Uplink and downlink frame structure and transmission method of a self-organizing communication system

Abstract

This invention discloses an uplink and downlink frame structure and transmission method for a self-organizing communication system, relating to the field of wireless communication technology. The frame structure includes a downlink frame structure and an uplink frame structure, both with the same period length. The downlink frame structure contains multiple consecutive subframes. The initial subframe of the frame period carries a master synchronization signal for slave nodes to complete time and frequency synchronization. Multiple control subframes are configured at preset intervals, and the remaining subframes are data subframes. Control subframes and data subframes are transmitted uniformly through a physical downlink shared channel. The uplink frame structure contains multiple consecutive subframes, all of which are configured as data subframes. The corresponding transmission method includes a downlink transmission process and an uplink transmission process. The master node sends synchronization signals and control information, and the slave nodes send data in designated uplink data subframes according to uplink scheduling instructions. This invention is applicable to self-organizing communication networks, improving system communication efficiency and reliability.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and specifically to an uplink and downlink frame structure and transmission method for a self-organizing communication system. Background Technology

[0002] Mobile Ad Hoc Networks (MANETs) are multi-hop wireless networks that do not require fixed infrastructure and are autonomously formed by mobile terminals. Unlike traditional cellular networks, each node in an MANET functions as both a host and a router, making it suitable for scenarios where fixed infrastructure cannot be deployed, such as disaster relief and field operations. While applying LTE technology to MANETs can significantly improve network performance, directly applying the traditional LTE frame structure presents several limitations.

[0003] In traditional LTE systems, the primary synchronization signal (PSS) is repeatedly transmitted with a period of 5ms or 10ms. Frequent transmission of the synchronization signal results in significant resource waste. Traditional LTE employs a multi-channel design: downlink includes PDSCH, PDCCH, PCFICH, etc., while uplink includes PUSCH, PUCCH, PRACH, etc. This design necessitates the integration of multiple channel processing modules in the terminal, leading to high hardware costs, complex processing logic, and high power consumption. Existing technologies also employ a design that separates the static and dynamic domains, but the two domains use different channel formats, further increasing processing complexity.

[0004] Existing technologies suffer from problems such as high synchronization overhead, high hardware complexity, and rigid uplink control channels. There is an urgent need for a frame structure and transmission method suitable for self-organizing communication systems that can reduce synchronization overhead, simplify hardware complexity, reduce power consumption, and ensure communication reliability. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide an uplink and downlink frame structure and transmission method for a self-organizing communication system, so as to solve the problems of high overhead of synchronization signal resources, high hardware complexity caused by separation of control and data channels, and rigid configuration of uplink control channels in the prior art.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An uplink and downlink frame structure for a self-organizing communication system includes:

[0008] The downlink frame structure has a frame period of length one period, which contains multiple consecutive subframes, each with a fixed duration, wherein:

[0009] The master synchronization signal is carried in the initial subframe of the frame period, which is used by the slave nodes to complete time synchronization and frequency synchronization.

[0010] Multiple control subframes are configured according to a preset interval, and the remaining subframes are data subframes;

[0011] The control subframes and data subframes are transmitted uniformly through the Physical Downlink Shared Channel (PDSCH). The control information carried by the control subframes includes at least one of uplink scheduling instructions, link status information, and power control commands.

[0012] The uplink frame structure has a frame period of the same length as the downlink frame and contains multiple consecutive subframes, all of which are configured as data subframes.

[0013] Optionally, the first period length is 40ms, and the plurality of consecutive subframes are 40 subframes, each subframe having a duration of 1ms.

[0014] Optionally, the preset interval is configured as one control subframe every 10 subframes, and the control subframes are subframes 0, 10, 20, and 30.

[0015] Optionally, the initial subframe is the first subframe (i.e., subframe 0).

[0016] Optionally, the master synchronization signal adopts the Zadoff-Chu sequence. The slave node receives the master synchronization signal during the access phase to complete time and frequency synchronization. If synchronization is lost, the slave node re-receives the master synchronization signal in the initial subframe of the next frame period to complete synchronization recovery. This design ensures link robustness while avoiding resource waste caused by frequent transmission of synchronization signals.

[0017] Optionally, the control information transmitted by the control subframe through the physical downlink shared channel specifically includes:

[0018] Uplink scheduling instructions: Instructions for the uplink data transmission time and resource block allocation of the slave node; more specifically, including: uplink authorization identifier, used to indicate whether the slave node is authorized to transmit data; uplink time domain resources, used to indicate in which uplink subframes the slave node transmits data; uplink frequency domain resources, used to indicate in which resource blocks the slave node uses to transmit data; and transport block size, used to indicate the amount of data transmitted in this transmission.

[0019] Link status information includes channel quality feedback requests and modulation and coding scheme adjustment instructions; more specifically, it includes MCS (Modulation and Coding Scheme) level, which indicates the modulation scheme (QPSK, 16QAM, 64QAM, etc.) and coding rate used by the slave node; HARQ process information, which indicates the relevant parameters of the Hybrid Automatic Repeat Request; and channel quality indication request, which requests the slave node to report channel quality information.

[0020] Power control command: Indicates the transmit power adjustment value from the slave node, for example, in 1dB increments, with an adjustment range of -10dB to +10dB, used to compensate for channel fading and interference variations.

[0021] Optionally, in the uplink frame structure, the slave node transmits data through the physical uplink shared channel in a designated uplink data subframe according to the uplink scheduling instruction in the downlink control subframe.

[0022] The present invention provides an uplink and downlink frame structure for a self-organizing communication system. By limiting the main synchronization signal to be sent in the initial subframe, unifying the transmission of control and data through the physical downlink shared channel, and configuring all uplink subframes as data subframes, the technical effects of significantly reducing synchronization overhead, significantly simplifying hardware complexity, and significantly reducing power consumption are achieved, while ensuring link reliability and transmission flexibility.

[0023] This invention also provides a transmission method for a self-organizing communication system, applicable to a self-organizing communication system comprising one master node and multiple slave nodes, comprising the following steps:

[0024] Downlink transmission process:

[0025] The master node sends the master synchronization signal in the initial subframe of the frame period;

[0026] The master node transmits control information through the physical downlink shared channel in the control subframe;

[0027] The master node transmits data information through the physical downlink shared channel in the data subframe;

[0028] Uplink transmission process:

[0029] After receiving the master synchronization signal from the node and completing synchronization, it listens to the control subframe to obtain the uplink scheduling command.

[0030] The slave node sends data in the specified uplink data subframe according to the uplink scheduling instruction;

[0031] All subframes in the uplink frame structure are configured as data subframes for use by slave nodes according to scheduling.

[0032] Optionally, the frame period is 40ms, comprising 40 consecutive subframes, each subframe lasting 1ms; the control subframes are subframes 0, 10, 20, and 30.

[0033] Optionally, the slave node receives control commands and data after completing the master synchronization signal synchronization.

[0034] Optionally, the master node employs either a round-robin or service-priority-based scheduling algorithm to allocate uplink data subframe resources to different slave nodes within a control subframe. Round-robin scheduling means the master node allocates uplink resources to each slave node sequentially in a fixed order, suitable for scenarios requiring uniform service distribution and high fairness. Service-priority-based scheduling means the master node sets priorities based on service type (emergency control, video transmission, sensor data, etc.), allocating resources to higher-priority services first, suitable for scenarios such as emergency communications.

[0035] This invention also provides a transmission method for a self-organizing communication system. By centrally controlling the transmission of synchronization signals, scheduling of control information, and data transmission through the master node, it achieves the technical effects of rapid access of slave nodes, simplified transmission process, and significantly reduced latency. At the same time, it supports dynamic node access and flexible resource scheduling, and is suitable for various scenarios such as low-power sensing and emergency communication.

[0036] The uplink and downlink frame structure and transmission method of the self-organizing communication system provided by this invention together constitute a complete self-organizing communication solution, forming technical advantages in terms of resource efficiency, hardware cost, power consumption control and transmission performance that meet the specific needs of self-organizing networks.

[0037] The beneficial effects of this invention are as follows:

[0038] 1. Significantly reduced synchronization resource overhead: This invention sends PSS only once in subframe 0 within a 40ms period, occupying only 1 subframe, reducing synchronization resource overhead to 2.5% (1 / 40), a 75% reduction compared to the traditional solution's 10% (4 / 40), resulting in a significant decrease in terminal power consumption.

[0039] 2. Reduced hardware complexity and dual optimization of cost and power consumption: In traditional multi-channel schemes, slave nodes need to integrate at least four core processing modules such as PDSCH, PDCCH, PCFICH, and PUCCH. In this invention, control and data are uniformly transmitted through PDSCH. The reduction in modules can eliminate the need for processing chips and storage units of modules such as PDCCH and PCFICH, reducing the hardware cost of slave nodes by 30%-40%.

[0040] 3. Simplified transmission process and reduced latency: This invention eliminates the need for a complex link establishment process. After the node completes PSS synchronization, it can receive control commands and data. Compared with traditional solutions that require establishing a wireless link first and suffer from long latency due to multi-channel detection, this invention simplifies the transmission process and is suitable for latency-sensitive scenarios such as emergency communication.

[0041] 4. High adaptability: Through optimized frame structure design, it takes into account both the real-time performance of control signaling and the utilization rate of data transmission resources, adapts to the real-time requirements of different services, and meets the core requirements of "low cost and low power consumption" of self-organizing networks. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the network topology of the self-organizing communication system of the present invention;

[0044] Figure 2 This is a schematic diagram of the downlink frame structure of the present invention;

[0045] Figure 3 This is a schematic diagram of the uplink frame structure of the present invention;

[0046] Figure 4 This is a schematic diagram of intra-frame resource allocation according to the present invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and beneficial effects of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] This invention achieves efficient communication between master and slave nodes by optimizing the uplink and downlink frame structure period, synchronization signal distribution, and channel carrying method. The specific solution is as follows:

[0049] The present invention discloses an uplink and downlink frame structure for a self-organizing communication system, comprising a downlink frame structure and an uplink frame structure. The downlink frame structure has a frame period of a first cycle length and contains multiple consecutive subframes. The initial subframe of the frame period (e.g., subframe 0) carries a master synchronization signal for slave nodes to perform time and frequency synchronization. Subframe 0 is the initial subframe and simultaneously carries the master synchronization signal and control information. Specifically, the first OFDM symbol (symbol 0) of subframe 0 is used to transmit the master synchronization signal (PSS), occupying the middle six resource blocks (RBs) of the system bandwidth in the frequency domain. The remaining OFDM symbols (symbols 1 to 13) are used to transmit control information, carried through the Physical Downlink Shared Channel (PDSCH). The control information and the master synchronization signal are time-division multiplexed within the same subframe and do not conflict with each other.

[0050] The downlink frame structure configures multiple control subframes at preset intervals within a frame period, with the remaining subframes being data subframes. Both control and data subframes in the downlink frame structure are transmitted through the physical downlink shared channel. The control information carried by the control subframe includes at least one of uplink scheduling commands, link status information, and power control commands. The uplink frame structure has a frame period of the same length as the downlink frame. The uplink frame structure contains multiple consecutive subframes, all of which are configured as data subframes.

[0051] In a specific embodiment, such as Figures 1-4 As shown, this communication system includes one master node and multiple slave nodes. The master node establishes bidirectional communication connections with each slave node, forming a star or chain topology. The master node is responsible for transmitting synchronization signals, resource scheduling, and distributing control information for the entire system. Its function is similar to a base station in a cellular network, but its implementation is simplified. Slave nodes are responsible for receiving control commands and executing data transmission; they are typically battery-powered mobile terminals or sensor devices. The basic parameters of this system are configured as follows: subcarrier spacing is 15kHz, consistent with the LTE system for hardware compatibility; OFDM uses a normal cyclic prefix configuration; subframe duration is 1ms, containing 14 OFDM symbols; frame period is 40ms, containing 40 consecutive subframes; control subframe interval is 10ms, i.e., one control subframe is configured every 10 subframes; system bandwidth can be selected as 5MHz, 10MHz, or 20MHz, flexibly configured according to service requirements and the number of nodes.

[0052] The uplink and downlink frame structures of this self-organizing communication system include downlink frame structures and uplink frame structures. For example... Figure 2 As shown, the initial subframe of the frame period carries a master synchronization signal for slave nodes to complete time and frequency synchronization. Multiple control subframes are configured at preset intervals, while the remaining subframes are data subframes. Control and data subframes are transmitted uniformly through the physical downlink shared channel. The control information carried by the control subframe includes at least one of uplink scheduling instructions, link status information, and power control commands. The uplink scheduling instruction includes a slave node identification field, which uses an explicit node number or an implicit Radio Network Temporary Identifier (RNTI) to indicate the target slave node corresponding to the current scheduling instruction, ensuring that multiple slave nodes can correctly distinguish their respective scheduling resources. The link status information includes HARQ process information, supporting synchronous non-adaptive HARQ retransmission. After uplink data transmission, the master node feeds back ACK / NACK via the HARQ acknowledgment field in the downlink control subframe. The slave node retransmits the data at the predetermined retransmission time based on the feedback information, without requiring additional scheduling signaling.

[0053] like Figure 3As shown, the uplink frame structure has a frame period of the same length as the downlink frame, containing multiple consecutive subframes. All subframes are configured as data subframes, and slave nodes transmit data through the Physical Uplink Shared Channel (PUSCH). The uplink does not have a separate uplink control subframe; all uplink control information (such as HARQ acknowledgments and channel quality indications) is managed in a closed loop through scheduling instructions in the downlink control subframes, or transmitted in-band through the PUSCH. The uplink scheduling instruction includes a slave node identifier field, indicating the target slave node corresponding to the current scheduling instruction; additionally, it may include an uplink grant identifier (1 bit), indicating whether the slave node is permitted to transmit data on allocated resources, used for fast activation / deactivation control.

[0054] In this embodiment, the first period length is 40ms, and there are 40 consecutive subframes, each with a duration of 1ms. This design ensures that the frame period and the number of subframes are perfectly matched, facilitating system synchronization and resource allocation.

[0055] In this embodiment, a control subframe is configured at a preset interval of one control subframe every 10 subframes. Specifically, within the frame period, subframes 0, 10, 20, and 30 are control subframes, with subframe 0 also serving as the initial subframe carrying the main synchronization signal. This uniformly distributed control subframe configuration maximizes data transmission efficiency while ensuring timely transmission of control information.

[0056] In this embodiment, the initial subframe is the first subframe, i.e., subframe 0. This initial subframe carries the primary synchronization signal (PSS), such as... Figure 2 As shown. Specifically, subframe 0 is a special subframe that carries both synchronization signals and control information. Specifically, the first OFDM symbol of subframe 0 (symbol 0) is used to transmit the master synchronization signal (PSS), which occupies the middle 6 resource blocks (RBs) of the system bandwidth in the frequency domain.

[0057] For example, the primary synchronization signal uses the Zadoff-Chu sequence, the sequence length of which is determined by the system bandwidth. In the frequency domain, it maps to the six resource blocks (72 subcarriers) at the center of the system bandwidth. The sequence root number can be configured as 25, 29, or 34, maintaining compatibility with the LTE system. The slave node performs sliding correlation between the received signal and a locally pre-stored sequence, detecting correlation peaks to achieve time synchronization, and estimates carrier frequency deviation through peak phase rotation. The core function of PSS is to enable slave nodes to perform time synchronization (accurately determining the subframe start time) and frequency synchronization (correcting carrier frequency deviation). Its detection principle involves the slave node performing cross-correlation calculations between the received signal and three locally generated possible PSS sequences, determining the time synchronization point by detecting the correlation peak position, and estimating the frequency deviation through peak phase rotation, thereby achieving fast and accurate synchronization acquisition. The remaining 13 OFDM symbols (symbols 1 to 13) of subframe 0 are used to transmit control information, which is carried through the Physical Downlink Shared Channel (PDSCH). Tail-biting convolutional coding (constrained length 7, coding rate 1 / 3) and QPSK modulation are used to ensure that the control information can still be reliably transmitted under poor channel conditions. When the control information is mapped to the resource elements of the PDSCH, a distributed mapping method is used to obtain frequency diversity gain.

[0058] The primary synchronization signal uses the Zadoff-Chu sequence. During the access phase, slave nodes receive the primary synchronization signal to achieve time and frequency synchronization. If synchronization is lost, the slave node re-receives the primary synchronization signal in the initial subframe of the next frame period to restore synchronization. The Zadoff-Chu sequence has good autocorrelation characteristics, facilitating slave node detection. This sequence enables subframe start-time alignment (time synchronization) and carrier frequency deviation correction (frequency synchronization), ensuring link robustness.

[0059] The control information transmitted through the physical downlink shared channel in the control subframe specifically includes: uplink scheduling instructions, indicating the uplink data transmission time and resource block allocation of the slave nodes; link status information, including channel quality feedback requirements and modulation / coding scheme adjustment instructions; and power control commands, indicating the slave node's transmit power adjustment value. For example... Figure 4 As shown, the control subframe contains a dedicated OFDM symbol resource allocation for transmitting this control information.

[0060] Optionally, in addition to subframe 0, subframes 10, 20, and 30 are also configured as control subframes. These pure control subframes do not carry PSS, and all 14 OFDM symbols are used for PDSCH transmission of control information. The coding and modulation method is the same as that of the control information part of the initial subframe. The uplink scheduling command includes an uplink authorization identifier (1 bit, indicating whether the slave node is authorized to send data), an uplink time domain resource indicator (6 bits, indicating the starting subframe and the number of consecutive subframes), an uplink frequency domain resource indicator (8 bits, indicating the starting RB and the number of consecutive RBs), and a transport block size index (5 bits, the specific number of bytes is obtained by looking up a table); the link state information includes an MCS level indicator (5 bits, supporting QPSK, 16QAM, 64QAM and multiple coding rates), a HARQ process number (3 bits, supporting 8 parallel HARQ processes), a new data indicator NDI (1 bit), and a redundancy version RV (2 bits); the power control command is the TPC command (2 bits, indicating power adjustment of -1dB, 0dB, +1dB or +3dB).

[0061] In addition to the four special subframes mentioned above, the remaining 35 subframes are data subframes that transmit service data via PDSCH. The encoding method is Turbo encoding or LDPC encoding, with an adaptive encoding rate (selectable from 1 / 3, 1 / 2, 2 / 3, 3 / 4, etc.). The modulation method is adaptively selected according to the channel conditions, choosing QPSK, 16QAM, or 64QAM. Resource allocation supports centralized allocation (continuous RB, suitable for low-speed mobile scenarios) and distributed allocation (interval RB, suitable for high-speed mobile scenarios).

[0062] In the uplink frame structure, such as Figure 3 As shown, the slave node transmits data through the physical uplink shared channel in the designated uplink data subframe according to the uplink scheduling instructions in the downlink control subframe. The uplink frame period is the same as the downlink frame (40ms), containing 40 consecutive subframes (subframe 0 to subframe 39). All subframes are data subframes, eliminating the need for a dedicated uplink control subframe, thus simplifying the uplink transmission structure and improving data transmission efficiency.

[0063] Specifically, taking a 40ms frame period as an example, the uplink frame structure contains 40 consecutive subframes (subframe 0 to subframe 39), all of which are configured as data subframes, without dedicated uplink control subframes. The technical principle behind this design is the adoption of a downlink centralized control information strategy. All control information (including uplink scheduling commands) is transmitted by the master node via PDSCH in the downlink control subframes. The slave node only needs to passively receive and execute the data, without needing to provide uplink feedback control information. Uplink data transmission is purely performed, thus significantly simplifying the transmitter design of the slave node. In traditional LTE systems, the slave node transmitter needs to support PUSCH (carrying data and some control information such as ACK / NACK multiplexing), multiple formats of PUCCH (formats 1 / 1a / 1b / 2 / 2a / 2b for different control information), and PRACH (random access preamble). However, the slave node transmitter of this invention only needs to support pure PUSCH data transmission. The control information is entirely indicated by the downlink PDSCH. The transmitter processing flow is simplified to encoding, modulation, DFT precoding, subcarrier mapping, IFFT, CP addition, and upconversion. It eliminates the complex functions of dedicated modulation and coding of PUCCH and PRACH preamble sequence generation, which significantly reduces hardware complexity and power consumption.

[0064] Figure 4 This paper demonstrates OFDM symbol resource allocation in different types of subframes, including PSS and PDCCH configurations for the initial subframe, PDCCH configurations for control subframes, and data transmission configurations for downlink and uplink data subframes. This resource allocation method enables efficient transmission of control and data information, meeting the needs of self-organizing communication systems. Through this design, the system can maintain efficient operation in complex communication environments, ensuring reliable transmission of data and control information.

[0065] For example, in a specific embodiment, a typical low-power sensor network application scenario is shown. The system is configured with a bandwidth of 5MHz, a subcarrier spacing of 15kHz, 512 FFT points, 25 resource blocks (25 RBs in the center and guard bands on both sides), a frame period of 40ms, and 4 slave nodes (UE1, UE2, UE3, UE4). The downlink transmission timing is arranged as follows: Symbol 0 of subframe 0 transmits the PSS (6 RBs in the middle, 72 subcarriers); symbols 1-13 transmit control information (PDSCH, full bandwidth of 25 RBs). The control information contains scheduling instructions for 4 slave nodes, specifically: UE1 grants subframes 11-15, RB0-6, MCS=QPSK 1 / 3, TBS=256 bytes; UE2 grants subframes 16-20, RB0-6, MCS=QPSK 1 / 3, TBS=256 bytes; UE3 grants subframes 21-25, RB0-6, MCS=QPSK 1 / 3, TBS=256 bytes; UE4 grants subframes 26-30, RB0-6, MCS=QPSK. 1 / 3, TBS = 256 bytes; subframes 1-9 are for PDSCH data transmission (broadcast or unicast service data); subframe 10 is a control subframe, updating scheduling information, power control adjustment, and HARQ feedback; subframes 11-39 continue PDSCH data transmission. The uplink transmission timing is as follows: UE1 sends data via PUSCH (RB0-6, QPSK 1 / 3) in subframes 11-15, UE2 sends data in subframes 16-20, UE3 sends data in subframes 21-25, and UE4 sends data in subframes 26-30. Under this configuration, the synchronization overhead is 1 subframe / 40ms, or 2.5% (compared to 10% in traditional LTE solutions), the control overhead is 4 subframes / 40ms, or 10%, and the data transmission efficiency is 35 subframes / 40ms, or 87.5%. Each UE can transmit 1280 bytes (256 bytes × 5 subframes) every 40ms, meeting the sensor data reporting requirements.

[0066] In a specific embodiment, the dynamic scheduling process of a 20MHz bandwidth multi-priority service system is demonstrated. This is an emergency communication scenario. The system is configured with a 20MHz bandwidth, 2048 FFT points, 100 resource blocks, and 8 slave nodes. The service types are divided into three categories: UE1 and UE2 are for emergency control services (highest priority, latency requirement less than 5ms), UE3 and UE4 are for video transmission services (high priority, rate requirement greater than 2Mbps), and UE5 to UE8 are for sensor data services (normal priority, periodic reporting). The control information allocation for subframe 0 is as follows: UE1 and UE2 are authorized to subframes 1-2, RB0-49, MCS=16QAM3 / 4 (high bit rate, low latency); UE3 and UE4 are authorized to subframes 3-12, RB0-49, MCS=QPSK 1 / 2 (robust transmission, high reliability); and UE5 to UE8 are authorized to subframes 13-35, RB50-99, MCS=QPSK 1 / 3 (low bit rate, high coverage). When UE1 detects an emergency event (such as a fire alarm), it sends an emergency data indication in the allocated subframes 1-2. Upon receiving the indication in the control subframe of subframe 10, the master node immediately adjusts the scheduling, suspending transmissions from UE5 to UE8 and reallocating RB50-99 to UE1. UE1 then obtains additional resources in subframes 11-15 to send detailed alarm information. Normal scheduling resumes in the control subframe of subframe 20. This priority-based dynamic scheduling mechanism ensures low-latency transmission of emergency services while maintaining fairness for ordinary services.

[0067] The present invention provides an uplink and downlink frame structure for a self-organizing communication system. By limiting the main synchronization signal to be sent in the initial subframe, unifying the transmission of control and data through the physical downlink shared channel, and configuring all uplink subframes as data subframes, the technical effects of significantly reducing synchronization overhead, significantly simplifying hardware complexity, and significantly reducing power consumption are achieved, while ensuring link reliability and transmission flexibility.

[0068] according to Figure 1 The diagram shows a self-organizing communication system network topology, consisting of a master node and multiple slave nodes. Information is transmitted between the master node and each slave node through bidirectional communication connections. Next, a transmission method specifically applied to this system will be described in detail.

[0069] In this transmission method, the communication process between the master node and the slave node is divided into two parts: downlink transmission and uplink transmission, to ensure the effective transmission of information.

[0070] The downlink transmission process includes the following steps:

[0071] Step 1: The master node sends the master synchronization signal in the initial subframe of the frame period.

[0072] Specifically, such as Figure 2 As shown, the master node transmits the primary synchronization signal (PSS) in the first subframe (i.e., subframe 0) of a 40ms frame period. This PSS uses a ZC sequence, which is easily detected by slave nodes due to its good autocorrelation characteristics. Slave nodes receive the PSS signal during the access phase, completing time synchronization (i.e., subframe start time alignment) and frequency synchronization (i.e., carrier frequency deviation correction). If synchronization is lost, the slave node can re-receive the PSS in subframe 0 of the next frame period to restore synchronization, thus ensuring the robustness and stability of the link.

[0073] Step 2: The master node sends control information through the physical downlink shared channel in the control subframe.

[0074] like Figure 2 As shown, within a 40ms frame period, subframes 0, 10, 20, and 30 are configured as control subframes, with a duration of 1ms. The master node transmits control information through the Physical Downlink Shared Channel (PDSCH). This information includes uplink scheduling commands (such as the uplink data transmission time of slave nodes and resource block allocation), link status information (such as channel quality feedback requirements and modulation / coding scheme adjustments), and power control commands (such as slave node transmit power adjustment values).

[0075] Step 3: The master node transmits data information through the physical downlink shared channel in the data subframe.

[0076] like Figure 2 As shown, apart from the four control subframes, the remaining subframes (i.e., subframes 1-9, 11-19, 21-29, and 31-39) are all data subframes. The master node transmits service data in these data subframes through the Physical Downlink Shared Channel (PDSCH). Figure 4 It further illustrates the resource allocation within the subframe, including the data transmission configuration of the downlink data subframe.

[0077] The uplink transmission process includes the following steps:

[0078] Step 1: After receiving the master synchronization signal from the node and completing synchronization, listen to the control subframe to obtain uplink scheduling instructions.

[0079] After receiving the Master Synchronization Signal (PSS) in subframe 0 and completing synchronization, the slave node begins listening to control subframes 0, 10, 20, 30, etc., to obtain the uplink scheduling instructions sent by the master node. These instructions contain detailed information about when and where the slave node should send uplink data.

[0080] Step 2: The slave node sends data in the specified uplink data subframe according to the uplink scheduling instruction.

[0081] Slave nodes transmit data in designated uplink data subframes according to the resources and time allocated by the master node in the control subframe. The master node uses a round-robin or service priority-based scheduling algorithm to allocate uplink data subframe resources to different slave nodes in the control subframe. This ensures that multiple slave nodes can transmit data to the master node in an orderly manner, avoiding conflicts.

[0082] Step 3: The slave node transmits data in the designated uplink data subframe according to the uplink scheduling instructions in the downlink control subframe. All subframes in the uplink frame structure are configured as data subframes for use by the slave node according to the schedule.

[0083] like Figure 3 As shown, the uplink frame period is the same as the downlink frame period (40ms), and it contains 40 consecutive subframes (subframe 0 to subframe 39). Figure 4 The data transmission configuration of the uplink data subframe is shown.

[0084] In this transmission method, the frame period is 40ms, consisting of 40 consecutive subframes, each with a duration of 1ms. Control subframes are designated as subframes 0, 10, 20, and 30, with one control subframe configured every 10 subframes, for a total of four. This design ensures that control information is transmitted periodically, guaranteeing stable system operation.

[0085] After completing synchronization with the master synchronization signal, the slave node receives control commands and data. Specifically, the slave node first receives the PSS signal in subframe 0 to complete synchronization, then listens to the control subframe to obtain control commands based on the synchronization information, and finally receives data in the data subframe or sends data in the uplink subframe according to the control commands.

[0086] The master node uses either a round-robin or service-priority-based scheduling algorithm to allocate uplink data subframe resources to different slave nodes within the control subframe. The round-robin algorithm allocates resources to each slave node sequentially according to a predetermined order, ensuring fairness; while the service-priority-based scheduling algorithm allocates resources to slave nodes based on the urgency and importance of the service type, ensuring that high-priority services can be transmitted in a timely manner.

[0087] Through this frame structure and transmission method design, the self-organizing communication system can achieve efficient communication between master and slave nodes, ensuring the system's synchronization, reliability, and flexibility.

[0088] The embodiments described above are merely illustrative of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the present invention.

Claims

1. An uplink and downlink frame structure for a self-organizing communication system, characterized in that, include: The downlink frame structure has a frame period of a first period length, wherein the frame period contains multiple consecutive subframes, each subframe having a fixed duration, wherein: The master synchronization signal is carried in the initial subframe of the frame period, which is used by the slave nodes to complete time synchronization and frequency synchronization. Multiple control subframes are configured according to a preset interval, and the remaining subframes are data subframes; The control subframes and data subframes are transmitted uniformly through the physical downlink shared channel. The control information carried by the control subframes includes at least one of uplink scheduling instructions, link status information, and power control commands. The uplink frame structure has a frame period of the same length as the downlink frame and contains multiple consecutive subframes, all of which are configured as data subframes.

2. The uplink / downlink frame structure according to claim 1, characterized in that, The first period length is 40ms, and the multiple consecutive subframes are 40 subframes, each subframe having a duration of 1ms.

3. The uplink / downlink frame structure according to claim 2, characterized in that, The preset interval is one control subframe configured every 10 subframes, and the control subframes are subframes 0, 10, 20, and 30.

4. The uplink / downlink frame structure according to claim 1, characterized in that, The initial subframe is the first subframe.

5. The uplink / downlink frame structure according to any one of claims 1-4, characterized in that, The master synchronization signal adopts the Zadoff-Chu sequence. The slave node receives the master synchronization signal during the access phase to complete time synchronization and frequency synchronization. If synchronization is lost, the slave node will receive the master synchronization signal again in the initial subframe of the next frame period to complete synchronization recovery.

6. The uplink / downlink frame structure according to any one of claims 1-4, characterized in that, The control information transmitted by the control subframe through the physical downlink shared channel specifically includes: Uplink scheduling command: Indicates the uplink data transmission time and resource block allocation of the slave node; Link status information includes channel quality feedback requirements and modulation / coding scheme adjustment instructions; Power control command: Indicates the transmit power adjustment value from the slave node.

7. The uplink / downlink frame structure according to any one of claims 1-4, characterized in that, In the uplink frame structure, the slave node transmits data through the physical uplink shared channel in the designated uplink data subframe according to the uplink scheduling instruction in the downlink control subframe.

8. A transmission method for a self-organizing communication system, applied to a self-organizing communication system comprising one master node and multiple slave nodes, characterized in that, Includes the following steps: Downlink transmission process: The master node sends the master synchronization signal in the initial subframe of the frame period; The master node transmits control information through the physical downlink shared channel in the control subframe; The master node transmits data information through the physical downlink shared channel in the data subframe; Uplink transmission process: After receiving the master synchronization signal from the node and completing synchronization, it listens to the control subframe to obtain the uplink scheduling command. The slave node sends data in the specified uplink data subframe according to the uplink scheduling instruction; All subframes in the uplink frame structure are configured as data subframes for use by slave nodes according to scheduling.

9. The transmission method according to claim 8, characterized in that, The frame period is 40ms, which includes 40 consecutive subframes, each with a duration of 1ms; the control subframes are subframes 0, 10, 20, and 30.

10. The transmission method according to claim 8, characterized in that, After the slave node completes the master synchronization signal synchronization, it receives control commands and data.

11. The transmission method according to claim 8, characterized in that, The master node uses a polling or service priority-based scheduling algorithm to allocate uplink data subframe resources to different slave nodes in the control subframe.

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