Transmitting method and apparatus for random access leader sequence
A technology of random access preamble and transmission method, applied in the field of communication systems, can solve the problems of small number of sequences, small sequence range, narrow coverage, etc., and achieve the effect of easy implementation and simple operation
Active Publication Date: 2012-08-08
DATANG MOBILE COMM EQUIP CO LTD
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Problems solved by technology
[0017] One problem is that the coverage area will be reduced, because the time-accumulated power of the sequence with a short time length is relatively small, resulting in a reduction in the coverage area;
[0018] Another problem is that short-length sequences lead to a relatively small number of sequences that can be used, which in turn leads to a relatively small range of sequences that can be selected by the UE, which increases the collision probability of UE random access and reduces the success rate of UE random access.
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[0058] To realize that when the ratio of downlink and uplink time slots in TD-SCDMA system is 4:3, there are many ways to increase the length of UpPTS in TDD system, but these methods will cause the difference between the two systems of TD-SCDMA and TDD. conflict between.
[0059] In the prior art, when the ratio of downlink and uplink time slots in the TD-SCDMA system is 4:3, the TDD system will set its own ratio of downlink and uplink time slots to 4:4, for example figure 2 shown.
[0060] by right figure 2 From the analysis of , it can be seen that if the TDD system reduces its uplink time slot by one, the length of the UpPTS can be increased, such as image 3 shown. At this time, the ratio of downlink and uplink time slots becomes 5:3 accordingly.
[0061] From the above analysis, it can be seen that in order to increase the length of the UpPTS when the ratio of downlink and uplink time slots in the TD-SCDMA system is 4:3 under the premise of ensuring that the two sy...
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The invention discloses a method for transmitting a random access leading sequence. The method comprises the following steps: a proportion of a down link time slot and an up link time slot adopted by a TD-SCDMA system is obtained; when the proportion of the down link time slot and the up link time slot is 4 to 3, a proportion of a down link time slot and an up link time slot of a TDD system is set to 5 to 3; the random access leading sequence with a length of N OFDM symbols is configured and transmitted in UpPTS, wherein N is less than or equal to 4 and more than or equal to M, M is the length of UpPTS with OFDM symbols as a unit. The invention achieves the aim of increasing the length of the UpPTS by changing the proportion of the down link time slot and the up link time slot in the TDD system. The transmittable length of the random access leading sequence can be increased by increasing the length of the UpPTS, thereby expanding the coverage range, reducing the impact probability of UE random access, and improving the success ratio of the UE random access. Furthermore, simple operation and easy realization are outstanding advantages of the invention. The invention also discloses a device for transmitting the random access leading sequence.
Description
technical field [0001] The present invention relates to a communication system, in particular to a method and device for sending a random access preamble sequence in a Time Division Duplex (TDD) system. Background technique [0002] The current Long Term Evolution (LTE, Long Term Evaluation) solution includes two duplex multiplexing modes of Frequency Division Duplex (FDD) and TDD. The TDD system adopts a frame structure similar to that of the Time Division Synchronous Code Division Multiple Access (TD-SCDMA) system. [0003] In the TD-SCDMA system, a subframe has a length of 5 milliseconds (ms), including 7 ordinary time slots (TS0~TS6) and 3 UpPTS, downlink pilot time slot (DwPTS), and guard interval (GP). a special time slot. In the TDD system, the length of a subframe is also 5ms, including 8 common time slots and 3 special time slots, UpPTS, DwPTS, and GP. [0004] In the TD-SCDMA system, the length of an ordinary time slot is 0.675ms, and the total length of three s...
Claims
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IPC IPC(8): H04L5/00H04W74/08
Inventor 索士强王立波潘学明
Owner DATANG MOBILE COMM EQUIP CO LTD