random access channel;

a random access response module, configured to respond to the detected preamble sequence by using a response channel; the UE includes:

a sending module, configured to send a preamble sequence to the cell base station by using a random access channel, where the random access channel further includes a blank area as a guard interval of the preamble sequence;

The base station response detecting module is configured to detect, according to the base station response channel, whether the access is successful.

The time division duplex random access system according to claim 26, wherein the preamble sequence and the guard interval are located in an uplink slot that is away from the uplink and downlink guard interval.