CN111818653B - Resource allocation method of wireless ad hoc network - Google Patents

Abstract

The invention discloses a resource allocation method of a wireless ad hoc network, in which a communication node transmits SIB messages and service data packets in a first type transmission time slot within a SIB message period, and transmits service data in a second type transmission time slot packet; each SIB message is mapped to static time-frequency resources in one or more first-type transmission time slots, and the physical layer control information and service data packets of each service data packet transmission are mapped to one first-type transmission time slot On different physical channels on the dynamic time-frequency resources within; For the same communication node, if the SIB message is transmitted on the static time-frequency resources within the first type transmission time slot #n, it can only transmit SIB messages in the transmission time slot #n Data packet transmission is performed on the dynamic time-frequency resources in +k and subsequent transmission time slots, and the SIB message does not change at the moment of data packet transmission; the present invention reduces the average transmission of the wireless broadband ad hoc network by optimizing the allocation of time-frequency resources Delay, improve the transmission efficiency of the network.

Description

A resource allocation method for wireless ad hoc network

technical field

The invention relates to the technical field of ad hoc networks, in particular to a resource allocation method for a wireless ad hoc network.

Background technique

Wireless ad hoc network is a new type of wireless network architecture completely different from traditional wireless cellular networks, including a temporary autonomous network of multiple communication nodes. The nodes in the network are all equal, and each communication node is equipped with a wireless transceiver, which has the functions of sending, forwarding and receiving, so any two nodes in the network can communicate through a direct link or a multi-hop link. Compared with traditional cellular networks, wireless ad hoc networks do not need to rely on infrastructure, and have the advantages of flexible and simple networking, high network reliability, and large coverage. They are widely used in public security, military battlefields, post-disaster reconstruction, and first aid missions.

With the rapid development of multimedia service requirements and the mature application of broadband communication technology represented by OFDM-MIMO (Orthogonal Frequency Division Multiple Access and Multiple Input Multiple Output) technology, the wireless ad hoc network based on broadband communication technology emerges as needed . Due to the lack of unified technical specifications for wireless broadband ad hoc networks, some manufacturers usually use existing wireless broadband communication technologies to develop customized wireless ad hoc network nodes based on private protocols by modifying or referring to existing wireless broadband cellular network communication protocols , such as WiFi protocol and 4G LTE protocol.

In the wireless broadband ad hoc network, each communication node needs to periodically broadcast SIB (System Information Block, system information block) information, which is used to notify other nodes of system information related to configuration. Since the SIB message is periodically and fixedly transmitted, the prior art usually allocates static time-frequency resources for it, that is, each communication node allocates a fixed time-frequency resource for transmitting the SIB message in each sending period. For service data packets, each communication node can only transmit on the dynamically allocated time-frequency resources when there is a sending opportunity. Compared with the purely static resource allocation method, this allocation method increases the flexibility of the network to a certain extent.

In a commonly used TDMA (Time Division Multiplexing Access, Time Division Multiple Access) resource multiplexing method, each communication node usually allocates a time-frequency resource of a transmission time slot in a SIB message cycle for SIB message transmission, that is, a All frequency domain resources on the working frequency band within the transmission slot. For all communication nodes, a plurality of continuous transmission time slots (equal to the number of communication nodes) are allocated in one SIB message cycle for SIB message transmission, and the remaining transmission time slots in one cycle are dynamic time-frequency resources for data packet transmission ,As shown in Figure 1. Since each communication node corresponds to a static transmission time slot, in order to simplify the system design, usually only one communication node is allowed to send data packets in the dynamic transmission time slot. For the wireless ad hoc network with small network scale and few communication nodes, the proportion of resources occupied by the static transmission time slot is small, and the impact on the throughput of the network is small. However, for wireless ad hoc networks with a large network scale and a large number of communication nodes, static transmission time slots occupy a large proportion of resources. In extreme cases, all time-frequency resources will be allocated to SIB messages, resulting in very low network throughput. For example, in a wireless ad hoc network including 32 communication nodes, assuming that the SIB message period is 60 transmission time slots, only 24 transmission time slots are available for dynamic resources for data transmission. When the number of communication nodes increases further, the dynamic resources used for data transmission decrease accordingly.

In the prior art, a transmission slot is usually a basic unit of time-domain resource division, and each transmission slot includes multiple minimum time-domain resource units. For example, in a wireless broadband ad hoc network based on LTE (Long Term Evolution, Long Term Evolution) technology, the basic unit of time domain resources is a subframe (namely 1 ms), and the minimum time domain resource unit is OFDM (Orthogonal Frequency Division Multiplexing, Orthogonal Frequency Division Multiplexing, Division Multiple Access) symbols, one subframe contains 14 OFDM symbols. In the transmission time slot used for data packet transmission, all time-frequency resources are divided into different transmission channels according to technical specifications, used to carry different types of data packet transmission, mainly including physical control channels, physical shared channels, etc., as shown in Figure 2 shown.

Contents of the invention

In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a resource allocation method for wireless ad hoc networks, by dividing different types of transmission time slots, optimizing the time-frequency resource allocation methods of wireless ad hoc networks, and reducing the resources occupied by SIB messages The influence of the proportion and the number of communication nodes on the network throughput reduces the average transmission delay of the wireless broadband ad hoc network, improves the network throughput, and improves the transmission efficiency of the network.

In order to solve the problems of the technologies described above, the present invention adopts the following technical solutions:

The present invention provides a resource allocation method for a wireless ad hoc network, including:

The communication node transmits the SIB message and the service data packet in the first type of transmission time slot in one SIB message period, and transmits the service data packet in the second type of transmission time slot;

The first type of transmission slot is divided into static time-frequency resources and dynamic time-frequency resources according to the minimum time-domain resource unit; each SIB message is mapped to static time-frequency in one or more first-type transmission slots In terms of resources, the physical layer control information and service data packets of each service data packet transmission are mapped to different physical channels on a dynamic time-frequency resource within a first-type transmission time slot;

For the same communication node, if the SIB message is transmitted on the static time-frequency resource in the first type transmission time slot #n, it can only transmit the dynamic time-frequency resource in the transmission time slot #n+k and the subsequent time slot The data packet is transmitted on the resource, and the SIB message does not change at the moment of data packet transmission, where k>0.

Preferably, a SIB message cycle is the time interval between two consecutive SIB message transmissions, and the time interval is composed of T consecutive transmission time slots;

Wherein, the T consecutive transmission slots include T1 consecutively distributed first-type transmission slots and T2 consecutively distributed second-type transmission slots, and T1+T2=T, T1>0, T2≥0.

Preferably, in the first type of transmission time slot, static time-frequency resources are used to carry SIB messages, and another part of dynamic time-frequency resources are used to carry service data packets and physical layer control information related to service data packet transmission;

In the second type of transmission time slot, all dynamic time-frequency resources are used to carry service data packets and physical layer control information related to the transmission of service data packets.

Preferably, in the first type of transmission slot, one transmission slot includes X minimum time domain resource units, the first X1 minimum time domain resource units are static time-frequency resources, and the last X-X1 minimum time domain resource units are Dynamic time-frequency resources, where 0<X1≤X/2.

Preferably, the size of the static time-frequency resource in the first type of transmission time slot is determined by the SIB message period, the number of communication nodes, and the size of the encoded SIB message packet;

In the case of determining X1, if the static time domain resources in a first-type transmission time slot can carry an encoded SIB message data packet, each SIB message data packet is allocated a first-type transmission time slot; otherwise , each SIB message data packet is allocated a plurality of first-type transmission time slots; wherein, M*N=T1≤T, wherein M is the number of first-type transmission time slots allocated to each SIB message data packet, and N is a communication node number.

The beneficial effects of the present invention are:

(1) The combination of different types of transmission time slots and the combination of static resources and dynamic resource allocation increase the flexibility of network transmission;

(2) On the basis of satisfying the SIB message transmission, the time-frequency resource occupation ratio of the SIB message is reduced, and the throughput of the network is effectively improved.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

FIG. 1 is a resource allocation method in the prior art;

Fig. 2 is the physical channel division in the subframe of the wireless broadband ad hoc network based on LTE technology in the prior art;

Fig. 3 is the division of different types of transmission time slots in a SIB cycle of the present invention;

Fig. 4 is the division of static time-frequency resources and dynamic time-frequency resources in the first type of transmission time slot of the present invention;

Fig. 5 is the physical channel division in the first type transmission time slot of the present invention;

FIG. 6 is the sequence of SIB message transmission and data packet transmission of the same node in the present invention.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The present invention provides a resource allocation method of a wireless ad hoc network, specifically as follows:

1. The communication node transmits in the continuous transmission time slots of one SIB message period, wherein the set of continuous transmission time slots of one SIB message period includes the first type transmission time slot and the second type transmission time slot, and the communication node transmits in the first SIB messages and service data packets are transmitted in the first-type transmission time slots, and only service data packets are transmitted in the second-type transmission time slots;

Among them, a SIB message period refers to the time interval between two consecutive SIB message transmissions, which is composed of T consecutive transmission time slots; as shown in Figure 3, T consecutive transmission time slots include T1 consecutive The distributed first-type transmission slots and T2 consecutively distributed second-type transmission slots, and T1+T2=T, T1>0, T2≥0; from the perspective of time domain, the first type of transmission slots are located at Before the second type transmission slot.

In the first type of transmission time slot, the transmission time slot is divided into two parts according to the minimum time-domain resource unit, one part is static time-frequency resources for carrying SIB messages, and the other part is dynamic time-frequency resources for carrying service data packet and the physical layer control information related to the transmission of business data packets. Suppose a transmission slot includes X minimum time-domain resource units, the first X1 minimum time-domain resource units are static time-frequency resources, and the last X-X1 minimum time-domain resource units are dynamic time-frequency resources, where 0<X1≤X /2, as shown in Figure 4;

In the second type of transmission time slot, all dynamic time-frequency resources are used to carry service data packets and the physical layer control information related to the transmission of service data packets (there are only dynamic time-frequency resources in the second type); this transmission time slot The type is the same as the transmission slot used for dynamic time-frequency resources in the prior art.

2. Each SIB message is mapped to one or more static time-frequency resources in the first type of transmission time slot. The size of the static time-frequency resource in the first type of transmission time slot is determined by the SIB message period, the number of communication nodes, and the encoded Determined by factors such as the size of the SIB message packet;

Within a SIB message period T (the value of T must not be less than the number of communication nodes), all static time-frequency resources need to be able to carry the SIB messages corresponding to all communication nodes. Due to the limitation of the SIB message period T, the first type sub The maximum value of the number of frames T1 is T;

(1) The larger the value of the SIB message cycle T is, the larger the value of the first type subframe number T1 can be. When the number of communication nodes and the size of the SIB message packet are fixed, the larger the value of X1 can be in a transmission time slot. Small enough to provide enough static time-frequency resources to carry all SIB messages;

(2) The more the number of communication nodes is, the more SIB messages need to be transmitted. Under the condition that the SIB message period and the SIB message packet size are fixed, if T1<T, then X1 or T1 will be larger; if T1=T, then The bigger X1 is;

(3) The larger the size of the SIB message packet, the more bits of the SIB message to be transmitted, and the larger the static time-frequency resources required; in the case of a fixed SIB message cycle and a fixed number of communication nodes, if T1<T, then X1 Or T1 is bigger; if T1=T, then X1 is bigger;

In general, the value of X1 needs to be determined by considering multiple factors such as the network scale, SIB message configuration period, the number of first-type transmission time slots, and the size of SIB message packets, so as to ensure that the provided static time-frequency resources can satisfy all SIB messages. Transmission requirements; however, when all static time-frequency resources within a SIB cycle can meet all SIB message transmission requirements, X1 is given priority over T1 to provide sufficient static time-frequency resources;

In the case of determining X1, if the static time domain resources in a first-type transmission time slot can carry an encoded SIB message data packet, each SIB message data packet is allocated a first-type transmission time slot; otherwise , each SIB message data packet is allocated a plurality of first-type transmission time slots; wherein, M*N=T1≤T, wherein M is the number of first-type transmission time slots allocated to each SIB message data packet, and N is a communication node number.

3. In the first type of transmission time slot, the communication node transmits physical layer control information and service data packets on different physical channels on the dynamic time-frequency resource. For different physical channels, the frequency domain resource position remains unchanged, and the time domain resource position Change or decrease of time-domain resources, that is, in the present invention, no change occurs to frequency-domain resources;

In the first type of transmission time slot, the communication node can only transmit data packets on the dynamic time-frequency resources within X-X1 minimum time-domain resource units, and the dynamic time-frequency resources need to be divided into different physical channels according to the technical specifications. Used to carry different types of data, for example, the physical control channel carries control information, and the physical shared channel carries data packets, as shown in Figure 5;

The division of different physical channels needs to be based on the technical specifications of the wireless ad hoc network. For example, for the wireless broadband ad hoc network based on LTE technology, in a normal transmission time slot, the physical control channel is generally mapped on the first 1 to 3 OFDM symbols. , the remaining OFDM symbols are used to map the physical shared channel and other physical channels; however, in the first type of transmission slot, considering that the static time domain resource allocates the first X1 OFDM symbols, the physical control channel is mapped in X1+1～ On the X1+3 OFDM symbols, the remaining X-X1-3~X-X1-1 OFDM symbols are used to map the physical shared channel and other physical channels. For the physical shared channel, the allocated OFDM symbol positions and data are has changed;

In the solution of the present invention, each communication node obtains the value of X1 through a configuration message, and divides physical channels through the configuration message and technical specifications.

4. For the same communication node, if the SIB message is transmitted on the static time-frequency resource in the first type transmission time slot #n, it can only transmit the dynamic time-frequency resource in the transmission time slot #n+k and the subsequent time slot Data packet transmission is performed on time-frequency resources, and the SIB message does not change at the time of data packet transmission, where k>0;

Usually, the SIB message is used to notify some configuration messages, and only after other communication nodes know the configuration message, the current communication node can transmit data packets with other communication nodes; therefore, after the transmission of the SIB message, after at least k transmission time slots, the current Communication nodes can transmit service data packets, where the value of k depends on the time when other communication nodes obtain the SIB message of the current communication node, as shown in Figure 6; at the time of data packet transmission, it is also necessary to ensure that the SIB message does not change at this time. Including two cases, the first case is that the current node has not sent the SIB message again after sending the SIB message, and the second case is that the current node has sent the SIB message again, but the contents of the two SIB messages are the same;

The presence of a time gap between SIB messages and packet transmissions will result in two special cases as follows:

(1) In the first SIB transmission cycle just established in the wireless ad hoc network, the dynamic time-frequency resources of the first k first-type transmission time slots will be idle and cannot carry service data packets;

(2) The service data packet and the resent SIB message are transmitted in the same first-type transmission time slot.

Further, in order to illustrate the solution of the present invention more clearly, it is assumed that the wireless broadband ad hoc network is based on LTE technology, the transmission time slot is a subframe of 1 ms, the minimum time-domain resource unit is an OFDM symbol, and each subframe contains 14 OFDM symbols . In a subframe, it is assumed that the time-frequency resources in the first three OFDM symbols are physical control channel regions, and the time-frequency resources in the remaining OFDM symbols are physical shared channel regions.

Assume that the wireless broadband ad hoc network includes 32 communication nodes, and the SIB message transmission period is 80ms; according to the description of the invention solution, in a SIB message period of 80ms, at least 32 first-type transmission time slots (subframes); In the first type of transmission time slot (subframe), assuming that the first X1 OFDM symbols are static time-frequency resources, X1≤7, then one SIB message cycle contains M*32 first type transmission time slots (subframes) and 80-M*32 second-type transmission slots (subframes), the value of M changes with the value of X1; when X≤7, if a static time-frequency resource in a first-type transmission slot (subframe) Enough to carry the coded SIB message packet of a communication node, then the SIB message of each communication node allocates a static time domain resource in a first type transmission time slot (subframe), so M=1; but when X =7, the static time-frequency resource in a first type transmission time slot (subframe) is not enough to carry the coded SIB message data packet of a communication node, then the SIB message of each communication node is allocated M first type Static time-frequency resources in transmission time slots (subframes), ensuring that all static time-frequency resources allocated are sufficient to carry the SIB message of a communication node, at this time M≥2; when M>2, the first type of transmission time slot ( The number of subframes) exceeds the number of subframes in the SIB message cycle, which is a system configuration error and needs to be reconfigured.

The above content reflects the relationship between the size of the static time-frequency resource and the encoded SIB message packet, that is, the static time-frequency resource in a first-type transmission time slot (subframe) is not enough to carry the encoded SIB message packet , it is necessary to configure X1=7 (maximum value); in addition, the static time-frequency resource size is also related to the SIB message period and the number of communication nodes; when the SIB message period increases, if the number of communication nodes remains unchanged, each communication node can allocate More static time-frequency resources in the first type transmission time slot (subframe), the size of each static time-frequency resource can be reduced to ensure that the total static time-frequency resources are sufficient; when the number of communication nodes increases, due to Due to the limitation of the SIB message cycle, the static time-frequency resources in the first type of transmission time slot (subframe) that can be allocated by each communication node are reduced, and the size of each static time-frequency resource needs to be increased to ensure the total static time-frequency resources enough.

In the first type of transmission time slot (subframe), since the first X1 OFDM symbols are allocated as static time-frequency resources, physical control channels and physical shared channels for data packet transmission cannot be mapped on these OFDM symbols. Dynamic time-frequency resources occupy 14-X1 OFDM symbols, and the time-frequency resources on these OFDM symbols need to be re-divided into physical control channels and physical shared channels. As shown in Figure 5, on the dynamic time-frequency resources, the first three OFDM symbols are divided into physical control channel regions, and the remaining OFDM symbols are divided into physical shared channel regions; compared with the physical channel division in Figure 2, the physical shared channel occupies The location of resources changes, and the number of resources decreases; for the second type of transmission time slot (subframe), its physical channel division is shown in FIG. 2 .

In a wireless broadband ad hoc network, when the network is established, all communication nodes first send SIB messages in the first type of transmission time slot (subframe) to notify configuration related information; for communication node i, it is assumed that it is in the subframe The SIB message is sent in frame #n, and after k subframes, other communication nodes in the network obtain the content of the SIB message sent by it; therefore, communication node i can send the message to other communication nodes in the network from the subframe starting from subframe #n+k Send a service data packet; note that no communication node sends a service data packet in the k subframes from subframe #0 to subframe #k-1.

For communication node i, the subframe that sends the service data packet and the subframe #n can be in the same SIB period, or they can be located in different SIB periods, but the SIB between the subframe #n and the subframe that sends the service data packet The message does not change; note that the subframe for transmitting service data packets can be the first type of transmission slot (subframe), or the second type of transmission slot (subframe); when the first type of transmission When slots (subframes) are used, the communication node i may transmit the SIB message again in the static time-frequency resource part, and send the service data packet in the dynamic time-frequency resource part.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies thereof, the present invention also intends to include these modifications and variations.

Claims (3)

1. A method for resource allocation of a wireless ad hoc network, characterized in that, comprising: The communication node transmits the SIB message and the service data packet in the first type of transmission time slot in one SIB message period, and transmits the service data packet in the second type of transmission time slot; The first type of transmission slot is divided into static time-frequency resources and dynamic time-frequency resources according to the minimum time-domain resource unit; each SIB message is mapped to static time-frequency in one or more first-type transmission slots In terms of resources, the physical layer control information and service data packets of each service data packet transmission are mapped to different physical channels on a dynamic time-frequency resource within a first-type transmission time slot; For the same communication node, if the SIB message is transmitted on the static time-frequency resource in the first type transmission time slot #n, it can only transmit the dynamic time-frequency resource in the transmission time slot #n+k and the subsequent time slot The data packet is transmitted on the resource, and the SIB message does not change at the moment of data packet transmission, where k>0; A SIB message period is the time interval between two consecutive SIB message transmissions, and the time interval consists of T consecutive transmission slots; Wherein, the T consecutive transmission slots include T1 consecutively distributed first-type transmission slots and T2 consecutively distributed second-type transmission slots, and T1+T2=T, T1>0, T2≥0; In the first type of transmission slot, a transmission slot includes X minimum time-domain resource units, the first X1 minimum time-domain resource units are static time-frequency resources, and the last X-X1 minimum time-domain resource units are dynamic time-frequency resources resources, where 0<X1≤X/2. 2. the resource allocation method of a kind of wireless ad hoc network as claimed in claim 1, is characterized in that, In the first type of transmission time slot, static time-frequency resources are used to carry SIB messages, and another part of dynamic time-frequency resources are used to carry service data packets and physical layer control information related to service data packet transmission; In the second type of transmission time slot, all dynamic time-frequency resources are used to carry service data packets and physical layer control information related to the transmission of service data packets. 3. The resource allocation method of a kind of wireless ad hoc network as claimed in claim 1, is characterized in that, the static time-frequency resource size in the first type transmission time slot is made up of SIB message period, communication node number, coded SIB The size of the message packet is determined; In the case of determining X1, if the static time domain resources in a first-type transmission time slot can carry an encoded SIB message data packet, each SIB message data packet is allocated a first-type transmission time slot; otherwise , each SIB message data packet is assigned a plurality of first-type transmission time slots; wherein, M*N=T1≤T, wherein M is the number of first-type transmission time slots allocated to each SIB message data packet, and N is a communication node number.

Images