Patent Description:
For a ground <NUM>th-Generation (<NUM>) mobile communication system, a bandwidth of its single carrier is defined in accordance with integral multiples of <NUM> at a high frequency band, e.g., <NUM> as a minimum value, <NUM>, <NUM> or <NUM>. Taking a sub-carrier spacing of <NUM> as an example, specific parameters at the bandwidths are shown in Table <NUM>. The setting of a random access channel is not affected on the basis of this bandwidth definition.

For a satellite mobile communication system adopting the ground <NUM> system, the minimum bandwidth of the ground <NUM> system is defined as <NUM> in the case of the high frequency band. Due to the restraint on transmission power of a terminal, it is difficult for an uplink transmission bandwidth of the terminal at a low power level to reach the minimum bandwidth defined in the ground <NUM> system, so it is impossible for the minimum bandwidth to be adapted to the access of a satellite terminal at a low power level.

<CIT> discloses method and apparatus for allocating a frequency resource for transmitting and receiving a random access channel and transmitting and receiving the random access channel through the allocated frequency resource.

Document of <NPL>), discloses random access channel structure and random access procedure for an NR cell which is configured with multiple numerologies (i.e. subcarrier spacing).

Document of <NPL>), discloses an issues for the DL/UL synchronization and PRACH design for the Non-Terrestrial Network (NTN).

A technical specification produced by the <NUM>rd Generation Partnership Project (3GPP), namely 3GPP TS <NUM> V15. <NUM> (<NUM>-<NUM>) (<NPL>), discloses physical channels and modulation of the Evolved Universal Terrestrial Radio Access (E-UTRA).

An object of the present disclosure is to provide methods for selecting and configuring a random access channel, an access device and a network device, so as to solve the problem that the minimum bandwidth defined in the ground <NUM> system is large in the case of the high frequency band and it is impossible for the minimum bandwidth to be adapted to the access of the satellite terminal at a low power level.

The present disclosure has the following beneficial effects.

According to the embodiments of the present disclosure, the parameter information and the time-frequency resource allocation information corresponding to the at least two types of random access channels are obtained, the target parameter information is selected from the parameter information in accordance with the capability of the access device, the operating scenario of the access device and the frequency offset proportion of the random access channel, the random access channel is selected in accordance with the target parameter information, and then the random access signal is transmitted in accordance with the time-frequency resource allocation information. Through the parameter information, it is able for the random access channel bandwidth to match a power level of the satellite access device, so as to meet a requirement on a signal-to-noise ratio for the system. In addition, a parameter of the random access channel is selected in such a manner as to approximate to that for a ground <NUM> system, so it is able for a satellite mobile communication system to make full use of an industrial advantages of the ground <NUM> system for development.

The present invention is defined by the attached independent claims. Advantageous embodiments are described in the attached dependent claims. Embodiments and/or examples mentioned in the description that do not fall under the scope of the claims are useful for understanding the present invention.

The present disclosure will be described hereinafter in conjunction with the drawings and embodiments. The following embodiments are for illustrative purposes only, but shall not be used to limit the scope of the present disclosure. Actually, the embodiments are provided so as to facilitate the understanding of the scope of the present disclosure. Such words as "first" and "second" involved in the specification and the appended claims are merely used to differentiate different objects rather than to represent any specific order. It should be appreciated that, the data used in this way may be replaced with each other, so as to implement the embodiments in an order other than that shown in the drawings or described in the specification. In addition, such terms as "include" or "including" or any other variations involved in the present disclosure intend to provide non-exclusive coverage, so that a procedure, method, system, product or device including a series of steps or units may also include any other elements not listed herein, or may include any inherent steps or units of the procedure, method, system, product or device. The expression "and/or" involved in the embodiments of the present disclosure may represent at least one of listed items.

The following description is given for illustrative purposes but shall not be construed as limiting the scope, applicability or configuration set forth in the appended claims. Any alterations may be made on functions and arrangements of the discussed elements without departing from the scope of the present disclosure. Various procedures or assemblies may be omitted, replaced or added appropriately in the examples. For example, steps of the described method may be performed in an order different from that described in the context, and some steps may be added, omitted or combined. In addition, the features described with reference to some examples may be combined in the other examples.

As shown in <FIG>, the present disclosure provides in some embodiments a method for selecting a random access channel for an access device. The access device may be specifically a User Equipment (UE) or terminal, a base station, or a relay node.

Step <NUM>: obtaining parameter information and time-frequency resource allocation information corresponding to at least two types of random access channels. The parameter information corresponding to each type of random access channel includes a subcarrier spacing and a preamble sequence, a random access channel bandwidth obtained in accordance with the subcarrier spacing and a length of the preamble sequence is smaller than or equal to a maximum transmission bandwidth of a satellite access device, and the subcarrier spacing includes a reference value of a maximum frequency offset to be resisted by a satellite system.

In the embodiments of the present disclosure, the random access channel bandwidth is obtained in accordance with a product of the length of the preamble sequence and the subcarrier spacing. The maximum transmission bandwidth of the satellite access device includes a bandwidth defined by a ground communication system and a bandwidth supported by the satellite system.

The ground communication system may be specifically a ground <NUM> communication system. The bandwidths defined by the ground <NUM> communication system include <NUM>, <NUM>, <NUM> and <NUM>. The bandwidths supported by the satellite system include narrows bands, i.e., <NUM> and <NUM>*nMHz (n<<NUM>), and a broadband, i.e., <NUM>*nMHz (n≤<NUM>).

The preamble sequences in the parameter information corresponding to different random access channels have different lengths, and/or the subcarrier spacings in the parameter information corresponding to different random access channels are different. In the embodiments of the present disclosure, apart from the reference value of the maximum frequency offset to be resisted by the satellite system, the subcarrier spacing of the random access channel further includes a reference value defined by the ground communication system.

The reference values defined by the ground communication system are specifically reference values defined by the ground <NUM> communication system, e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>. For the reference value of the maximum frequency offset to be resisted by the satellite system, apart from the reference value defined by the ground <NUM> communication system, a larger frequency offset, e.g., <NUM> or <NUM>, may be taken into consideration, or a refined value may be selected within an existing frequency offset range, e.g., within a range from <NUM> to <NUM>.

In the embodiments of the present disclosure, the structure of the random access channel is a preamble sequence with a Cyclic Prefix (CP) and predetermined repetition times. The preamble sequence is defined on the basis of a Zadoff Chu (ZC) sequence or an m sequence, and typically the preamble sequence has a length of <NUM> or <NUM>.

The repetition times of the preamble sequence are associated with the length of the preamble sequence and a frequency offset proportion of the random access channel. To be specific, the repetition times of the preamble sequence are in reverse proportion to a length of the preamble sequence, and in direct proportion to a frequency offset proportion of the random access channel. In other words, the longer the preamble, the fewer the repetition times of the preamble; the shorter the preamble, the more the repetition times of the preamble; the smaller the frequency offset proportion of the random access channel, the fewer the repetition times of the preamble; and the larger the frequency offset proportion of the random access channel, the more the repetition times of the preamble. The frequency offset proportion of the random access channel=the maximum frequency offset to be resisted by the system/the subcarrier spacing.

Step <NUM>: selecting target parameter information from the parameter information in accordance with a capability of the access device, an operating scenario of the access device and the frequency offset proportion of the random access channel.

Here, the capability of the access device includes a maximum transmission bandwidth of the access device, and the operating scenario of the access device specifically includes an aircraft-mounted terminal, a ship-mounted terminal, a train-mounted terminal, a vehicle-mounted terminal, etc..

The target parameter information includes a target random access channel bandwidth, a target subcarrier spacing and a target preamble sequence.

Step <NUM>: selecting a random access channel in accordance with the target parameter information, and transmitting a random access signal in accordance with the time-frequency resource allocation information.

Here, subsequent to determining the target parameter information, a corresponding random access channel is selected in accordance with the target parameter information. According to the method for selecting the random access channel in the embodiments of the present disclosure, the parameter information and the time-frequency resource allocation information corresponding to the at least two types of random access channels are obtained, the target parameter information is selected from the parameter information in accordance with the capability of the access device, the operating scenario of the access device and the frequency offset proportion of the random access channel, the random access channel is selected in accordance with the target parameter information, and then the random access signal is transmitted in accordance with the time-frequency resource allocation information. Through the parameter information, it is able for the random access channel bandwidth to match a power level of the satellite access device, so as to meet a requirement on a signal-to-noise ratio for the system. In addition, a parameter of the random access channel is selected in such a manner as to approximate to that for a ground <NUM> system, so it is able for a satellite mobile communication system to make full use of an industrial advantages of the ground <NUM> system for development.

In a possible embodiment of the present disclosure, the selecting the target parameter information from the parameter information in accordance with the capability of the access device, the operating scenario of the access device and the frequency offset proportion of the random access channel includes: selecting a target random access channel bandwidth smaller than or equal to a maximum transmission bandwidth of the access device from the parameter information in accordance with the capability of the access device; selecting from the parameter information a target subcarrier spacing greater than the maximum frequency offset to be resisted by the access device in accordance with the operating scenario of the access device; and selecting a target preamble sequence from the parameter information in accordance with the frequency offset proportion of the random access channel.

Further, the selecting the target preamble sequence from the parameter information in accordance with the frequency offset proportion of the random access channel includes: in the case that there is a plurality of same preamble sequences in the parameter information, selecting preamble sequences with a minimum frequency offset proportion from the plurality of same preamble sequences to obtain a target preamble sequence set; in the case that the target preamble sequence set includes different preamble sequences, determining the target preamble sequence in accordance with a frequency offset proportion of a random access channel corresponding to a shortest preamble sequence in the target preamble sequence set; and in the case that the target preamble sequence set does not include different preamble sequences, determining the preamble sequence in the target preamble sequence set as the target preamble sequence.

Further, the determining the target preamble sequence in accordance with the frequency offset proportion of the random access channel corresponding to the shortest preamble sequence in the target preamble sequence set includes: in the case that the frequency offset proportion of the random access channel corresponding to the shortest preamble sequence in the target preamble sequence set is smaller than or equal to a first predetermined threshold, selecting the shortest preamble sequence as the target preamble sequence; in the case that the frequency offset proportion of the random access channel corresponding to the shortest preamble sequence in the target preamble sequence set is greater than or equal to a second predetermined threshold, selecting a longest preamble sequence as the target preamble sequence; and in the case that the frequency offset proportion of the random access channel corresponding to the shortest preamble sequence in the target preamble sequence set is greater than the first predetermined threshold and smaller than the second predetermined threshold, selecting a preamble sequence corresponding to a minimum random access channel bandwidth as the target preamble sequence, the second predetermined threshold being greater than the first predetermined threshold.

For example, the first predetermined threshold is specifically <NUM>%, and the second predetermined threshold is specifically <NUM>%.

According to the method for selecting the random access channel in the embodiments of the present disclosure, the parameter information and the time-frequency resource allocation information corresponding to the at least two types of random access channels are obtained, the target parameter information is selected from the parameter information in accordance with the capability of the access device, the operating scenario of the access device and the frequency offset proportion of the random access channel, the random access channel is selected in accordance with the target parameter information, and then the random access signal is transmitted in accordance with the time-frequency resource allocation information. Through the parameter information, it is able for the random access channel bandwidth to match a power level of the satellite access device, so as to meet a requirement on a signal-to-noise ratio for the system. In addition, a parameter of the random access channel is selected in such a manner as to approximate to that for a ground <NUM> system, so it is able for a satellite mobile communication system to make full use of an industrial advantages of the ground <NUM> system for development.

As shown in <FIG>, the present disclosure further provides in some embodiments a method for configuring a random access channel for a network device. The network device specifically includes a satellite, a ground base station or a gateway. The method includes: Step <NUM> of configuring parameter information and time-frequency resource allocation information corresponding to at least two types of random access channels; and Step <NUM> of notifying the parameter information and the time-frequency resource allocation information corresponding to the at least two types of random access channels to an access device. The parameter information corresponding to each type of random access channel includes a subcarrier spacing and a preamble sequence, a random access channel bandwidth obtained in accordance with the subcarrier spacing and a length of the preamble sequence is smaller than or equal to a maximum transmission bandwidth of a satellite access device, and the subcarrier spacing includes a reference value of a maximum frequency offset to be resisted by a satellite system. The preamble sequences in the parameter information corresponding to different random access channels have different lengths, and/or the subcarrier spacings in the parameter information corresponding to different random access channels are different. In the embodiments of the present disclosure, the random access channel bandwidth is obtained in accordance with a product of the length of the preamble sequence and the subcarrier spacing. The maximum transmission bandwidth of the satellite access device includes a bandwidth defined by a ground communication system and a bandwidth supported by the satellite system.

In the embodiments of the present disclosure, apart from the reference value of the maximum frequency offset to be resisted by the satellite system, the subcarrier spacing of the random access channel further includes a reference value defined by the ground communication system.

The parameter information corresponding to each type of random access channel further includes repetition times of the preamble sequence of the random access channel, and the repetition times of the preamble sequence of the random access channel are associated with the length of the preamble sequence and a frequency offset proportion of the random access channel.

To be specific, the repetition times of the preamble sequence are in reverse proportion to a length of the preamble sequence, and in direct proportion to a frequency offset proportion of the random access channel.

Further, the maximum transmission bandwidth of the satellite access device includes a bandwidth defined by a ground communications system and a bandwidth supported by the satellite system.

According to the method for configuring the random access channel in the embodiments of the present disclosure, the parameter information and the time-frequency resource allocation information corresponding to the at least two types of random access channels are configured, and then the parameter information and the time-frequency resource allocation information corresponding to the at least two types of random access channels are notified to the access device. Through the parameter information, it is able for the random access channel bandwidth to match a power level of the satellite access device, so as to meet a requirement on a signal-to-noise ratio for the system. In addition, a parameter of the random access channel is selected in such a manner as to approximate to that for a ground <NUM> system, so it is able for a satellite mobile communication system to make full use of an industrial advantages of the ground <NUM> system for development. The present disclosure will be described hereinafter in more details in conjunction with the embodiments.

When the access device is a terminal, two carrier types, i.e., a carrier within a frequency range FR1 (<<NUM>) and a carrier within a frequency range FR2 (><NUM>), are defined by the ground <NUM> system. For a traffic channel, a bandwidth of a single carrier within the range FR1 is defined as an integral multiple of <NUM>, with a maximum value of <NUM> and principally including three subcarrier spacings, i.e., <NUM>, <NUM> and <NUM>. A bandwidth of a single carrier within the range FR2 is defined as an integral multiple of <NUM>, with a maximum value of <NUM> and principally including a subcarrier spacing of <NUM> or more. For a random access channel, as shown in <FIG>, its basic form consists of one CP and a preamble sequence (preamble) repeated for multiple times. A length of the preamble and a subcarrier spacing within the range FR1 principally include <NUM>*<NUM>, <NUM>*<NUM>, <NUM>*<NUM> or <NUM>*<NUM>, and a length of the preamble and a subcarrier spacing within the range FR2 principally include <NUM>*<NUM> or <NUM>* <NUM>. Hence, a bandwidth of a random access channel within the range FR1 is <NUM> to <NUM>. <NUM>, which is smaller than a minimum single-carrier bandwidth, i.e., <NUM>, and it means that the random access channel width is not limited. Identically, a bandwidth of a random access channel within the range FR2 is <NUM> to <NUM>, which is smaller than a minimum single-carrier bandwidth, i.e., <NUM>, and it means that the random access channel width is not limited either. When the access device is a terminal, for the satellite communication system, the cost of the terminal is associated with its maximum transmission power, and the terminal with low cost has smaller maximum transmission power. Because the power and the bandwidth are resources of the system, small transmission power corresponds to small transmission bandwidth. Taking a Little Earth Orbit (LEO) system at a Ka frequency band as an example, with reference to a bandwidth design of the ground <NUM> system, although the single-carrier bandwidth for the satellite is defined as <NUM>, a terminal with a small aperture has low Effective Isotropic Radiated Power (EIRP). When a large bandwidth is adopted for transmission, inevitably a signal-to-noise ratio of a receiver is very low, and it is difficult to demodulate a signal. Hence, usually an actual maximum bandwidth of the terminal for transmission is associated with a maximum EIRP value. Table <NUM> shows an instance of a transmission capability of the terminal. As shown in Table <NUM>, a terminal with an aperture of <NUM> is capable of satisfying the minimum transmission bandwidth of <NUM> defined in the ground <NUM> system, and each of the other three terminals with different apertures has a maximum transmission bandwidth smaller than that defined in the ground <NUM> system and thereby probably does not satisfy the requirement on the bandwidth of the random access channel. For example, the terminal with an aperture of <NUM> has a maximum transmission bandwidth of <NUM>, which is smaller than a bandwidth of a random access channel using a <NUM>*<NUM> preamble sequence, i.e., <NUM>; and the terminal with an aperture of <NUM> has a maximum transmission bandwidth of <NUM>, which is smaller than a bandwidth of a random access channel using a <NUM>*<NUM> preamble sequence, i.e., <NUM>. The maximum transmission bandwidth supported by the terminal is smaller than the random access channel width, so it is necessary to re-design the random access channel, including the length of the preamble sequence, the subcarrier spacing, the repetition times, etc..

The design of the preamble sequence is associated with various factors such as frequency offset resistance, the quantity of concurrent users and system overhead. Usually, when the frequency offset is larger, it means that the preamble sequence needs to be provided with a larger subcarrier spacing; when the quantity of the concurrent users is larger, it means that the preamble sequence needs to be provided with better anti-Multiple Access Interference (MAI) capability and with a larger length; and when the system overhead is larger, it means that a larger time-frequency resource for random access is available and the preamble is capable of being repeated in more times. Hence, during the design of the preamble sequence, these factors need to be taken into consideration. On the basis of a detection test, usually a maximum tolerance of the system to the frequency offset is once of the subcarrier spacing, so the subcarrier spacing of the preamble sequence may be taken into consideration preferentially. Without loss of generality, taking a high-frequency LEO satellite mobile communication system designed with reference to the ground <NUM> system as an example, its random access channel is designed as follows.

A maximum bandwidth supported by the random access channel is defined. Usually, a designed bandwidth of the random access channel is smaller than or equal to a maximum bandwidth of a traffic channel, i.e., BWRACH≤BWdata. For a terminal with a large aperture, the bandwidth of the traffic channel is obviously larger than the bandwidth of the random access channel, so the bandwidth of the random access channel may be set with reference to the ground <NUM> system. For a terminal with a small aperture, in order to make full use of the transmission power or achieve a balance between the bandwidth of the traffic channel and the bandwidth of the access channel as possible, the designed bandwidth of the random access channel may be directly defined as the maximum bandwidth of the traffic channel. With respect to Table <NUM>, the bandwidths of the random access channels for various terminals are shown in Table <NUM>.

The Subcarrier Spacing (SCS) of the random access channel is defined. Usually, the subcarrier spacing SCS should be smaller than or equal to the maximum frequency offset to be resisted, i.e., SCS≤Δf. In a random access process, the maximum frequency offset to be resisted usually at least includes two parts, one from a residual frequency offset generated after the frequency offset caused by the movement of the satellite has been suppressed by the system, and the other from the movement of the terminal itself. With respect to Table <NUM>, frequency offset estimates and the subcarrier spacings for various terminals are shown in Table <NUM>.

The preamble is designed. A maximum length of the preamble may be determined in accordance with the random access channel bandwidth and the SCS, and then the preamble sequence is selected with reference to codes defined in the ground <NUM> system (which are generated using a Zadoff-Chu sequence and have two lengths, i.e., <NUM> and <NUM>), so that the length of the selected preamble sequence is smaller than or equal to a maximum code length. With respect to Table <NUM>, the preambles for various terminals are shown in Table <NUM>.

The SCS is adjusted and the transmission times of the preamble are defined. Considering that the system's resistance to frequency offset is stronger in the case of a larger redundancy level of the SCS relative to the frequency offset, the SCS of the selected preamble may be further adjusted, e.g., the SCS may be increased as possible, or the SCS defined in the ground <NUM> system may be selected as possible, as long as the adjusted bandwidth is smaller than the designed random access channel bandwidth. In addition, the appropriate transmission times of the preamble may be designed in accordance with an anti-frequency offset percentage of the preamble, on the basis of such a principle as to ensure the detection performance of a receiver and reduce the system overhead as possible. Usually, the Zadoff-Chu sequence having a length of <NUM> needs to be repeated for more than four times so as to resist <NUM>% or more of the frequency offset, and the Zadoff-Chu sequence having a length of <NUM> does not need to be repeated to resist <NUM>% of the frequency offset. With respect to Tables <NUM> to <NUM>, parameters of the random access channel for various terminals are shown in Table <NUM>.

Based on the above design ideas, it is able to design a summary sheet of the parameters of the random access channel conforming to the ground <NUM> system and satisfying the specific requirements on the high-frequency LEO satellite mobile communication system. Table <NUM> shows an example. Table <NUM> includes the preamble sequences having different lengths, and each preamble sequence includes the SCSs at different granularity levels. This table includes typical formats defined in the ground <NUM> system, and new typical formats in the satellite mobile communication system. Hence, the random access channel on the basis of this table may reflect access requirements for various terminals in the satellite mobile communication system.

The designed parameters of the random access channel in the table may be used as agreed parameters of the system, so that the terminal selects an appropriate format for access. Without loss of generality, taking the above-mentioned high-frequency LEO satellite mobile communication system as an example, the terminal may select the parameters of the random access channel as follows.

The bandwidth of the random access channel is selected. The random access channel bandwidth to be supported needs to be smaller than or equal to the maximum transmission bandwidth of the traffic channel. With respect to Table <NUM>, potential formats of the random access channel for various terminals are shown in Table <NUM>.

The SCS of the random access channel is selected. The SCS to be supported needs to be greater than the maximum frequency offset to be resisted. With respect to Table <NUM>, on the basis of Table <NUM>, the potential formats of the random access channel for various terminals are shown in Table <NUM>.

A unique value of a same root sequence of the random access channel is selected. When there is a plurality of same root sequence formats, a format with a minimum frequency offset proportion is selected with respect to the root sequences. With respect to Table <NUM>, on the basis of Table <NUM>, the potential formats of the random access channel for various terminals are shown in Table <NUM>.

Unique values of different root sequences of the random access channel are selected. When there are different root sequence formats, further judgment is performed in accordance with a frequency offset proportion of a shortest sequence (i.e., a sequence having a length of <NUM>). When the frequency offset proportion≤<NUM>%, a format of the sequence having a length of <NUM> is selected; when the frequency offset proportion≥<NUM>%, a format of the sequence having a length of <NUM> is selected; when the frequency offset proportion is greater than <NUM>% and smaller than <NUM>%, a format with a minimum random access channel bandwidth is selected. With respect to Table <NUM>, on the basis of Table <NUM>, the formats of the random access channel finally selected by various terminals are shown in Table <NUM>. As shown in Table <NUM>, for the terminals with an aperture of <NUM> and an aperture of <NUM>, the format <NUM> may be selected as a parameter design of the random access channel; for the terminal with an aperture of <NUM>, the format <NUM> may be selected as a parameter design of the random access channel; and for the terminal with an aperture of <NUM>, the format <NUM> may be selected as a parameter design of the random access channel.

According to the embodiments of the present disclosure, through designing the satellite mobile communication system in accordance with the ground <NUM> system, it is able for the designed random access channel bandwidth to match a power level of the terminal, so as to meet a requirement on a signal-to-noise ratio for the system. In addition, the parameter of the random access channel is selected in such a manner as to approximate to that for a ground <NUM> system, so it is able for a satellite mobile communication system to make full use of an industrial advantages of the ground <NUM> system for development. As shown in <FIG>, the present disclosure further provides in some embodiments an access device, which includes a transceiver, a memory, a processor, and a computer program stored in the memory and capable of being executed by the processor. The processor is configured to execute the computer program so as to: obtain parameter information and time-frequency resource allocation information corresponding to at least two types of random access channels, the parameter information corresponding to each type of random access channel including a subcarrier spacing and a preamble sequence, a random access channel bandwidth obtained in accordance with the subcarrier spacing and a length of the preamble sequence being smaller than or equal to a maximum transmission bandwidth of a satellite access device, the subcarrier spacing including a reference value of a maximum frequency offset to be resisted by a satellite system; select target parameter information from the parameter information in accordance with a capability of the access device, an operating scenario of the access device and a frequency offset proportion of the random access channel; and select a random access channel in accordance with the target parameter information, and transmit a random access signal in accordance with the time-frequency resource allocation information.

In <FIG>, bus architecture includes a number of buses and bridges connected to each other, so as to connect various circuits for one or more processors <NUM> and one or more memories <NUM>. In addition, as is known in the art, the bus architecture may be used to connect any other circuits, such as a circuit for a peripheral device, a circuit for a voltage stabilizer and a power management circuit. A bus interface is provided, and the transceiver <NUM> consists of a plurality of elements, i.e., a transmitter and a receiver for communication with any other devices over a transmission medium. With respect to different terminals, a user interface <NUM> is also provided for devices which are to be arranged inside or outside the terminal, and these devices may include but not limited to a keypad, a display, a speaker, a microphone and a joystick. The processor <NUM> takes charge of managing the bus architecture as well as general processings. The memory <NUM> stores therein data for the operation of the processor <NUM>.

In a possible embodiment of the present disclosure, when selecting the target parameter information from the parameter information in accordance with the capability of the access device, the operating scenario of the access device and the frequency offset proportion of the random access channel, the processor <NUM> is further configured to execute the program, so as to: select a target random access channel bandwidth smaller than or equal to a maximum transmission bandwidth of the access device from the parameter information in accordance with the capability of the access device; select from the parameter information a target subcarrier spacing greater than the maximum frequency offset to be resisted by the access device in accordance with the operating scenario of the access device; and select a target preamble sequence from the parameter information in accordance with the frequency offset proportion of the random access channel.

In a possible embodiment of the present disclosure, when selecting the target preamble sequence from the parameter information in accordance with the frequency offset proportion of the random access channel, the processor <NUM> is further configured to execute the program to: in the case that there is a plurality of same preamble sequences in the parameter information, select preamble sequences with a minimum frequency offset proportion from the plurality of same preamble sequences to obtain a target preamble sequence set; in the case that the target preamble sequence set includes different preamble sequences, determine the target preamble sequence in accordance with a frequency offset proportion of a random access channel corresponding to a shortest preamble sequence in the target preamble sequence set; and in the case that the target preamble sequence set does not include different preamble sequences, determine the preamble sequence in the target preamble sequence set as the target preamble sequence.

In a possible embodiment of the present disclosure, when determining the target preamble sequence in accordance with the frequency offset proportion of the random access channel corresponding to the shortest preamble sequence in the target preamble sequence set, the processor <NUM> is further configured to execute the program to: in the case that the frequency offset proportion of the random access channel corresponding to the shortest preamble sequence in the target preamble sequence set is smaller than or equal to a first predetermined threshold, select the shortest preamble sequence as the target preamble sequence; in the case that the frequency offset proportion of the random access channel corresponding to the shortest preamble sequence in the target preamble sequence set is greater than or equal to a second predetermined threshold, select a longest preamble sequence as the target preamble sequence; and in the case that the frequency offset proportion of the random access channel corresponding to the shortest preamble sequence in the target preamble sequence set is greater than the first predetermined threshold and smaller than the second predetermined threshold, select a preamble sequence corresponding to a minimum random access channel bandwidth as the target preamble sequence, the second predetermined threshold being greater than the first predetermined threshold.

In a possible embodiment of the present disclosure, the parameter information corresponding to each type of random access channel further includes repetition times of the preamble sequence of the random access channel. Subsequent to obtaining the parameter information corresponding to the at least two types of random access channels, the processor <NUM> is further configured to execute the program to determine the repetition times of the preamble sequence of the random access channel in accordance with the parameter information.

In a possible embodiment of the present disclosure, the repetition times of the preamble sequence are in reverse proportion to a length of the preamble sequence, and in direct proportion to a frequency offset proportion of the random access channel.

The program is executed by the processor <NUM> so as to implement the above-mentioned method for selecting the random access channel at an access device side with a same technical effect, which will not be particularly defined herein.

The present disclosure further provides in some embodiments a computer-readable storage medium storing therein a computer program. The computer program is configured to be executed by a processor to: obtain parameter information and time-frequency resource allocation information corresponding to at least two types of random access channels, the parameter information corresponding to each type of random access channel including a subcarrier spacing and a preamble sequence, a random access channel bandwidth obtained in accordance with the subcarrier spacing and a length of the preamble sequence being smaller than or equal to a maximum transmission bandwidth of a satellite access device, the subcarrier spacing including a reference value of a maximum frequency offset to be resisted by a satellite system; select target parameter information from the parameter information in accordance with a capability of the access device, an operating scenario of the access device and a frequency offset proportion of the random access channel; and select a random access channel in accordance with the target parameter information, and transmit a random access signal in accordance with the time-frequency resource allocation information. The program is executed by the processor so as to implement the above-mentioned method for selecting the random access channel at an access device side with a same technical effect, which will not be particularly defined herein.

As shown in <FIG>, the present disclosure further provides in some embodiments an access device, which includes: a first obtaining module <NUM> configured to obtain parameter information and time-frequency resource allocation information corresponding to at least two types of random access channels, the parameter information corresponding to each type of random access channel including a subcarrier spacing and a preamble sequence, a random access channel bandwidth obtained in accordance with the subcarrier spacing and a length of the preamble sequence being smaller than or equal to a maximum transmission bandwidth of a satellite access device, the subcarrier spacing including a reference value of a maximum frequency offset to be resisted by a satellite system; a first election module <NUM> configured to select target parameter information from the parameter information in accordance with a capability of the access device, an operating scenario of the access device and a frequency offset proportion of the random access channel; and a second selection module <NUM> configured to select a random access channel in accordance with the target parameter information, and transmit a random access signal in accordance with the time-frequency resource allocation information.

In a possible embodiment of the present disclosure, the first selection module includes: a first selection sub-module configured to select a target random access channel bandwidth smaller than or equal to a maximum transmission bandwidth of the access device from the parameter information in accordance with the capability of the access device; a second selection sub-module configured to select from the parameter information a target subcarrier spacing greater than the maximum frequency offset to be resisted by the access device in accordance with the operating scenario of the access device; and a third selection sub-module configured to select a target preamble sequence from the parameter information in accordance with the frequency offset proportion of the random access channel.

In a possible embodiment of the present disclosure, the third selection sub-module includes: a selection unit configured to, in the case that there is a plurality of same preamble sequences in the parameter information, select preamble sequences with a minimum frequency offset proportion from the plurality of same preamble sequences to obtain a target preamble sequence set; a first determination unit configured to, in the case that the target preamble sequence set includes different preamble sequences, determine the target preamble sequence in accordance with a frequency offset proportion of a random access channel corresponding to a shortest preamble sequence in the target preamble sequence set; and a second determination unit configured to, in the case that the target preamble sequence set does not include different preamble sequences, determine the preamble sequence in the target preamble sequence set as the target preamble sequence.

In a possible embodiment of the present disclosure, the first determination unit includes: a first selection sub-unit configured to, in the case that the frequency offset proportion of the random access channel corresponding to the shortest preamble sequence in the target preamble sequence set is smaller than or equal to a first predetermined threshold, select the shortest preamble sequence as the target preamble sequence; a second selection sub-unit configured to, in the case that the frequency offset proportion of the random access channel corresponding to the shortest preamble sequence in the target preamble sequence set is greater than or equal to a second predetermined threshold, select a longest preamble sequence as the target preamble sequence; and a third selection sub-unit configured to, in the case that the frequency offset proportion of the random access channel corresponding to the shortest preamble sequence in the target preamble sequence set is greater than the first predetermined threshold and smaller than the second predetermined threshold, select a preamble sequence corresponding to a minimum random access channel bandwidth as the target preamble sequence, the second predetermined threshold being greater than the first predetermined threshold. In a possible embodiment of the present disclosure, the parameter information corresponding to each type of random access channel further includes repetition times of the preamble sequence of the random access channel. The access device further includes a determination module configured to, subsequent to obtaining the parameter information corresponding to the at least two types of random access channels, determine the repetition times of the preamble sequence of the random access channel in accordance with the parameter information.

According to the access device in the embodiments of the present disclosure, the parameter information and the time-frequency resource allocation information corresponding to the at least two types of random access channels are obtained, the target parameter information is selected from the parameter information in accordance with the capability of the access device, the operating scenario of the access device and the frequency offset proportion of the random access channel, the random access channel is selected in accordance with the target parameter information, and then the random access signal is transmitted in accordance with the time-frequency resource allocation information. Through the parameter information, it is able for the random access channel bandwidth to match a power level of the satellite access device, so as to meet a requirement on a signal-to-noise ratio for the system. In addition, a parameter of the random access channel is selected in such a manner as to approximate to that for a ground <NUM> system, so it is able for a satellite mobile communication system to make full use of an industrial advantages of the ground <NUM> system for development.

The access device in the embodiments of the present disclosure is capable of implementing the above-mentioned method for selecting the random access channel at an access device side with a same technical effect, which will not be particularly defined herein.

As shown in <FIG>, the present disclosure further provides in some embodiments a network device, e.g., a base station, which includes a memory <NUM>, a processor <NUM>, a transceiver <NUM>, a bus interface, and a program stored in the memory <NUM> and executed by the processor <NUM>. The processor <NUM> is configured to read the program in the memory <NUM>, so as to: configure parameter information corresponding to at least two types of random access channels; and notify the parameter information and the time-frequency resource allocation information corresponding to the at least two types of random access channels to an access device. The parameter information corresponding to each type of random access channel includes a subcarrier spacing and a preamble sequence, a random access channel bandwidth obtained in accordance with the subcarrier spacing and a length of the preamble sequence is smaller than or equal to a maximum transmission bandwidth of a satellite access device, and the subcarrier spacing includes a reference value of a maximum frequency offset to be resisted by a satellite system.

In <FIG>, bus architecture includes a number of buses and bridges connected to each other, so as to connect various circuits for one or more processors <NUM> and one or more memories <NUM>. In addition, as is known in the art, the bus architecture may be used to connect any other circuits, such as a circuit for a peripheral device, a circuit for a voltage stabilizer and a power management circuit. The bus interface is provided, and the transceiver <NUM> consists of a plurality of elements, i.e., a transmitter and a receiver for communication with any other devices over a transmission medium. The processor <NUM> takes charge of managing the bus architecture as well as general processings. The memory <NUM> stores therein data for the operation of the processor <NUM>.

In a possible embodiment of the present disclosure, the preamble sequences in the parameter information corresponding to different random access channels have different lengths, and/or the subcarrier spacings in the parameter information corresponding to different random access channels are different.

In a possible embodiment of the present disclosure, the parameter information corresponding to each type of random access channel further includes repetition times of the preamble sequence of the random access channel, and the repetition times of the preamble sequence of the random access channel are associated with the length of the preamble sequence and a frequency offset proportion of the random access channel. In a possible embodiment of the present disclosure, the repetition times of the preamble sequence are in reverse proportion to a length of the preamble sequence, and in direct proportion to a frequency offset proportion of the random access channel.

In a possible embodiment of the present disclosure, the maximum transmission bandwidth of the satellite access device includes a bandwidth defined by a ground communications system and a bandwidth supported by the satellite system.

According to the network device in the embodiments of the present disclosure, the parameter information and the time-frequency resource allocation information corresponding to the at least two types of random access channels are configured, and then notified to the access device. Through the parameter information, it is able for the random access channel bandwidth to match a power level of the satellite access device, so as to meet a requirement on a signal-to-noise ratio for the system. In addition, a parameter of the random access channel is selected in such a manner as to approximate to that for a ground <NUM> system, so it is able for a satellite mobile communication system to make full use of an industrial advantages of the ground <NUM> system for development. The program is executed by the processor <NUM>, so as to implement the above-mentioned method for configuring the random access channel at a network device side with a same technical effect, which will not be particularly defined herein.

The present disclosure further provides in some embodiments a computer-readable storage medium storing a computer program. The computer program is executed by a processor, so as to: configure parameter information and time-frequency resource allocation information corresponding to at least two types of random access channels; and notify the parameter information and the time-frequency resource allocation information corresponding to the at least two types of random access channels to an access device. The parameter information corresponding to each type of random access channel includes a subcarrier spacing and a preamble sequence, a random access channel bandwidth obtained in accordance with the subcarrier spacing and a length of the preamble sequence is smaller than or equal to a maximum transmission bandwidth of a satellite access device, and the subcarrier spacing includes a reference value of a maximum frequency offset to be resisted by a satellite system.

The program is executed by the processor so as to implement the above-mentioned method for configuring the random access channel at a network device side with a same technical effect, which will not be particularly defined herein.

As shown in <FIG>, the present disclosure further provides in some embodiments a network device, which includes: a configuration module <NUM> configured to configure parameter information and time-frequency resource allocation information corresponding to at least two types of random access channels; and a notification module <NUM> configured to notify the parameter information and the time-frequency resource allocation information corresponding to the at least two types of random access channels to an access device. The parameter information corresponding to each type of random access channel includes a subcarrier spacing and a preamble sequence, a random access channel bandwidth obtained in accordance with the subcarrier spacing and a length of the preamble sequence is smaller than or equal to a maximum transmission bandwidth of a satellite access device, and the subcarrier spacing includes a reference value of a maximum frequency offset to be resisted by a satellite system. In a possible embodiment of the present disclosure, the preamble sequences in the parameter information corresponding to different random access channels have different lengths, and/or the subcarrier spacings in the parameter information corresponding to different random access channels are different.

According to the network device in the embodiments of the present disclosure, the parameter information corresponding to the at least two types of random access channels are configured, and then notified to the access device. Through the parameter information, it is able for the random access channel bandwidth to match a power level of the satellite access device, so as to meet a requirement on a signal-to-noise ratio for the system. In addition, a parameter of the random access channel is selected in such a manner as to approximate to that for a ground <NUM> system, so it is able for a satellite mobile communication system to make full use of an industrial advantages of the ground <NUM> system for development.

The network device in the embodiments of the present disclosure is capable of implementing the above-mentioned method for configuring the random access channel at a network device side with a same technical effect, which will not be particularly defined herein.

It should be appreciated that, in the embodiments of the present disclosure, serial numbers of the steps shall not be used to define the order of the steps, and instead, the order of the steps shall be determined in accordance with their functions and internal logics, which should not constitute any limitation on the embodiments of the present disclosure.

Claim 1:
A method performed by a satellite access device to access a satellite system based on New Radio, NR, access technology, comprising:
obtaining (<NUM>) parameter information and time-frequency resource allocation information corresponding to at least two types of random access channels, the parameter information corresponding to each type of random access channel comprising a subcarrier spacing and a preamble sequence, wherein
a random access channel bandwidth obtained in accordance with the subcarrier spacing and a length of the preamble sequence being smaller than or equal to a maximum transmission bandwidth of the satellite access device, the subcarrier spacing comprising a reference value of a maximum frequency offset to be tolerated by the satellite system;
selecting (<NUM>) target parameter information from the parameter information in accordance with an aperture of the satellite access device, an operating scenario of the satellite access device and a frequency offset proportion of the random access channel; and
selecting (<NUM>) a random access channel in accordance with the target parameter information, and transmitting a random access signal in accordance with the time-frequency resource allocation information.