Random access method and communication apparatus

Abstract

The present application relates to the technical field of communications. Provided are a random access method and a communication apparatus. The method comprises: configuring a plurality of downlink carriers for an RAR and / or a message 4 of the RAR corresponding to a random access resource on each uplink carrier. Therefore, after receiving, on the same uplink carrier and within the same time period, preambles sent by a large number of terminals, an access network device can respectively map to the plurality of downlink carriers, on the basis of the correlation between random access resources of the terminals and the plurality of configured downlink carriers, RARs and / or messages 4 of the RARs replied to the terminals, and send the RARs and / or the messages 4 of the RARs, so as to solve the problem of downlink random access capacity being insufficient in existing NB-IoT systems due to the configuration of only one downlink carrier for an uplink carrier, resulting in insufficient downlink resources to reply to the random access responses (RARs) of all the all terminals and / or the messages 4 of the RARs in a timely manner, thus affecting an uplink capacity expansion effect. The capacity of the NB-IoT systems can be effectively improved.

Description

Random access method and communication device

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on February 8, 2024, with application number 202410178073.3 and invention name “Random Access Method and Communication Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of communications, and in particular to a random access method and a communication device. Background Art

[0003] To increase the uplink coverage capacity of the Internet of Things (IoT) non-terrestrial network (IoT-NTN) system, orthogonal cover codes (OCC) can be used to cover the random access preamble. Based on this, multiple terminals sending random access preambles at the same time-frequency position using different OCCs can be identified by the access network equipment and responded to separately, thereby increasing the uplink random access capacity.

[0004] To reduce the cost and complexity of IoT terminals, the uplink and downlink carrier bandwidths of narrowband IoT (NB-IoT) systems are relatively narrow, both at 180 kHz, resulting in limited resources. The existing protocol stipulates that a preamble sent on an uplink carrier can only be replied to with a random access response (RAR) on a single downlink carrier. Consequently, when using orthogonal cover codes (OCCs) for uplink random access capacity expansion, if the preamble (also known as the preamble sequence) and the orthogonal cover code (OCC) are sent at a high density, the access network equipment will be unable to reply to the RAR on time on the single downlink carrier, thus impacting the uplink capacity expansion. Summary of the Invention

[0005] The embodiments of the present application provide a random access method and a communication device to solve the problem of insufficient downlink capacity in the existing NB-IoT system because only one downlink carrier is configured for one uplink carrier, and therefore there are insufficient downlink resources to reply to the random access response RAR and / or RAR message 4 of all terminals on time.

[0006] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0007] In a first aspect, a random access method is provided, including:

[0008] The terminal receives configuration information from an access network device, where the configuration information includes: multiple uplink carriers, and a correspondence between random access resources of each uplink carrier and multiple downlink carriers; the terminal sends a preamble code to the access network device on the random access resources of a first uplink carrier, where the first uplink carrier is one of the multiple uplink carriers; the terminal selects a downlink carrier from the multiple downlink carriers based on the random access resources of the first uplink carrier and the correspondence; the terminal listens for a random access response RAR and / or RAR message 4 from the access network device on the selected downlink carrier.

[0009] Based on the random access method provided in the first aspect and the second aspect below, multiple downlink carriers can be configured for the RAR and / or RAR message 4 corresponding to the random access resource on each uplink carrier, so that when the access network device receives the preamble codes sent by multiple terminals on the same uplink carrier (such as the first uplink carrier) in the same time period (such as one or more sending cycles), the random access response RAR and RAR / or message 4 replied to each terminal can be mapped to multiple downlink carriers for transmission according to the correspondence between the random access resources of each terminal (such as the preamble code, the orthogonal cover code OCC, and one or more of the sending opportunities) and the configured multiple downlink carriers, so as to solve the problem that the existing NB-IoT system is only configured with one downlink carrier for one uplink carrier, and therefore there are not enough downlink resources to reply to the random access response RAR and / or RAR message 4 of all terminals on time, resulting in insufficient downlink capacity, thereby affecting the uplink expansion effect, and can effectively improve the capacity of the NB-IoT system.

[0010] The random access resources may include one or more of the following: multiple preambles, multiple orthogonal cover codes (OCCs), or multiple transmission opportunities. Accordingly, the corresponding relationship may include one or more of the following: different preambles correspond to different downlink carriers; or different orthogonal cover codes (OCCs) correspond to different downlink carriers; or different transmission opportunities correspond to different downlink carriers. In this way, on the one hand, the access network device can allocate downlink carriers carrying random access response (RAR) and / or RAR messages 4 to a large number of terminals initiating preambles on the same uplink carrier in the same time period based on one or more of the multiple preambles, multiple orthogonal cover codes (OCCs), or multiple transmission opportunities, thereby ensuring sufficient downlink resources to respond to RARs and / or RAR messages 4 from all terminals on time, thereby improving downlink random access capacity. On the other hand, a terminal can also select and monitor the downlink carrier carrying its own RAR based on one or more of the multiple preambles, multiple OCCs, or multiple transmission opportunities, without having to monitor all downlink carriers, thereby improving efficiency.

[0011] In one possible design of the first aspect, the configuration information may further include a first resource configuration mode, where the first resource configuration mode is used to evenly distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier across multiple downlink carriers. In this way, the number of random access response RAR and / or RAR messages 4 can be evenly distributed across multiple downlink carriers, ensuring that a large number of preamble codes initiated on the same uplink carrier in the same time period can be responded to on time, and the workload of each downlink carrier can be balanced.

[0012] Optionally, the downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or transmission timings satisfy the following: downlink carrier index = (preamble code index or orthogonal cover code OCC index or transmission timing index) mod (total number of downlink carriers corresponding to the random access resources of the first uplink carrier), where mod is a modulo operation. In this way, the number of random access responses RAR and / or RAR messages 4 can be evenly distributed among the downlink carriers based on the preamble code index or orthogonal cover code OCC index or transmission timing index of each terminal, and a downlink carrier can be configured for each terminal separately to reduce the workload of each terminal in monitoring the random access response RAR and / or RAR message 4, thereby improving random access efficiency.

[0013] In another possible design of the first aspect, the multiple downlink carriers include a first downlink carrier and at least one second downlink carrier, and the configuration information also includes a second resource configuration method, and the second resource configuration method is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier on the first downlink carrier according to the first weight, and distribute it among at least one second downlink carrier according to the second weight. In this way, the random access response RAR and / or RAR message 4 of a part of the terminals can be preferentially allocated to part of the downlink carriers (such as the first downlink carrier), and the random access response RAR and / or RAR message 4 of the remaining terminals can be evenly distributed among other downlink carriers (such as the second downlink carrier) to ensure that a large number of preamble codes initiated on the same uplink carrier in the same time period can be replied on time, and the workload of each downlink carrier can be balanced.

[0014] Optionally, the first weight may be greater than the second weight. For example, if the channel quality of the first downlink carrier is better than the channel quality of the second downlink carrier, and / or the number of RARs and / or RAR messages 4 allocated to the first downlink carrier is less than the number of RARs and / or RAR messages 4 allocated to the second downlink carrier, more RARs and / or RAR messages 4 are allocated to the first downlink carrier, while fewer are allocated to the second downlink carrier, so as to balance the number of RARs and / or RAR messages 4 carried on each downlink carrier according to the available carrying capacity of each downlink carrier, thereby improving the reliability and efficiency of random access.

[0015] Alternatively, optionally, the first weight may also be smaller than the second weight. For example, if the channel quality of the first downlink carrier is worse than the channel quality of the second downlink carrier, and / or the number of RARs and / or RAR messages 4 allocated to the first downlink carrier is greater than the number of RARs and / or RAR messages 4 allocated to the second downlink carrier, fewer RARs and / or RAR messages 4 are allocated to the first downlink carrier, while more are allocated to the second downlink carrier, so as to balance the number of RARs and / or RAR messages 4 carried on each downlink carrier according to the available carrying capacity of each downlink carrier, thereby improving the reliability and efficiency of random access.

[0016] It should be noted that the number of the first downlink carrier and the number of the second downlink carrier may be one or more, which is not limited in the embodiment of the present invention.

[0017] Optionally, the downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or sending timings satisfy: downlink carrier index = (preamble code index or orthogonal cover code OCC index or sending timing index) mod (weight of the first downlink carrier + sum of weights of at least one second downlink carrier), where mod is a modulo operation. In this way, based on the preamble code index or orthogonal cover code OCC index or sending timing index of each terminal, the random access response RAR and / or RAR message 4 of a part of the terminals can be preferentially allocated to the first downlink carrier, while the random access response RAR and / or RAR message 4 of the remaining terminals can be evenly distributed among other downlink carriers (such as the second downlink carrier) to balance the workload of each downlink carrier, and a downlink carrier can be configured for each terminal separately to reduce the workload of each terminal in monitoring the random access response RAR and / or RAR message 4, thereby improving the random access efficiency.

[0018] In another possible design of the first aspect, the configuration information further includes a third resource configuration mode; the third resource configuration mode is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier among multiple downlink carriers according to their respective weights. In this way, the random access resources of all terminals can be distributed among all downlink carriers according to the weight of each downlink carrier, thereby ensuring that a large number of preamble codes initiated on the same uplink carrier in the same time period can all be responded to on time, and the workload of each downlink carrier can be balanced.

[0019] Optionally, the nth downlink carrier corresponding to different preambles or orthogonal cover codes OCC satisfies the following conditions and has the smallest downlink carrier index: (preamble index or orthogonal cover code OCC index or transmission opportunity index) mod W < W(0) + W(1) + … + W(n); W = W(0) + W(1) + … + W(n) + … + W(Nn - 1); where W is the sum of the weights of multiple downlink carriers, W(n) is the weight of the nth downlink carrier, 0 ≤ n ≤ Nn - 1, and Nn is the number of multiple downlink carriers. In this way, the random access response RAR and / or the number of message 4 of RAR can be allocated among multiple downlink carriers according to the preamble index or orthogonal cover code OCC index or transmission opportunity index of each terminal, and a downlink carrier can be configured for each terminal respectively to reduce the workload of each terminal listening for the random access response RAR and / or message 4 of RAR, thereby improving the random access efficiency.

[0020] In a second aspect, a random access method is provided, including: an access network device sending configuration information, where the configuration information includes: multiple uplink carriers, and the corresponding relationship between the random access resources of each uplink carrier and multiple downlink carriers; the access network device receiving a preamble from a terminal on a first uplink carrier, where the first uplink carrier is one of the multiple uplink carriers; the access network device selecting a downlink carrier from multiple downlink carriers according to the random access resources and the corresponding relationship of the first uplink carrier; the access network device sending a random access response RAR and / or message 4 of RAR to the terminal on the selected downlink carrier.

[0021] Among them, the random access resources may include one or more of the following: multiple preambles, multiple orthogonal cover codes OCC, or multiple transmission opportunities. Correspondingly, the corresponding relationship may include one or more of the following: different preambles correspond to different downlink carriers; or, different orthogonal cover codes OCC correspond to different downlink carriers; or, different transmission opportunities correspond to different downlink carriers.

[0022] In a possible design of the second aspect, the configuration information may further include a first resource configuration method, where the first resource configuration method is used to evenly distribute the random access response RAR and / or message 4 of RAR corresponding to the random access resources of the first uplink carrier among multiple downlink carriers.

[0023] Optionally, the downlink carrier corresponding to different preambles or orthogonal cover codes OCC or transmission opportunities satisfies: the index of the downlink carrier = (preamble index or orthogonal cover code OCC index or transmission opportunity index) mod (the total number of downlink carriers corresponding to the random access resources of the first uplink carrier), and mod is the modulo operation.

[0024] In another possible design of the second aspect, the plurality of downlink carriers include a first downlink carrier and at least one second downlink carrier, and the configuration information further includes a second resource configuration method, where the second resource configuration method is used to allocate the random access response RAR corresponding to the random access resource of the first uplink carrier and / or the message 4 of the RAR on the first downlink carrier according to a first weight, and allocate them among at least one second downlink carrier according to a second weight.

[0025] Optionally, the first weight can be greater than the second weight.

[0026] Alternatively, the first weight can also be less than the second weight.

[0027] Optionally, the downlink carriers corresponding to different preambles or orthogonal cover codes OCC or transmission opportunities satisfy: the index of the downlink carrier = (the index of the preamble or the index of the orthogonal cover code OCC or the index of the transmission opportunity) mod (the weight of the first downlink carrier + the sum of the weights of at least one second downlink carrier), and mod is the modulo operation.

[0028] In another possible design of the second aspect, the configuration information further includes a third resource configuration method; the third resource configuration method is used to allocate the random access response RAR corresponding to the random access resource of the first uplink carrier and / or the message 4 of the RAR among the plurality of downlink carriers according to their respective weights.

[0029] Optionally, the nth downlink carrier corresponding to different preambles or orthogonal cover codes OCC is the downlink carrier that satisfies the following conditions and has the smallest downlink carrier index: (the index of the preamble or the index of the orthogonal cover code OCC or the index of the transmission opportunity) mod W < W(0) + W(1) + … W(n); W = W(0) + W(1) + … W(n) + … + W(Nn - 1); where W is the sum of the weights of the plurality of downlink carriers, W(n) is the weight of the nth downlink carrier, 0 ≤ n ≤ Nn - 1, and Nn is the number of the plurality of downlink carriers.

[0030] In addition, the technical effects of the random access method described in the second aspect can refer to the technical effects of the random access method described in the first aspect, which will not be elaborated here.

[0031] According to a third aspect, a communication device is provided. The device includes: a processing module and a transceiver module; wherein the transceiver module is configured to receive configuration information from an access network device, the configuration information including: multiple uplink carriers and a correspondence between random access resources of each uplink carrier and multiple downlink carriers; the transceiver module is further configured to send a preamble code to the access network device on the random access resources of a first uplink carrier, where the first uplink carrier is one of the multiple uplink carriers; the processing module is configured to select a downlink carrier from the multiple downlink carriers based on the random access resources of the first uplink carrier and the correspondence; and the processing module is further configured to control the transceiver module to monitor a random access response (RAR) and / or RAR message 4 from the access network device on the selected downlink carrier.

[0032] The random access resources may include one or more of the following: multiple preamble codes, multiple orthogonal cover codes (OCCs), or multiple transmission opportunities. Correspondingly, the corresponding relationship may include one or more of the following: different preamble codes correspond to different downlink carriers; or different orthogonal cover codes (OCCs) correspond to different downlink carriers; or different transmission opportunities correspond to different downlink carriers.

[0033] In a possible design of the third aspect, the configuration information may also include a first resource configuration method, which is used to evenly distribute the random access response RAR and / or RAR message 4 corresponding to the random access resources of the first uplink carrier among multiple downlink carriers.

[0034] Optionally, the downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or sending opportunities satisfy: downlink carrier index = (preamble code index or orthogonal cover code OCC index or sending opportunity index) mod (the total number of downlink carriers corresponding to the random access resources of the first uplink carrier), where mod is a modulo operation.

[0035] In another possible design of the third aspect, the multiple downlink carriers include a first downlink carrier and at least one second downlink carrier, and the configuration information also includes a second resource configuration method, and the second resource configuration method is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier on the first downlink carrier according to the first weight, and distribute it according to the second weight between at least one second downlink carrier.

[0036] Optionally, the first weight may be greater than the second weight.

[0037] Alternatively, the first weight may be smaller than the second weight.

[0038] Optionally, the downlink carriers corresponding to different preambles or orthogonal cover codes OCC or transmission opportunities satisfy: the index of the downlink carrier = (preamble index or orthogonal cover code OCC index or transmission opportunity index) mod (weight of the first downlink carrier + sum of the weights of at least one second downlink carrier), where mod is the modulo operation.

[0039] In another possible design of the third aspect, the configuration information further includes a third resource configuration method; the third resource configuration method is used to allocate the random access response RAR corresponding to the random access resources of the first uplink carrier and / or message 4 of the RAR among multiple downlink carriers according to their respective weights.

[0040] Optionally, the nth downlink carrier corresponding to different preambles or orthogonal cover codes OCC satisfies the following conditions and is the downlink carrier with the smallest downlink carrier index: (preamble index or orthogonal cover code OCC index or transmission opportunity index) mod W < W(0) + W(1) + … W(n); W = W(0) + W(1) + … W(n) + … + W(Nn - 1); where W is the sum of the weights of multiple downlink carriers, W(n) is the weight of the nth downlink carrier, 0 ≤ n ≤ Nn - 1, and Nn is the number of multiple downlink carriers.

[0041] The above transceiver module is used to implement the transceiver function. Further, the transceiver module may include a receiving module and a transmitting module. Among them, the transmitting module and the receiving module are respectively used to implement the transmitting function and the receiving function of the communication device described in the fifth aspect.

[0042] Optionally, the communication device described in the third aspect may further include a storage module, which stores programs or instructions. When the processing module executes the program or instruction, the communication device can execute the random access method described in any implementation manner of the first aspect.

[0043] In addition, the technical effects of the communication device described in the third aspect can refer to the technical effects of the random access method described in the first aspect, which will not be elaborated here.

[0044] In the fourth aspect, a communication device is provided. The device includes: a processing module and a transceiver module; among them, the transceiver module is used to send configuration information, and the configuration information includes: multiple uplink carriers, and the corresponding relationship between the random access resources of each uplink carrier and multiple downlink carriers; the transceiver module is further used to receive a preamble from a terminal on the first uplink carrier, and the first uplink carrier is one of the multiple uplink carriers; the processing module is used to select a downlink carrier from multiple downlink carriers according to the random access resources and the corresponding relationship of the first uplink carrier; the transceiver module is further used to send a random access response RAR and / or message 4 of the RAR to the terminal on the selected downlink carrier.

[0045] The random access resources may include one or more of the following: multiple preamble codes, multiple orthogonal cover codes (OCCs), or multiple transmission opportunities. Correspondingly, the corresponding relationship may include one or more of the following: different preamble codes correspond to different downlink carriers; or different orthogonal cover codes (OCCs) correspond to different downlink carriers; or different transmission opportunities correspond to different downlink carriers.

[0046] In a possible design of the fourth aspect, the configuration information may also include a first resource configuration method, which is used to evenly distribute the random access response RAR and / or RAR message 4 corresponding to the random access resources of the first uplink carrier among multiple downlink carriers.

[0047] Optionally, the downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or sending opportunities satisfy: downlink carrier index = (preamble code index or orthogonal cover code OCC index or sending opportunity index) mod (the total number of downlink carriers corresponding to the random access resources of the first uplink carrier), where mod is a modulo operation.

[0048] In another possible design of the fourth aspect, the multiple downlink carriers include a first downlink carrier and at least one second downlink carrier, and the configuration information also includes a second resource configuration method. The second resource configuration method is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier on the first downlink carrier according to the first weight, and distribute it according to the second weight between at least one second downlink carrier.

[0049] Optionally, the first weight may be greater than the second weight.

[0050] Alternatively, the first weight may be smaller than the second weight.

[0051] Optionally, the downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or sending timings satisfy: downlink carrier index = (preamble code index or orthogonal cover code OCC index or sending timing index) mod (weight of the first downlink carrier + sum of weights of at least one second downlink carrier), where mod is a modulo operation.

[0052] In another possible design of the fourth aspect, the configuration information also includes a third resource configuration method; the third resource configuration method is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resources of the first uplink carrier among multiple downlink carriers according to their respective weights.

[0053] Optionally, the nth downlink carrier corresponding to different preambles or orthogonal cover codes OCC satisfies the following conditions and has the smallest downlink carrier index: (preamble index or orthogonal cover code OCC index or transmission occasion index) mod W < W(0) + W(1) + … W(n); W = W(0) + W(1) + … W(n) + … + W(Nn-1); where W is the sum of the weights of multiple downlink carriers, W(n) is the weight of the nth downlink carrier, 0 ≤ n ≤ Nn-1, and Nn is the number of multiple downlink carriers.

[0054] The above transceiver module is used to implement the transceiver function. Further, the transceiver module may include a receiving module and a transmitting module. Among them, the transmitting module and the receiving module are respectively used to implement the transmitting function and the receiving function of the communication device described in the fifth aspect.

[0055] Optionally, the communication device described in the fourth aspect may further include a storage module, and the storage module stores programs or instructions. When the processing module executes the program or instruction, the communication device can execute the random access method described in the second aspect.

[0056] It should be noted that the communication device described in the fourth aspect may be an access network device, such as a base station, or a chip (system) or other components or assemblies that can be set in the access network device, or a device including the access network device. This application does not make any limitations in this regard.

[0057] In addition, the technical effects of the communication device described in the fourth aspect can refer to the technical effects of the random access method described in the first aspect, which will not be elaborated here.

[0058] In a fifth aspect, a communication device is provided. The device includes units or modules for executing any implementation manner described in the first aspect, or includes units or modules for executing any implementation manner described in the second aspect.

[0059] In a possible design of the fifth aspect, the communication device may be the terminal described in the first aspect, such as a mobile phone, or a chip (system) or other components or assemblies that can be set in the terminal, or a device including the terminal device.

[0060] It should be understood that the communication device described in the fifth aspect includes corresponding modules, units, or means for implementing the random access method described in the first aspect above. The module, unit, or means may be implemented by hardware, software, or by hardware executing corresponding software. The hardware or software includes one or more modules or units for executing the functions involved in the above random access method.

[0061] In addition, the technical effects of the communication device described in the fifth aspect can refer to the technical effects of the random access method described in the first aspect, and will not be repeated here.

[0062] In a sixth aspect, a communication device is provided. The device includes: a processor coupled to a memory, the memory being configured to store programs or instructions, wherein when the program or instructions are executed by the processor, the device performs the random access method described in any implementation of the first aspect, or performs the random access method described in any implementation of the second aspect.

[0063] In a possible design of the sixth aspect, the communication device may further include a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be used for the communication device described in the sixth aspect to communicate with other communication devices.

[0064] In the present application, the communication device described in the sixth aspect can be the terminal in the first aspect or the access network device in the second aspect, or a chip (system) or other parts or components that can be set in the terminal or access network device, or a device that includes the terminal or access network device.

[0065] In addition, the technical effects of the communication device described in the sixth aspect can refer to the technical effects of the random access method described in any implementation method of the first aspect, and will not be repeated here.

[0066] In a seventh aspect, a communication system is provided, which includes one or more terminal devices and one or more access network devices.

[0067] In an eighth aspect, a computer-readable storage medium is provided, storing a computer program or instruction. When the computer program or instruction is executed, the computer executes the random access method as described in any one of the implementations in the first aspect, or the random access method as described in any one of the implementations in the second aspect.

[0068] In the ninth aspect, a computer program product is provided, which includes a computer program code. When the computer program code is run on a computer, the computer implements the random access method described in any one of the implementation methods in the first aspect, or implements the random access method described in any one of the implementation methods in the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] FIG1 is a schematic diagram of the structure of a communication system provided in an embodiment of the present application;

[0070] FIG2 is a schematic diagram of a flow chart of a random access method for NB-IoT;

[0071] FIG3 is a schematic diagram of a random access scenario of NB-IoT;

[0072] FIG4 is a schematic diagram of a flow chart of a random access method provided in an embodiment of the present application;

[0073] FIG5 is a schematic diagram of the structure of a communication device provided in an embodiment of the present application;

[0074] FIG6 is a schematic diagram of the structure of a communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0075] The technical solution in this application will be described below with reference to the accompanying drawings.

[0076] The technical solutions of the embodiments of the present application can be applied to various communication systems, such as narrowband Internet of Things (NB-IoT) systems, wireless fidelity (WiFi) systems, vehicle-to-everything (V2X) communication systems, device-to-device (D2D) communication systems, Internet of Vehicles communication systems, 4th generation (4G) mobile communication systems, such as long term evolution (LTE) systems, world-wide interoperability for microwave access (WiMAX) communication systems, fifth generation (5G) mobile communication systems, such as new radio (NR) systems, and future communication systems, such as sixth generation (6G) mobile communication systems.

[0077] This application will present various aspects, embodiments, or features in the context of systems that may include multiple devices, components, modules, etc. It should be understood and appreciated that each system may include additional devices, components, modules, etc., and / or may not include all of the devices, components, modules, etc. discussed in conjunction with the figures. Furthermore, combinations of these aspects may also be used.

[0078] Additionally, in the embodiments of this application, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as an "exemplary" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner.

[0079] In the embodiments of the present application, the terms "information," "signal," "message," "channel," and "signaling" may sometimes be used interchangeably. It should be noted that, when the distinction between them is not emphasized, the meanings they intend to convey are the same. The terms "of," "corresponding," and "corresponding" may sometimes be used interchangeably. It should be noted that, when the distinction between them is not emphasized, the meanings they intend to convey are the same.

[0080] In the embodiments of the present application, sometimes a subscript such as W1 may be mistakenly written as a non-subscript form such as W1. When the difference is not emphasized, the meanings to be expressed are the same.

[0081] The network architecture and business scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Ordinary technicians in this field will know that with the evolution of network architecture and the emergence of new business scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0082] To facilitate understanding of the embodiments of the present application, a communication system applicable to the embodiments of the present application is first described in detail using the communication system shown in Figure 1 as an example. For example, Figure 1 is a schematic diagram of the architecture of a communication system applicable to the communication method provided in the embodiments of the present application.

[0083] As shown in FIG1 , the communication system includes a terminal and access network equipment.

[0084] Among them, the above-mentioned access network device is a device located on the network side of the above-mentioned communication system and has a wireless transceiver function or a chip or chip system that can be set in the device. The access network device includes, but is not limited to, an access point (AP) in a wireless fidelity (WiFi) system, such as a home gateway, a router, a server, a switch, a bridge, etc., an evolved Node B (eNB), a radio network controller (RNC), a Node B (NB), a base station controller (BSC), a base transceiver station (BTS), a home base station (e.g., home evolved NodeB, or home Node B, HNB), a baseband unit (BBU), a wireless relay node, a wireless backhaul node, a transmission and reception point (TRP or transmission point, TP), etc. It can also be 5G, such as a gNB in ​​a new radio (NR) system, or a transmission point (TRP or TP), one or a group of antenna panels (including multiple antenna panels) of a base station in a 5G system, or a network node constituting a gNB or a transmission point, such as a baseband unit (BBU), or a distributed unit (DBU). unit (DU), road side unit (RSU) with base station function, etc.

[0085] The above-mentioned terminal is a terminal device that accesses the above-mentioned communication system and has a wireless transceiver function or a chip (system) or component or assembly that can be set in the terminal device. The terminal can also be called a user device, an access terminal, a user unit, a user station, a mobile station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent or a user device. The terminal device in the embodiment of the present application can be a mobile phone, a tablet computer (Pad), a computer with a wireless transceiver function, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal in industrial control (industrial control), a wireless terminal in self-driving (self driving), a wireless terminal in remote medical (remote medical), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety (transportation safety), a wireless terminal in smart city (smart city), a wireless terminal in smart home (smart home), a vehicle-mounted terminal, an RSU with terminal function, etc.

[0086] It should be noted that the communication method provided in the embodiment of the present application can be applied to the communication between the terminal and the access network device shown in Figure 1. The specific implementation can refer to the following method embodiment, which will not be repeated here.

[0087] It should be noted that the solutions in the embodiments of the present application can also be applied to other communication systems, and the corresponding names can also be replaced by the names of corresponding functions in other communication systems.

[0088] It should be understood that FIG1 is only a simplified schematic diagram for ease of understanding, and the communication system may also include other network devices and / or other terminal devices, which are not shown in FIG1 .

[0089] First, random access related technologies are introduced with reference to FIG. 2 and FIG. 3 .

[0090] For example, Figure 2 is a flowchart of a random access method for NB-IoT. As shown in Figure 2, the random access process is a necessary process for a terminal to access a cell, and has many functions, such as sending uplink services, responding to network paging, etc. When the terminal initiates the random access process, it first selects the corresponding random access time and frequency resources and the corresponding preamble (also called preamble sequence) according to the system broadcast configuration, and then executes the steps shown in Figure 2:

[0091] S201: The terminal sends a selected preamble code on a selected time-frequency resource.

[0092] The preamble primarily notifies the access network equipment that a terminal needs to access the network. To increase uplink random access capacity, the random access in Rel-19's IoT-NTN introduces orthogonal cover codes (OCCs), which are superimposed on the preamble for transmission.

[0093] S202: The access network device sends a random access response (RAR) to the terminal in response to the received preamble.

[0094] The RAR may include responses to different preambles sent at the same time-frequency location. Each preamble response may include instructions for sending the next message, such as uplink resources for message 3 (Msg 3), uplink timing adjustment commands for the terminal, and temporary cell identifiers, such as the temporary cell-radio network temporary identifier (TC-RNTI).

[0095] S203: The terminal sends message 3 to the access network device.

[0096] Specifically, the terminal can use the random access radio network temporary identifier (RA-RNTI) determined based on the time-frequency resources used to send the preamble to decode the physical downlink control channel (PDCCH) to obtain the scheduling information of the RAR, and then receive the RAR sent on the physical downlink shared channel (PDSCH) based on the scheduling information. If there is a response to the preamble selected by the terminal in the RAR, the uplink timing is adjusted and the corresponding uplink resources are used to send Msg3, which contains the terminal's identifier, such as S-TMSI, TC-RNTI, etc.

[0097] S204, the access network device sends message 4 (Msg4) to the terminal.

[0098] Specifically, after receiving Msg3 containing the terminal's TC-RNTI, if the terminal is allowed to access, the access network device replies to the terminal in Msg4, indicating that the terminal contention has been successfully resolved and the terminal has access to the network. At this point, the terminal's TC-RNTI is upgraded to (cell-radio network temporary identifier, C-RNTI), and the C-RNTI is used for subsequent data and signaling transmission and reception in the cell.

[0099] In the above random access process, the terminal first needs to select time-frequency resources according to the system broadcast configuration and select the corresponding preamble to send to the base station. In the NB-IoT system, the configuration of random access resources and terminal selection generally include the following granularity:

[0100] Granularity 1, uplink carrier selection (UL Carrier, each 180 kHz bandwidth): A cell may have random access resources on multiple uplink carriers, including random access time resources, preamble resources, and downlink carriers for receiving RARs. Each random access resource may correspond to a different coverage level, and preambles sent on different uplink carriers may correspond to the same downlink carrier for receiving RARs. Based on its measured coverage level, the terminal randomly selects an uplink carrier configured with random access resources corresponding to its coverage level.

[0101] Granularity 2, preamble selection: After selecting an uplink carrier, the terminal randomly selects a preamble from the random access resources corresponding to its own coverage level on the uplink carrier. In the long term evolution (LTE) system or the new radio (NR) system, the randomly accessed uplink carrier is a ZC sequence, and different uplink carriers correspond to different sequences. However, in the NB-IoT system, there is only one all-1 sequence available. According to the protocol, the terminal selects the uplink carrier, which is actually the selection of the subcarrier (subcarrier) to send the uplink carrier, which is still a frequency selection operation. That is, the index or ID of an uplink carrier does not correspond to a sequence, but to the index or ID of a subcarrier.

[0102] Granularity 3, selecting the transmission opportunity: After selecting the UL carrier, the terminal initiates random access at the allowed transmission opportunity in the random access resources corresponding to its own coverage level on the carrier according to the transmission opportunity configuration (period, starting position, etc.).

[0103] For example, Figure 3 is a schematic diagram of a random access scenario for NB-IoT. As shown in Figure 3, two terminals (terminal 1 and terminal 2) select different uplink carriers but receive RAR on the same downlink carrier, as follows:

[0104] Terminal 1: selects uplink carrier 1 and subcarrier 2 (preamble 2), and sends the preamble at transmission timing x.

[0105] Terminal 2: selects uplink carrier 2 and subcarrier 1 (preamble 1), and also sends the preamble at sending timing x.

[0106] Assume that uplink carrier 1 and uplink carrier 2 are both associated with the same downlink carrier. That is, terminals that send preamble codes on these two uplink carriers, such as terminal 1 and terminal 2 mentioned above, need to monitor the RAR on downlink carrier 1.

[0107] After receiving two preambles, the access network device will try to reply on downlink carrier 1. According to the protocol, the PDCCH scheduling RAR is scrambled using RA-RNTI, RA-RNTI = 1 + floor (SFN_id / 4) + 256 * carrier_id.

[0108] floor(SFN_id / 4) is time-related information, that is, the system frame number SFN / 4 for sending the preamble. Terminal 1 and Terminal 2 send the preamble at the same time, so Terminal 1 and Terminal 2 have the same information.

[0109] 256*carrier_id is the uplink carrier information. Since terminal 1 and terminal 2 select different uplink carriers, this part of information is different.

[0110] Therefore, since the RA-RNTIs of terminal 1 and terminal 2 are different, the access network device can schedule and reply respectively.

[0111] Assume that there is also terminal 3: uplink carrier 1 and subcarrier (preamble code) 4 are selected, and the preamble code is also sent at transmission opportunity x. Since the RA-RNTI of terminal 1 and terminal 3 is the same, different replies cannot be scheduled using different RA-RNTIs. That is, the replies of terminal 1 and terminal 3 will be multiplexed in the same RAR. However, in a RAR, different replies will indicate different preamble code identifiers, and each reply will be associated with a RAPID (random access preamble ID).

[0112] As described above, after sending the preamble, the terminal uses the RA-RNTI generated from the sent time-frequency information to decode the PDCCH and then receives the RAR. Only when the terminal decodes the PDCCH and the RAR contains its own preamble ID does the terminal consider itself to have received a reply.

[0113] Furthermore, OCC can be introduced in random access, so that different preamble codes can be sent on the same time-frequency resources to further superimpose code domain information and increase the transmission capacity of the preamble code. However, since the uplink and downlink carriers of the NB-IoT system are relatively narrow (both 180khz), the capacity may be limited. According to the existing protocol, the preamble code sent on an uplink carrier can only be replied to the random access response on a downlink carrier. In the case of uplink capacity expansion, the downlink reply capacity is likely to be insufficient.

[0114] Currently, an NB-IoT cell includes:

[0115] Required: Anchor carrier, including system broadcast and synchronization signals, as well as narrow-band physical random access channel (NPRACH) resources;

[0116] Optional: Up to 15 non-anchor carriers, each containing NPRACH resources.

[0117] The NPRACH transmission period is 40-2560ms;

[0118] The transmission time of the downlink PDCCH+PDSCH combination, that is, the shortest time to reply to a RAR MAC CE, Rmax*offset, minimum 4ms;

[0119] At the same NPRACH transmission opportunity, the maximum number of preamble codes (subcarriers) that can be transmitted is 48 (SCS=15kHz) or 144 (SCS=3.75kHz), where SCS is the subcarrier spacing.

[0120] The following calculates the downlink capacity based on the above parameters.

[0121] As shown in Table 1, when one NPRACH uplink carrier is mapped to one downlink carrier:

[0122] Assuming that the maximum number of preambles that a MAC CE can reply is 12 = floor (680 bits / 56 bits), and the minimum time for scheduling and transmitting a downlink transport block (TB) is 4 ms, then:

[0123] When OCC is not introduced, it is likely that it will take enough time to reply RAR on one downlink carrier (16ms-48ms). Among them, when the SCS is 15kHz, the number of preamble codes supported by one uplink carrier is 48, and the minimum response time required for all RARs = 4ms*(48 / 12) = 4ms*4 = 16ms, which is less than the shortest transmission period of 40ms, and all RARs can be replied within one shortest transmission period (40ms). However, when the SCS is 3.75kHz, the number of preamble codes supported by one uplink carrier is 144, and the minimum response time required for all RARs = 4ms*(144 / 12) = 4ms*12 = 48ms, which is greater than the shortest transmission period of 40ms, and therefore it is impossible to reply all RARs within one shortest transmission period (40ms), that is, some RARs cannot be replied on time. In other words, without the introduction of OCC, that is, without uplink capacity expansion, the NB-IoT system may not be able to reply to all RARs on time within the shortest transmission cycle, posing a risk of insufficient downlink capacity.

[0124] However, when OCC is introduced, the uplink preamble and OCC transmission density increases, resulting in insufficient resources on a single downlink carrier to send the RAR on time, thus impacting uplink capacity expansion. For example, with OCC number y = 4, the time required to reply to the RAR on a single downlink carrier (64ms to 192ms) is significantly longer than the minimum transmission period (40ms).

[0125] When the SCS is 15kHz, the number of preambles supported by one uplink carrier is 48, and the minimum response time required for all RARs is 4ms*(48*4 / 12)=4ms*16=64ms. When the SCS is 3.75kHz, the number of preambles supported by one uplink carrier is 144, and the minimum response time required for all RARs is 4ms*(144*4 / 12)=4ms*48=192ms. Both are much longer than the minimum transmission period of 40ms, and the access network equipment cannot respond to all RARs within the minimum transmission period (40ms). In other words, after the introduction of OCC, the number of RARs that need to be responded to within a transmission period increases exponentially, making the downlink capacity shortage problem more serious. Therefore, how to further improve the random access downlink capacity to ensure that all RARs (differentiated by preambles and OCC) can respond on time has become a technical problem that needs to be solved urgently.

[0126] Table 1

[0127] To solve the above-mentioned problem of insufficient downlink random access capacity, an embodiment of the present invention provides a random access method, which introduces the following mechanism: one uplink carrier corresponds to multiple downlink carriers. When the terminal sends a preamble code (an orthogonal cover code OCC can be superimposed), the access network device can distribute all RARs to be replied evenly among multiple downlink carriers based on the random access resources for sending preamble codes by all terminals. Correspondingly, the terminal can also select one from the multiple downlink carriers to monitor its own RAR based on the random access resources for sending preamble codes, thereby ensuring that all preamble codes on the same uplink carrier in the same time period can be replied on time within one sending cycle, thereby improving the uplink and downlink capacity of the NB-IoT system.

[0128] The random access method provided in the embodiment of the present application will be described in detail below with reference to FIG4 .

[0129] For example, FIG4 is a flow chart of a random access method provided in an embodiment of the present application. The random access method can be applied to the communication system shown in FIG1. ​​As shown in FIG4, the method includes the following steps:

[0130] S401: The access network device sends configuration information, and the terminal receives the configuration information from the access network device.

[0131] The configuration information includes: multiple uplink carriers, and a correspondence between random access resources of each uplink carrier and multiple downlink carriers.

[0132] Each uplink carrier may be configured with multiple corresponding downlink carriers, and the multiple downlink carriers may include one anchor carrier and one or more non-anchor carriers.

[0133] S402: The terminal sends a preamble to the access network device on a random access resource of a first uplink carrier, and the access network device receives the preamble from the terminal on the first uplink carrier.

[0134] The first uplink carrier is one of a plurality of uplink carriers. For example, the terminal may randomly select one of the plurality of configured uplink carriers to send the preamble code.

[0135] It should be noted that different terminals may select the same uplink carrier and send their own preambles to the same access network device at the same transmission time. The preamble sent by each terminal can be randomly selected by the terminal from the configured preambles. In other words, different terminals may send the same preamble.

[0136] S403: The terminal and the access network device select a downlink carrier from multiple downlink carriers according to the random access resource and the corresponding relationship of the first uplink carrier.

[0137] When an access network device receives preambles sent by multiple terminals on the same uplink carrier during the same time period (e.g., one or more transmission cycles), the access network device can respond to the RARs, Message 4, etc. of each terminal on the multiple downlink carriers based on the random access resources used by each terminal. Correspondingly, each terminal can select the downlink carrier carrying its own RAR from the multiple downlink carriers and monitor it according to the same rules.

[0138] S404: The access network device sends a random access response RAR and / or RAR message 4 to the terminal on the selected downlink carrier. The terminal monitors the random access response RAR and / or RAR message 4 from the access network device on the selected downlink carrier.

[0139] The random access resources may include one or more of the following: multiple preambles, multiple orthogonal cover codes (OCCs), or multiple transmission opportunities. Accordingly, the corresponding relationship may include one or more of the following:

[0140] Corresponding to mode 1, different preamble codes correspond to different downlink carriers; or,

[0141] Corresponding to mode 2, different orthogonal cover codes OCC correspond to different downlink carriers; or,

[0142] Corresponding to mode 3, different sending timings correspond to different downlink carriers.

[0143] In other words, when different terminals want to access the network, they can be distinguished by one or more of the preamble codes, orthogonal cover codes OCC, and sending timings sent by different terminals. As long as at least one of the preamble codes, orthogonal cover codes OCC, and sending timings sent by each terminal is different, the access network equipment can distinguish different terminals.

[0144] In this way, on the one hand, the access network device can determine the downlink carrier carrying the random access response RAR and / or RAR message 4 for a large number of terminals requesting network access using the same uplink carrier in the same time period based on one or more of multiple preambles, multiple OCCs, or multiple transmission opportunities, thereby ensuring sufficient downlink resources to reply to the random access response RAR and / or RAR message 4 of all terminals on time, thereby improving downlink random access capacity. On the other hand, the terminal can also select and monitor the downlink carrier carrying its own random access response RAR and / or RAR message 4 based on one or more of multiple preambles, multiple OCCs, or multiple transmission opportunities, without having to monitor all downlink carriers, thereby improving random access efficiency.

[0145] For the above corresponding manner 1 and corresponding manner 2, the following first resource configuration manner, second resource configuration manner, and third resource configuration manner may be used to select a downlink carrier, which will be described in detail below.

[0146] In one possible design, the configuration information may further include a first resource configuration method, where the first resource configuration method is used to evenly distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier among multiple downlink carriers. In this way, the number of random access response RAR and / or RAR messages 4 can be evenly distributed (as much as possible) across multiple downlink carriers to ensure that a large number of terminals requesting network access on the same uplink carrier in the same time period can receive responses on time and the workload of each downlink carrier can be balanced.

[0147] Optionally, the downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or transmission timings satisfy the following: downlink carrier index = (preamble code index or orthogonal cover code OCC index or transmission timing index) mod (total number of downlink carriers corresponding to the random access resources of the first uplink carrier), where mod is a modulo operation. In this way, the number of random access responses RAR and / or RAR messages 4 can be evenly distributed among the downlink carriers based on the preamble code index or orthogonal cover code OCC index or transmission timing index of each terminal, and a downlink carrier can be configured for each terminal separately to reduce the workload of each terminal in monitoring the random access response RAR and / or RAR message 4, thereby improving random access efficiency.

[0148] For example, assuming that five downlink carriers (CC1-CC5) are configured, each CC needs to carry 1 / 5=20% of the RAR.

[0149] In another possible design, the multiple downlink carriers include a first downlink carrier and at least one second downlink carrier, and the configuration information also includes a second resource configuration method, and the second resource configuration method is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier on the first downlink carrier according to the first weight, and distribute it among at least one second downlink carrier according to the second weight. In this way, the random access response RAR and / or RAR message 4 of a part of the terminals can be preferentially allocated to part of the downlink carriers (such as the first downlink carrier), and the random access response RAR and / or RAR message 4 of the remaining terminals can be evenly distributed among other downlink carriers (such as the second downlink carrier) to ensure that a large number of terminals requesting access to the network on the same uplink carrier in the same time period can reply to the random access response RAR and / or RAR message 4 on time, and the workload of each downlink carrier can be balanced.

[0150] Optionally, the first weight may be greater than the second weight. For example, if the channel quality of the first downlink carrier is better than the channel quality of the second downlink carrier, and / or the number of RARs and / or RAR messages 4 allocated to the first downlink carrier is less than the number of RARs and / or RAR messages 4 allocated to the second downlink carrier, more RARs and / or RAR messages 4 are allocated to the first downlink carrier, while fewer are allocated to the second downlink carrier, so as to balance the number of RARs and / or RAR messages 4 carried on each downlink carrier according to the available carrying capacity of each downlink carrier, thereby improving the reliability and efficiency of random access.

[0151] Alternatively, optionally, the first weight may also be smaller than the second weight. For example, if the channel quality of the first downlink carrier is worse than the channel quality of the second downlink carrier, and / or the number of RARs and / or RAR messages 4 allocated to the first downlink carrier is greater than the number of RARs and / or RAR messages 4 allocated to the second downlink carrier, fewer RARs and / or RAR messages 4 are allocated to the first downlink carrier, while more are allocated to the second downlink carrier, so as to balance the number of RARs and / or RAR messages 4 carried on each downlink carrier according to the available carrying capacity of each downlink carrier, thereby improving the reliability and efficiency of random access.

[0152] That is to say, downlink carriers with better channel quality or stronger carrying capacity can carry more RAR and / or RAR message 4, while downlink carriers with poorer channel quality or weaker carrying capacity can carry less or no RAR and / or RAR message 4, so as to maximize transmission reliability and random access efficiency.

[0153] It should be noted that the first downlink carrier may be an existing downlink carrier, and the number of the second downlink carriers may be one or more, which is not limited in the embodiment of the present invention.

[0154] Optionally, the downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or sending timings satisfy: downlink carrier index = (preamble code index or orthogonal cover code OCC index or sending timing index) mod (weight of the first downlink carrier + sum of weights of at least one second downlink carrier), where mod is a modulo operation. In this way, based on the preamble code index or orthogonal cover code OCC index or sending timing index of each terminal, the random access response RAR and / or RAR message 4 of a part of the terminals can be preferentially allocated to the first downlink carrier, while the random access response RAR and / or RAR message 4 of the remaining terminals can be evenly distributed among other downlink carriers (such as the second downlink carrier) to balance the workload of each downlink carrier, and a downlink carrier can be configured for each terminal separately to reduce the workload of each terminal in monitoring the random access response RAR and / or RAR message 4, thereby improving the random access efficiency.

[0155] For example, assume that one first downlink carrier (CC1) and three second downlink carriers (CC2 - CC4) are configured, and the weight of CC1 is 2. Then CC1 carries 2 / (2 + 3) = 40% of the RAR and / or Message 4 of the RAR, while each of CC2 - CC4 carries 1 / (2 + 3) = 20% of the RAR and / or Message 4 of the RAR.

[0156] In another possible design of the embodiment of the present invention, the configuration information further includes a third resource configuration method; the third resource configuration method is used to allocate the random access response RAR and / or Message 4 corresponding to the random access resources of the first uplink carrier among multiple downlink carriers according to their respective weights. In this way, the random access resources of all terminals can be allocated among all downlink carriers according to the weights of the downlink carriers, so as to ensure that a large number of terminals requesting to access the network on the same uplink carrier in the same time period can reply to their respective random access responses RAR and / or Message 4 on time, and the workload of each downlink carrier can be balanced.

[0157] Optionally, the nth downlink carrier corresponding to different preambles or orthogonal cover codes OCC satisfies the following conditions, and is the downlink carrier with the smallest downlink carrier index: (preamble index or orthogonal cover code OCC index or transmission occasion index) mod W < W(0) + W(1) + … W(n); W = W(0) + W(1) + … W(n) + … + W(Nn - 1); where W is the sum of the weights of multiple downlink carriers, W(n) is the weight of the nth downlink carrier, 0 ≤ n ≤ Nn - 1, and Nn is the number of multiple downlink carriers. In this way, the number of random access responses RAR and / or Message 4 of the RAR can be allocated among the downlink carriers according to the preamble index or orthogonal cover code OCC index or transmission occasion index of each terminal, and the downlink carriers can be configured for each terminal respectively, so as to reduce the workload of each terminal for listening to the random access response RAR and / or Message 4 of the RAR, thereby improving the random access efficiency.

[0158] For example, assume that there are five downlink carriers CC1 - CC5 configured, and the weights of CC1 - CC5 are in sequence: 1, 2, 4, 2, 1. Then CC1 and CC5 carry 1 / (1 + 2 + 4 + 2 + 1) = 10% of the RAR and / or Message 4 of the RAR, CC2 and CC4 carry 2 / (1 + 2 + 4 + 2 + 1) = 20% of the RAR, and CC3 carries 4 / (1 + 2 + 4 + 2 + 1) = 40% of the RAR and / or Message 4 of the RAR.

[0159] It should be noted that the above-mentioned preamble code index or OCC index is an index in the preamble code list or OCC list configured by the system or actually selectable by the terminal. For example, if a cell is configured with 48 preamble codes, the first preamble code index is 0 (or 1), the second preamble code index is 1 (or 2), and so on, the 48th preamble code index is 47 (or 48). The system can configure different available preamble codes or orthogonal cover codes OCC or transmission timing for each uplink carrier and each repetition number (different repetition numbers achieve different coverage). The terminal can generate the corresponding index based on all available preamble codes or OCCs in the system, or based on the range of available preamble codes or OCCs for the uplink carrier and / or repetition number that it can actually select. For example, if a total of 48 carriers are available in the system, the repetition number of uplink carriers used by the terminal can only use indexes 13-24. If the terminal can select the 13th, the index can be 12 (corresponding to all 48 indexes numbered starting from 0) or 13 (corresponding to all 48 indexes numbered starting from 1). Alternatively, the index can also be 0 (corresponding to renumbering from 0 within the range of indexes selectable by the terminal) or 1 (corresponding to renumbering from 1 within the range of indexes selectable by the terminal). The index generation method can be indicated by the access network device configuration or agreed upon by protocol. As long as the terminal and the access network device are consistent, the downlink carrier selection results will be consistent.

[0160] The sending timing index may be one or any combination of the (first) system superframe number, system frame number, system subframe number, or random access period index for sending the preamble. Since the time resources available for random access are generally periodic, the random access period index refers to the random access period in which the preamble is sent, and may be the (first) system superframe number, system frame number, or system subframe number divided by the random access period, optionally rounded down. The random access period may be a random access resource period configured by the system, a random access resource period selected by the terminal, or the maximum or minimum random access resource period specified by the protocol, etc., and is not limited in the embodiments of the present invention.

[0161] The first and second configurations described above can both be considered special cases of the third configuration. For example, if, in the third configuration, the weights of all downlink carriers are equal, this is the first configuration. For another example, if, in the third configuration, the weights of some downlink carriers are greater than 1 and the weights of other downlink carriers are 1, this is the second configuration.

[0162] It should be noted that, in addition to the first to third configuration modes described above, the access network device may also configure a corresponding downlink carrier for each random access resource on an uplink carrier, for monitoring the RAR and / or RAR Message 4 corresponding to the random access resource. In this way, if a terminal sends a preamble on a random access resource on an uplink carrier and the preamble is received by the access network device, both the terminal and the access network device can directly query the downlink carrier for monitoring / sending the RAR and / or RAR Message 4 corresponding to the random access resource based on the random access resource on the uplink carrier, eliminating the need for calculations as in the first to third configuration modes described above, thereby reducing computational workload.

[0163] For example, the access network device can explicitly indicate the correspondence between each preamble code and the downlink carrier through signaling, as shown below: preamble codes 1 and 2 correspond to downlink carrier 1, and preamble codes 3 and 4 correspond to downlink carrier 2. For another example, the access network device can also explicitly indicate the correspondence between each orthogonal cover code OCC and the downlink carrier through signaling, as shown below: orthogonal cover codes OCC1 and 3 correspond to downlink carrier 1, and orthogonal cover codes OCC2 and 4 correspond to downlink carrier 2.

[0164] The above is only how the access network device explicitly configures the correspondence between the random access resource of a specific dimension and the downlink carrier through signaling, so that both the access network device and the terminal can uniquely determine the downlink carrier for sending / receiving RAR and / or RAR message 4 through the random access resource used by the terminal to send the preamble. The specific resource dimensions indicated are not limited to the above two.

[0165] In addition, the number of downlink carriers required can be estimated based on the configured number of orthogonal cover codes (OCCs), preambles, and transmission opportunities. Specifically, the total number of RARs required for a transmission cycle = the number of orthogonal cover codes (OCCs) * the number of preambles * the number of transmission opportunities. This represents the maximum number of preambles that can be received in a transmission cycle, and therefore the maximum number of terminals or users.

[0166] For example, referring to Table 1, according to SCS = 3.75kHz (i.e., the number of preambles supported by one uplink carrier = 144), the minimum transmission period (40ms), the maximum number of preambles that one MAC CE can reply to is 12, the shortest time for scheduling and transmitting one downlink TB is 4ms, the total number of orthogonal cover codes OCC = 8, the number of preambles = 144, and the number of transmission opportunities = 8. Then, the total number of RARs that need to be replied in one transmission period = 8*144*8, and the required number of downlink carriers M satisfies:

[0167] 4ms*8*144*8 / (12*M)≤40ms, that is, M≥ceil[(4*8*144*8) / (12*40)]=77.

[0168] Based on the random access method provided in an embodiment of the present invention, multiple downlink carriers can be configured for the RAR and / or RAR message 4 corresponding to the random access resource on each uplink carrier, so that when the access network device receives the preamble codes sent by multiple terminals on the same uplink carrier (such as the first uplink carrier) in the same time period (such as one or more sending cycles), the random access response RAR and RAR / or message 4 replied to each terminal can be mapped to multiple downlink carriers for transmission according to the correspondence between the random access resources (such as preamble code, orthogonal cover code OCC, and sending timing) of each terminal and the configured multiple downlink carriers, so as to solve the problem that the existing NB-IoT system is only configured with one downlink carrier for one uplink carrier, and therefore there are not enough downlink resources to reply to the random access response RAR and / or RAR message 4 of all terminals on time, resulting in insufficient downlink capacity, thereby affecting the uplink expansion effect, and can effectively improve the capacity of the NB-IoT system.

[0169] The random access method provided in the embodiment of the present application is described in detail above in conjunction with Figure 4. The following describes in detail a communication device for executing the random access method provided in the embodiment of the present application in conjunction with Figures 5-6.

[0170] An embodiment of the present invention further provides a communication device, which includes a unit or module for executing a terminal function or an access network function in the random access method provided in the above method embodiment.

[0171] In one possible design, the communication device can be the terminal described in the above method embodiment, such as a mobile phone, or a chip (system) or other parts or components that can be set in the terminal, or a device or equipment that includes the terminal device.

[0172] It should be understood that the communication device may include modules, units, or means corresponding to the random access method described in the above method embodiment. The modules, units, or means may be implemented through hardware, software, or hardware executing corresponding software implementations. The hardware or software includes one or more modules or units for performing the functions involved in the above random access method.

[0173] For example, Figure 5 is a structural diagram of a communication device according to an embodiment of the present application. As shown in Figure 5 , the communication device 500 includes a processing module 501 and a transceiver module 502. For ease of illustration, Figure 5 only shows the main components of the communication device.

[0174] In some embodiments, the communication device 500 may be applicable to the communication system shown in FIG. 1 , and perform the function of a terminal in the random access method shown in FIG. 4 .

[0175] The transceiver module 502 is configured to receive configuration information from an access network device, the configuration information including: multiple uplink carriers, and a correspondence between random access resources of each uplink carrier and multiple downlink carriers;

[0176] The transceiver module 502 is further configured to send a preamble code to the access network device on a random access resource of a first uplink carrier, where the first uplink carrier is one of the multiple uplink carriers;

[0177] The processing module 501 is configured to select a downlink carrier from multiple downlink carriers according to the random access resource of the first uplink carrier and the corresponding relationship;

[0178] The processing module 501 is further configured to control the transceiver module 502 to monitor the random access response RAR and / or RAR message 4 from the access network device on the selected downlink carrier.

[0179] The random access resources may include one or more of the following: multiple preamble codes, multiple orthogonal cover codes (OCCs), or multiple transmission opportunities. Correspondingly, the corresponding relationship may include one or more of the following: different preamble codes correspond to different downlink carriers; or different orthogonal cover codes (OCCs) correspond to different downlink carriers; or different transmission opportunities correspond to different downlink carriers.

[0180] In a possible design of an embodiment of the present invention, the configuration information may also include a first resource configuration method, which is used to evenly distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier among multiple downlink carriers.

[0181] Optionally, the downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or sending opportunities satisfy: downlink carrier index = (preamble code index or orthogonal cover code OCC index or sending opportunity index) mod (the total number of downlink carriers corresponding to the random access resources of the first uplink carrier), where mod is a modulo operation.

[0182] In another possible design of an embodiment of the present invention, the multiple downlink carriers include a first downlink carrier and at least one second downlink carrier, and the configuration information also includes a second resource configuration method. The second resource configuration method is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier on the first downlink carrier according to the first weight, and distribute it according to the second weight between at least one second downlink carrier.

[0183] Optionally, the first weight may be greater than the second weight.

[0184] Alternatively, the first weight may be smaller than the second weight.

[0185] Optionally, the downlink carriers corresponding to different preambles or orthogonal cover codes OCCs or transmission opportunities satisfy: the index of the downlink carrier = (the preamble index or the orthogonal cover code OCC index or the transmission opportunity index) mod (the weight of the first downlink carrier + the sum of the weights of at least one second downlink carrier), where mod is the modulo operation.

[0186] In another possible design of the embodiment of the present invention, the configuration information further includes a third resource configuration method; the third resource configuration method is used to allocate the random access response RAR corresponding to the random access resources of the first uplink carrier and / or message 4 of the RAR among multiple downlink carriers according to their respective weights.

[0187] Optionally, the nth downlink carrier corresponding to different preambles or orthogonal cover codes OCCs is the downlink carrier that satisfies the following conditions and has the smallest downlink carrier index: (the preamble index or the orthogonal cover code OCC index or the transmission opportunity index) mod W < W(0) + W(1) + … W(n); W = W(0) + W(1) + … W(n) + … + W(Nn-1); where W is the sum of the weights of multiple downlink carriers, W(n) is the weight of the nth downlink carrier, 0 ≤ n ≤ Nn-1, and Nn is the number of multiple downlink carriers.

[0188] The above communication device 500 may be a terminal, or a chip (system) or other components or assemblies that can be set in the terminal, or a device or equipment including the terminal. The present application does not limit this.

[0189] In some other embodiments, the communication device 500 may be applicable to the communication system shown in FIG. 1 and perform the function of the access network device in the random access method shown in FIG. 4.

[0190] Among them, the transceiver module 502 is used to send configuration information, and the configuration information includes: multiple uplink carriers, and the corresponding relationship between the random access resources of each uplink carrier and multiple downlink carriers;

[0191] The transceiver module 502 is further used to receive a preamble from the terminal on the first uplink carrier, and the first uplink carrier is one of the multiple uplink carriers;

[0192] The processing module 501 is used to select a downlink carrier from multiple downlink carriers according to the random access resources of the first uplink carrier and the corresponding relationship;

[0193] The transceiver module 502 is further used to send a random access response RAR and / or message 4 of the RAR to the terminal on the selected downlink carrier.

[0194] The random access resources may include one or more of the following: multiple preamble codes, multiple orthogonal cover codes (OCCs), or multiple transmission opportunities. Correspondingly, the corresponding relationship may include one or more of the following: different preamble codes correspond to different downlink carriers; or different orthogonal cover codes (OCCs) correspond to different downlink carriers; or different transmission opportunities correspond to different downlink carriers.

[0195] In a possible design of an embodiment of the present invention, the configuration information may also include a first resource configuration method, which is used to evenly distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier among multiple downlink carriers.

[0196] Optionally, the downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or sending opportunities satisfy: downlink carrier index = (preamble code index or orthogonal cover code OCC index or sending opportunity index) mod (the total number of downlink carriers corresponding to the random access resources of the first uplink carrier), where mod is a modulo operation.

[0197] In another possible design of an embodiment of the present invention, the multiple downlink carriers include a first downlink carrier and at least one second downlink carrier, and the configuration information also includes a second resource configuration method. The second resource configuration method is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier on the first downlink carrier according to the first weight, and distribute it according to the second weight between at least one second downlink carrier.

[0198] Optionally, the first weight may be greater than the second weight.

[0199] Alternatively, the first weight may be smaller than the second weight.

[0200] Optionally, the downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or sending timings satisfy: downlink carrier index = (preamble code index or orthogonal cover code OCC index or sending timing index) mod (weight of the first downlink carrier + sum of weights of at least one second downlink carrier), where mod is a modulo operation.

[0201] In another possible design of an embodiment of the present invention, the configuration information also includes a third resource configuration method; the third resource configuration method is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier among multiple downlink carriers according to their respective weights.

[0202] Optionally, the nth downlink carrier corresponding to different preambles or orthogonal cover codes OCCs satisfies the following conditions and has the smallest downlink carrier index: (preamble index or orthogonal cover code OCC index or transmission occasion index) mod W < W(0) + W(1) + … W(n); W = W(0) + W(1) + … W(n) + … + W(Nn-1); where W is the sum of the weights of multiple downlink carriers, W(n) is the weight of the nth downlink carrier, 0 ≤ n ≤ Nn-1, and Nn is the number of multiple downlink carriers.

[0203] The communication device 500 may be an access network device, such as a base station, or a chip (system) or other component or assembly that can be set in the access network device, or may also be a device or equipment including the access network device. The present application does not limit this.

[0204] It should be noted that the above transceiver module 502 is used to implement the transceiver function. Further, the transceiver module 502 may include a receiving module and a transmitting module. Among them, the transmitting module and the receiving module are respectively used to implement the transmitting function and the receiving function of the communication device 500.

[0205] Optionally, the communication device 500 may further include a storage module that stores programs or instructions. When the processing module 501 executes the program or instruction, the communication device 500 can execute the random access method provided in the above method embodiment.

[0206] In addition, the technical effects of the communication device 500 can refer to the technical effects of the random access method provided in the above method embodiment, which will not be elaborated here.

[0207] Exemplarily, FIG. 6 is a second schematic structural diagram of the communication device provided in the embodiment of the present application. The communication device may be a terminal device or an access network device, or may also be a chip (system) or other component or assembly that can be set in the terminal device or the access network device. As shown in FIG. 6, the communication device 600 may include a processor 601. Optionally, the communication device 600 may further include a memory 602 and / or a transceiver 603. Among them, the processor 601 is coupled to the memory 602 and the transceiver 603, such as being connected through a communication bus.

[0208] The following specifically introduces each component of the communication device 600 with reference to FIG. 6:

[0209] The processor 601 is the control center of the communication device 600 and can be a single processor or a collective term for multiple processing elements. For example, the processor 601 can be one or more central processing units (CPUs), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present application, such as one or more digital signal processors (DSPs) or one or more field programmable gate arrays (FPGAs).

[0210] Optionally, the processor 601 may execute various functions of the communication device 600 by running or executing a software program stored in the memory 602 and calling data stored in the memory 602 .

[0211] In a specific implementation, as an embodiment, the processor 601 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG. 6 .

[0212] In a specific implementation, as an embodiment, the communication device 600 may also include multiple processors, such as the processor 601 and the processor 604 shown in FIG6 . Each of these processors may be a single-core processor (single-CPU) or a multi-core processor (multi-CPU). The processor herein may refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0213] The memory 602 is used to store the software program for executing the solution of the present application, and the execution is controlled by the processor 601. The specific implementation method can refer to the above method embodiment and will not be repeated here.

[0214] Alternatively, the memory 602 may be a read-only memory (ROM) or other type of static storage device that can store static information and instructions, a random access memory (RAM) or other type of dynamic storage device that can store information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 602 may be integrated with the processor 601 or exist independently and be coupled to the processor 601 via an interface circuit (not shown in FIG6 ) of the communication device 600. This embodiment of the present application does not specifically limit this.

[0215] Transceiver 603 is used for communication with other communication devices. For example, communication device 600 may be a terminal, and transceiver 603 may be used to communicate with an access network device or another terminal. For another example, communication device 600 may be an access network device, and transceiver 603 may be used to communicate with a terminal or another access network device.

[0216] Optionally, the transceiver 603 may include a receiver and a transmitter (not shown separately in FIG6 ), wherein the receiver is used to implement a receiving function, and the transmitter is used to implement a sending function.

[0217] Optionally, the transceiver 603 may be integrated with the processor 601 or exist independently and be coupled to the processor 601 through an interface circuit (not shown in FIG. 6 ) of the communication device 600 . This embodiment of the present application does not specifically limit this.

[0218] It should be noted that the structure of the communication device 600 shown in FIG6 does not constitute a limitation on the communication device. An actual communication device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0219] In addition, the technical effects of the communication device 600 can refer to the technical effects of the communication method described in the above method embodiment, and will not be repeated here.

[0220] An embodiment of the present application provides a communication system, which includes a terminal and an access network device.

[0221] Optionally, the communication system may further include: core network equipment.

[0222] It should be understood that the processor in the embodiments of the present application may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0223] It should also be understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0224] The above embodiments can be implemented in whole or in part by software, hardware (such as circuits), firmware or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center via a wired (such as infrared, wireless, microwave, etc.) method. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a tape), an optical medium (for example, a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0225] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0226] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0227] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0228] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0229] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0230] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0231] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0232] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0233] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0234] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A random access method, characterized in that: include: The terminal receives configuration information from the access network device, the configuration information including: multiple uplink carriers, and a correspondence between random access resources of each uplink carrier and multiple downlink carriers; The terminal sends a preamble to the access network device on a random access resource of a first uplink carrier, where the first uplink carrier is one of the multiple uplink carriers; Selecting, by the terminal, a downlink carrier from the multiple downlink carriers according to the random access resource of the first uplink carrier and the corresponding relationship; The terminal monitors the random access response RAR and / or RAR message 4 from the access network device on the selected downlink carrier.

2. The random access method according to claim 1, wherein: The random access resources include one or more of the following: multiple preamble codes, multiple orthogonal cover codes (OCCs), or multiple transmission opportunities, and the corresponding relationship includes one or more of the following: Different preamble codes correspond to different downlink carriers; or, Different orthogonal cover codes OCC correspond to different downlink carriers; or, Different transmission timings correspond to different downlink carriers.

3. The random access method according to claim 2, wherein: The configuration information also includes a first resource configuration mode; The first resource configuration manner is used to evenly distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier among the multiple downlink carriers.

4. The random access method according to claim 3, wherein: The downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or sending timings satisfy: Downlink carrier index = (preamble code index or orthogonal cover code OCC index or sending timing index) mod (total number of downlink carriers corresponding to the random access resources of the first uplink carrier), where mod is a modulo operation.

5. The random access method according to claim 2, wherein: The multiple downlink carriers include a first downlink carrier and at least one second downlink carrier, and the configuration information further includes a second resource configuration mode; The second resource configuration method is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier on the first downlink carrier according to a first weight, and distribute it among the at least one second downlink carrier according to a second weight.

6. The random access method according to claim 5, wherein: The first weight is greater than the second weight.

7. The random access method according to claim 5, wherein: The first weight is smaller than the second weight.

8. The random access method according to any one of claims 5 to 7, characterized in that: The downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or sending timings satisfy: Downlink carrier index = (preamble code index or orthogonal cover code OCC index or sending timing index) mod (weight of the first downlink carrier + sum of the weights of the at least one second downlink carrier), where mod is a modulo operation.

9. The random access method according to claim 2, wherein: The configuration information also includes a third resource configuration mode; The third resource configuration mode is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier among the multiple downlink carriers according to their respective weights.

10. The random access method according to claim 9, wherein: The nth downlink carrier corresponding to different preamble codes or orthogonal cover codes OCC or transmission timings is the downlink carrier that meets the following conditions and has the smallest downlink carrier index: (preamble code index or orthogonal cover code OCC index or transmission timing index) mod W <W(0)+ W(1)+…W(n); W=W(0)+W(1)+…W(n)+…+W(Nn-1); Wherein, W is the sum of the weights of the multiple downlink carriers, W(n) is the weight of the n-th downlink carrier, 0≤n≤Nn-1, and Nn is the number of the multiple downlink carriers.

11. A random access method, characterized in that: include: The access network device sends configuration information, where the configuration information includes: multiple uplink carriers, and a correspondence between random access resources of each uplink carrier and multiple downlink carriers; The access network device receives a preamble from a terminal on a first uplink carrier, where the first uplink carrier is one of the multiple uplink carriers; The access network device selects a downlink carrier from the multiple downlink carriers according to the random access resource of the first uplink carrier and the corresponding relationship; The access network device sends a random access response RAR and / or RAR message 4 to the terminal on the selected downlink carrier.

12. The random access method according to claim 11, wherein: The random access resources include one or more of the following: multiple preamble codes, multiple orthogonal cover codes (OCCs), or multiple transmission opportunities, and the corresponding relationship includes one or more of the following: Different preamble codes correspond to different downlink carriers; or, Different orthogonal cover codes OCC correspond to different downlink carriers; or, Different transmission timings correspond to different downlink carriers.

13. The random access method according to claim 12, wherein: The configuration information also includes a first resource configuration mode; The first resource configuration manner is used to evenly distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier among the multiple downlink carriers.

14. The random access method according to claim 13, wherein: The downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or sending timings satisfy: Downlink carrier index = (preamble code index or orthogonal cover code OCC index or sending timing index) mod (total number of downlink carriers corresponding to the random access resources of the first uplink carrier), where mod is a modulo operation.

15. The random access method according to claim 12, wherein: The multiple downlink carriers include a first downlink carrier and at least one second downlink carrier, and the configuration information further includes a second resource configuration mode; The second resource configuration method is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resources of the first uplink carrier on the first downlink carrier according to a first weight, and distribute them among the at least one second downlink carrier according to a second weight, and the first weight is greater than the second weight.

16. The random access method according to claim 15, wherein: The first weight is greater than the second weight.

17. The random access method according to claim 15, wherein: The first weight is smaller than the second weight.

18. The random access method according to any one of claims 15 to 17, characterized in that: The downlink carriers corresponding to different preamble codes or orthogonal cover codes OCC or sending timings satisfy: Downlink carrier index = (preamble code index or orthogonal cover code OCC index or sending timing index) mod (weight of the first downlink carrier + sum of the weights of the at least one second downlink carrier), where mod is a modulo operation.

19. The random access method according to claim 12, wherein: The configuration information also includes a third resource configuration mode; The third resource configuration mode is used to distribute the random access response RAR and / or RAR message 4 corresponding to the random access resource of the first uplink carrier among the multiple downlink carriers according to their respective weights.

20. The random access method according to claim 17, wherein: The nth downlink carrier corresponding to different preamble codes or orthogonal cover codes OCC is the downlink carrier that satisfies the following conditions and has the smallest downlink carrier index: (preamble code index or orthogonal cover code OCC index or transmission opportunity index) mod W <W(0)+ W(1)+…W(n); W=W(0)+W(1)+…W(n)+…+W(Nn-1); Wherein, W is the sum of the weights of the multiple downlink carriers, W(n) is the weight of the n-th downlink carrier, 0≤n≤Nn-1, and Nn is the number of the multiple downlink carriers.

21. A communication device, characterized in that: include: A processor, the processor being coupled to a memory, the memory being used to store a program or instruction, and when the program or instruction is executed by the processor, causing the apparatus to perform the random access method according to any one of claims 1 to 10, or to perform the random access method according to any one of claims 11 to 20.

22. A computer-readable storage medium, characterized in that A computer program or instruction is stored, which, when executed, causes a computer to perform the random access method according to any one of claims 1 to 10, or the random access method according to any one of claims 11 to 20.

23. A computer program product, characterized in that The computer program product includes computer program code, and when the computer program code is executed on a computer, the computer implements the random access method according to any one of claims 1 to 10, or implements the random access method according to any one of claims 11 to 20.

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