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US-12627547-B2 - Method and apparatus for detecting preamble signal of random access channel in base station of wireless communication system

US12627547B2US 12627547 B2US12627547 B2US 12627547B2US-12627547-B2

Abstract

A preamble reception apparatus and a reception method for extending a range of a base station are provided. The apparatus includes a preamble symbol unit data generator for receiving preamble symbols, a first fast Fourier transformer for fast Fourier transforming each output of the preamble symbol unit data generator, a first sequence generator for generating a preamble sequence, a coverage extension detector configured to calculate symbol power of each of the preamble symbols, calculate a non-coherent sum for each consecutive preamble symbol, combine the non-coherent sums, and detect a maximum energy value among the non-coherent sums and a first delay value (DF) of the preamble symbols having the maximum energy value, a delay ambiguity detector configured to calculate power for two consecutive preamble symbols, and estimate a second delay value (DT) of the preamble symbols, and a preamble determiner for determining whether a preamble is received.

Inventors

  • Hyuncheol Kim

Assignees

  • SAMSUNG ELECTRONICS CO., LTD.

Dates

Publication Date
20260512
Application Date
20230217
Priority Date
20220218

Claims (18)

  1. 1 . An apparatus for detecting a preamble signal of a random access channel in a base station, the apparatus comprising: memory, comprising one or more storage media, storing instructions; and one or more processors communicatively coupled to the memory, wherein the instructions, when executed by the one or more processors individually or collectively, cause the apparatus to: receive preamble symbols for a third time interval via the random access channel for each antenna to convert the preamble symbols into a preamble symbol unit, wherein the third time interval is a sum of a first time interval required for transmission of the preamble symbols forming a preamble body and a second time interval during which two or more preamble symbols are transmitted, perform first fast Fourier transform on symbols including the preamble symbols and the two or more preamble symbols, generate the same preamble sequence as a preamble sequence used in the preamble body, calculate symbol power of each of the preamble symbols using the preamble sequence with respect to the first fast Fourier-transformed symbols for each antenna, for each antenna, calculate a non-coherent sums by adding the calculated symbol power of each preamble symbol across all possible sequences of consecutive preamble symbols within the first time interval, combine the non-coherent sums calculated for the preamble symbols at the same position for each antenna, detect a maximum energy value among the combined non-coherent sums and a first delay value (DF) of the preamble symbols having the maximum energy value, calculate power using the preamble sequence for two consecutive preamble symbols in the preamble symbols received for the third time interval, estimate a second delay value (DT) of the preamble symbols using the power of the two consecutive preamble symbols, and determine whether a preamble is received using the second delay value and the maximum energy value.
  2. 2 . The apparatus of claim 1 , wherein the instructions that, when executed by the one or more processors individually or collectively, further cause the apparatus to: calculate power for each of the first fast Fourier-transformed symbols for each antenna using the generated preamble sequence used in the preamble body; calculate non-coherent sums in units of consecutive preamble symbols within the first time interval for each antenna; combine the non-coherent sum calculated for the preamble symbols at the same position for each antenna by first antenna couplers; and output a maximum energy value among the combined non-coherent sums and a first delay value of the preamble symbols having the maximum energy value using an output of the first antenna couplers.
  3. 3 . The apparatus of claim 2 , wherein the instructions that, when executed by the one or more processors individually or collectively, further cause the apparatus to: perform sequence correlation with the first fast Fourier-transformed symbols using the preamble sequence to generate a sequence-correlated signal; perform first inverse fast Fourier transforming the sequence-correlated signal to generate a first inverse fast Fourier-transformed signal; and calculate power of the first inverse fast Fourier-transformed signal.
  4. 4 . The apparatus of claim 1 , wherein the instructions that, when executed by the one or more processors individually or collectively, further cause the apparatus to: generate a second sequence, based on the generated preamble sequence used in the preamble body; calculate power for two consecutive preamble symbols amongst the received preamble symbols based on the second sequence; and estimate the second delay value based on the first delay value and the calculated power for the two consecutive preamble symbols.
  5. 5 . The apparatus of claim 4 , wherein the instructions that, when executed by the one or more processors individually or collectively, further cause the apparatus to: perform second inverse fast Fourier for transforming the preamble sequence used in the preamble body; output zero values corresponding to a length of the preamble sequence used in the preamble body; and combine the second inverse Fast Fourier-transformed preamble sequence and zero values.
  6. 6 . The apparatus of claim 5 , wherein the instructions that, when executed by the one or more processors individually or collectively, further cause the apparatus to: perform third fast Fourier for transforming the two consecutive preamble symbols at once; calculate second correlation with a second fast Fourier-transformed symbol using the second sequence; perform third inverse Fast Fourier for inverse fast Fourier transforming a value calculated in the second correlation; calculate power for one preamble symbol length from a third inverse fast Fourier transformer output; remove a signal for which a power calculation is not performed; and combining the calculated power for the same preamble symbol for each antenna.
  7. 7 . The apparatus of claim 5 , wherein the instructions that, when executed by the one or more processors individually or collectively, further cause the apparatus to: perform interpolation so that the length is doubled using the preamble sequence.
  8. 8 . The apparatus of claim 7 , wherein the instructions that, when executed by the one or more processors individually or collectively, further cause the apparatus to: calculate a length of one preamble symbol to be doubled for the two consecutive preamble symbols; adding the two consecutive preamble symbols with the doubled length to generate a value; calculating third correlation with the value using the second sequence to generate a third correlated value; perform fourth inverse fast Fourier for inverse fast Fourier transforming the third correlated value to generate a fourth inverse fast Fourier-transformed signal; calculate power for only one preamble symbol length from an output of the fourth inverse fast Fourier transformer in the fourth inverse fast Fourier-transformed signal; remove a signal for which the power calculation is not performed; and combining the calculated power for the same preamble symbol for each antenna.
  9. 9 . The apparatus of claim 1 , wherein the instructions that, when executed by the one or more processors individually or collectively, further cause the apparatus to: determine a reception position of the preamble when it is determined that the preamble has been received.
  10. 10 . A method for detecting a preamble signal of a random access channel in a base station, the method comprising: receiving preamble symbols for a third time interval via the random access channel for each antenna, wherein the third time interval is a sum of a first time interval required for transmission of the preamble symbols forming a preamble body and a second time interval during which two or more preamble symbols are transmitted; dividing the preamble symbols received for the third time interval into one preamble symbol unit; first fast Fourier transforming each of the divided preamble symbols respectively; generating a first preamble sequence that is the same as a preamble sequence used in the preamble body; calculating symbol power of each of the preamble symbols using the preamble sequence with respect to the first fast Fourier-transformed symbols for each antenna; for each antenna, calculating non-coherent sums by adding the calculated symbol power of each preamble symbol across all possible sequences of consecutive preamble symbols within the first time interval; combining the non-coherent sums calculated for the preamble symbols at the same position for each antenna; detecting a maximum energy value amongst the non-coherent sums; generating a first delay value (DF) for the consecutive preamble symbols having the maximum energy value; calculating power using the preamble sequence for two consecutive preamble symbols in the preamble symbols received for the third time interval; estimating a second delay value (DT) of the preamble symbols using the power of the two consecutive preamble symbols; and determining whether a preamble is received using the second delay value and the maximum energy value.
  11. 11 . The method of claim 10 , further comprising: performing sequence correlation with the first fast Fourier-transformed symbols using the first preamble sequence to generate a sequence-correlated signal; inverse fast Fourier transforming the sequence-correlated signal to generate an inverse fast Fourier-transformed signal; and calculating power of the inverse fast Fourier-transformed signal.
  12. 12 . The method of claim 10 , further comprising: generating a second sequence having twice a length of the preamble sequence by using the preamble sequence; calculating second power values for two consecutive preamble symbols from among the received preamble symbols using the second sequence; and estimating the second delay value using the first delay value and the calculated second power values.
  13. 13 . The method of claim 12 , further comprising: performing an inverse fast Fourier transforming the preamble sequence; padding a zero value of the same length to the inverse fast Fourier-transformed preamble sequence; and generating an inverse fast Fourier-transformed signal padded with the zero value by performing fast Fourier transform at a time.
  14. 14 . The method of claim 13 , further comprising: third fast Fourier transforming for fast Fourier transforming the two consecutive preamble symbols at once; second correlating for calculating correlation with a second fast Fourier-transformed symbol using the second sequence; third inverse fast Fourier transforming for inverse Fast Fourier transforming the value calculated in the second correlation; calculating power for only one preamble symbol length from a third inverse fast Fourier-transformed output; removing a signal for which a power calculation is not performed; and combining the calculated power for the same preamble symbol for each antenna.
  15. 15 . The method of claim 13 , further comprising: performing an interpolation so that the length is doubled using the preamble sequence.
  16. 16 . The method of claim 15 , further comprising: calculating a length of one preamble symbol to be doubled, for the two consecutive preamble symbols; adding the two consecutive preamble symbols with the doubled length to generate a value; a third correlation for calculating correlation with the value, using the second sequence; a fourth inverse fast Fourier transformation for inverse fast Fourier transforming the third correlated value to generate a fourth inverse fast Fourier-transformed signal; calculating power for only one preamble symbol length in the fourth inverse fast Fourier-transformed signal; removing a signal for which a power calculation is not performed; and combining the calculated power for the same preamble symbol for each antenna.
  17. 17 . The method of claim 10 , further comprising determining a reception position of the preamble when it is determined that the preamble has been received.
  18. 18 . The method of claim 10 , further comprising calculating, by symbol power calculators, power of each of the preamble symbols fast Fourier transformed by the first fast Fourier transformer for each antenna using the first preamble sequence; calculating non-coherent sums in units of consecutive preamble symbols within the first time interval for each antenna; combining, by first antenna couplers, the non-coherent sum calculated for the preamble symbols at the same position for each antenna; and calculating, by a maximum energy detector, and outputting a maximum energy value among the combined non-coherent sums and a first delay value of the preamble symbols having the maximum energy value using the outputs of the first antenna couplers.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) This application is a continuation application, claiming priority under § 365(c), of an International application No. PCT/KR2023/002169, filed on Feb. 14, 2023, which is based on and claims the benefit of a Korean patent application number 10-2022-0021653, filed on Feb. 18, 2022, in the Korean Intellectual Property Office, and of a Korean patent application number 10-2022-0045396, filed on Apr. 12, 2022, in the Korean Intellectual Property Office, the disclosure of each of which is incorporated by reference herein in its entirety. TECHNICAL FIELD The disclosure relates to a method and an apparatus for extending coverage of a random access channel in a wireless communication system. More particularly, the disclosure relates to a method and an apparatus for receiving a physical random access channel (PRACH) in a base station of a mobile communication system. BACKGROUND ART Typically, a wireless communication system may be implemented with a wireless transmitter and a wireless receiver. Further, when performing bidirectional communication, the wireless transmitter may incorporate the wireless receiver. For example, both a first device and a second device have to incorporate a wireless transmitter and a wireless receiver. A common example of such a wireless communication system may be a mobile communication system according to the standard specification of 3rd generation partnership project (3GPP). The mobile communication system may include a base station having a certain coverage area and at least one mobile communication terminal communicating within the coverage. In order for the base station and at least one mobile communication terminal to communicate with each other, it is first required a scheme for the mobile communication terminal to make connection with the base station. A method proposed for a scheme for a mobile communication terminal to access a base station should essentially perform a procedure in which the mobile communication terminal accesses the base station using a physical random access channel (PRACH). As such, the base station may transmit a predetermined reference signal for the mobile communication terminal to make access, and the mobile communication terminal may perform a random access procedure based on the received reference signal. Further, a mobile communication system of the related art has developed from a second generation communication system focusing on voice communication to a third generation (3G) communication system and a fourth generation (4G) communication system for data communication. According to this trend, a New Radio communication system, i.e., a fifth generation (5G) communication system, has been commercialized and used as a communication system capable of more various types of data communication. Meanwhile, in a mobile communication system, a code division multiple access (CDMA) method and an orthogonal frequency-division multiple access (OFDMA) method are in use. Amongst them, the OFDMA method is mainly used in data communication in recent years, and it has been in wide use in communication technology based on the 3GPP standard. Furthermore, as the mobile communication system develops with this trend, each mobile communication system uses a higher frequency band, and as the communication generation more progresses from the 3G communication system, the higher frequency band is used than the communication system of the related art. As described above, as the mobile communication systems developed later use a higher frequency band, there is a problem in that the distance and/or range through which a signal can be transmitted is narrowed according to the characteristics of radio waves. As a result, the base station has a problem that it may become more and more difficult to receive PRACH transmitted by the mobile communication terminal. Reducing the coverage of the base station will require an additional burden of high cost on the part of a service provider providing the mobile communication service, which in turn leads to a burden on the user. For example, the number of base stations required further increases when the coverage of a base station has a radius of 5 km, compared to where the coverage of a base station has a radius of 10 km. Hence, if it is an urban area with many users, it may be necessary to increase the number of the base stations. However, there is an aspect that it is difficult to accommodate all the requirements where the density of population requiring communication is significantly low or irregular, such as in a rural area or a resort area with few users. Therefore, although the service providers usually wish to take a wider coverage of the base station, the technical standard only proposes a scheme suitable for fairness based on both the densely populated area and the sparsely populated area. If the structure of PRACH itself is changed to address such a problem, modification should be made on the st