Method for quickly releasing channel in wireless Internet of things communication system
Technical Field
The invention relates to a method for realizing a wireless communication system, in particular to a method for quickly releasing a channel in a wireless Internet of things communication system.
Background
Mobile cellular communication systems include 2G, 3G, 4G, NB-IoT, 5G, etc., which typically include a base station and terminals, the base station being responsible for sending information to and receiving information from the plurality of terminals; a terminal, that is, a terminal device, which is a device located at the outermost periphery of a network in a computer network, is mainly used for inputting user information, outputting a processing result, and the like, and is responsible for transmitting information to a base station and receiving information from the base station; an application terminal (such as a smart water meter or an electric meter) of the internet of things sends or receives information to a network or a server regularly, and then enters a long-time sleep mode including a power saving mode (power saving mode), a Discontinuous Reception (DRX) mode or an extended discontinuous reception (eDRX) mode, so that the purpose of saving power is achieved. In the application of the internet of things, most terminals use batteries, so the more the terminals save electricity, the longer the batteries need to be replaced and the charging period is, the more trouble-saving the user is, and the lower the cost is.
In the LTE communication system, data is transmitted through a Physical Uplink Shared Channel (PUSCH) or a Physical Downlink Shared Channel (PDSCH). Since a plurality of terminals share a Channel, a base station must send Downlink Control Information (DCI) to a terminal through a Physical Downlink Control Channel (PDCCH) to transmit scheduling Information, and the terminal can receive or transmit data on corresponding time and frequency resources after receiving the scheduling Information. The terminal needs a long time to receive a lot of data or waits for a long time to exit the connection state, and then exits the connection state, so that a large amount of air wireless resources and electric quantity of the terminal are wasted, and particularly for a large amount of terminals in weak field signals.
In the LTE communication system, data is transmitted through a Physical Uplink Shared Channel (PUSCH) or a Physical Downlink Shared Channel (PDSCH), and due to a plurality of emtcs (enhanced Machine Type communication) terminal Shared channels, a base station must transmit scheduling Information (DCI) to a terminal through an MTC Physical Downlink Control Channel (M-PDCCH), and the terminal can receive or transmit data on corresponding time and frequency resources after receiving the scheduling Information. The terminal needs a long time to receive a lot of data or waits for a long time to exit the connection state, and then exits the connection state, so that a large amount of air wireless resources and electric quantity of the terminal are wasted, and particularly for a large amount of terminals in weak field signals.
In an NB-IoT communication system, data is transmitted through a Physical Uplink Shared Channel (N-PUSCH) or a Physical Downlink Shared Channel (N-PDSCH), and since a plurality of terminals share the Channel, a base station must transmit Downlink Control Information (DCI) to the terminals through a Physical Downlink Control Channel (N-PDCCH), and the terminals can receive or transmit data on corresponding time and frequency resources after receiving the scheduling Information.
For a terminal actively initiating data connection, as shown in fig. 2, the working process is as follows, after the terminal establishes connection with a base station, the terminal waits for the base station to send an Uplink scheduling command in Downlink Control Information (DCI) to the terminal through a Physical Downlink Control Channel (PDCCH), the terminal initiates data in a Physical Uplink Shared Channel (PUSCH) after receiving the Uplink scheduling command, if the data is a TCP application, the base station schedules the terminal through the Physical Downlink Control Channel and replies ACK of the TCP layer to the terminal in a resource corresponding to the scheduling, and then the terminal maintains a continuous receiving state until a DRX inactive timer is overtime or receives a new PDCCH; if the DRX inactive timer is overtime, entering the DRX in a connection state; if a new PDCCH is received, receiving a PDSCH corresponding to the PDCCH; if the PDSCH includes a connection release message, the terminal releases the radio channel and exits from the connected state. If the connection release message is not contained, the terminal resets the DRX inactive timer and continues to wait for the timeout of the DRX inactive timer or a new PDCCH. The base station needs to transmit a connection release message on the PDSCH, if TCP data are transmitted, the base station also needs to send a TCP layer ACK, wireless resources are wasted, and the terminal needs to receive the PDSCH and wait for the time-out of a DRX active timer, so that the electric quantity of the terminal is wasted;
for a terminal needing to receive data, as shown in fig. 3, the working process is as follows, after the terminal establishes connection with a base station, the terminal waits for the base station to send a Downlink scheduling command in Downlink Control Information (DCI) to the terminal through a Physical Downlink Control Channel (PDCCH), the terminal receives data in a Physical Downlink Shared Channel (PDSCH) after receiving the Downlink scheduling command, and after the terminal receives the data correctly, if the data is an ACK applied to the TCP layer by the TCP, the terminal keeps a continuous receiving state until a DRX inactivity timeout or receives a new PDCCH; if the DRX inactive timer is overtime, entering the DRX in a connection state; if a new PDCCH is received, receiving a PDSCH corresponding to the PDCCH; if the PDSCH includes a connection release message, the terminal releases the radio channel and exits from the connected state. If the connection release message is not contained, the terminal resets the DRX inactive timer and continues to wait for the timeout of the DRX inactive timer or a new PDCCH. The base station needs to send a connection release message on the PDSCH, wasting radio resources, and the terminal needs to receive the PDSCH, wasting the power of the terminal.
The mobile cellular internet of things technology has the following defects: the terminal needs a long time to receive a lot of data or waits for a long time to exit the connection state, which wastes a lot of air wireless resources and electric quantity of the terminal, especially for a lot of terminals in weak field signals.
Because the mobile cellular internet of things terminal is often in places where wireless signals are difficult to permeate, such as basements, shafts and the like, in order for the internet of things terminal to be capable of receiving and sending data, the mobile cellular internet of things communication system usually requires a high Maximum Coupling Loss (MCL) between a base station and the terminal; in weak electric field signals, because the signal-to-noise ratio is very low, the transmitting end usually repeatedly transmits the same signal for many times, and the receiving end combines a plurality of identical signals after receiving the signals and then decodes the signals. Although the repeated transmission can achieve the reception under the condition of low signal-to-noise ratio, the whole mobile cellular communication system occupies a lot of precious wireless resources, and a large amount of power is consumed for the terminal to receive signals.
Disclosure of Invention
In view of the above technical problems, an object of the present invention is to provide a method for quickly releasing a channel in a wireless internet of things communication system, which helps a terminal and a base station to quickly release the channel, thereby largely saving air radio resources, and simultaneously helps the terminal to quit a connection state more quickly, thereby saving electric quantity of the terminal.
A method for quickly releasing a channel in a wireless Internet of things communication system comprises the following steps after a terminal is connected with a base station:
step 1: the base station sends connection release downlink control information to the terminal through a downlink control channel of a physical layer;
step 2: the terminal receives connection release downlink control information;
and step 3: and the terminal directly releases the wireless channel after receiving the connection release downlink control information and exits from the connection state.
Preferably, after the terminal establishes a connection with the base station, the method for actively initiating a data connection for the terminal includes the following steps:
s1, a base station sends downlink control information:
s1-1, the base station sends the uplink transferring command in the downlink control information to the terminal through the physical layer downlink control channel;
s2, the terminal receives downlink control information:
s2-1, the terminal receives the up transfer order sent by the base station through the physical layer down control channel and then sends data in the physical layer up share channel;
s2-2, the terminal keeps the state of continuously receiving the downlink control information until the non-activated timing of the discontinuous reception is overtime or receives new downlink control information sent by a physical layer downlink control channel;
s3, a judging step:
if the non-continuous receiving non-activation timing is overtime, entering a non-continuous receiving mode in a connection state;
if the downlink control information which is newly received by the terminal and sent by the physical layer downlink control channel comprises connection release downlink control information, the terminal releases the wireless channel and exits from the connection mode;
if the downlink control information newly received by the terminal and sent by the physical layer downlink control channel does not contain connection release downlink control information, receiving a physical layer downlink shared channel corresponding to the physical layer downlink control channel; if the corresponding physical layer downlink shared channel contains a connection release message, the terminal releases the wireless channel and exits from the connection state; and if the corresponding physical layer downlink shared channel does not contain the connection release message, the terminal exits the discontinuous reception mode and enters the continuous reception mode.
Preferably, after the terminal establishes a connection with the base station, the method includes the following steps for the terminal that needs to receive data:
s1, a base station sends downlink control information:
s1-1, waiting for the base station to send the downlink transferring command in the downlink control information to the terminal through the physical layer downlink control channel;
s2, the terminal receives downlink control information:
s2-1, the terminal receives the downlink transfer command and then receives the data in the physical layer downlink shared channel;
s2-2, after the terminal receives the data correctly, if the transmission data is the transmission control protocol data, the terminal replies the confirmation character of the transmission control protocol layer to the base station;
s2-3, the terminal keeps the state of continuously receiving the downlink control information until the discontinuous reception non-activated timing is overtime or a new physical layer downlink control channel is received;
s3, a judging step:
if the non-continuous receiving non-activation timing is overtime, entering a non-continuous receiving mode in a connection state;
if the newly received physical layer downlink control channel contains connection release downlink control information, the terminal releases the wireless channel and exits from the connection state;
if the newly received downlink control information sent through the physical layer downlink control channel does not contain connection release downlink control information, receiving a physical layer downlink shared channel corresponding to the physical layer downlink control channel; if the corresponding physical layer downlink shared channel contains a connection release message, the terminal releases the wireless channel and exits from the connection state; if the connection release message is not contained, the terminal exits the discontinuous reception mode and enters the continuous reception mode.
Preferably, the connection release downlink control information is set in such a manner that a resource mapping field in the downlink control information is set to be resource allocation free.
Preferably, the setting mode of the connection release downlink control information is to set a field in the downlink control information to a certain reserved value or an invalid value.
Preferably, the connection release downlink control information is set in such a manner that a reserved field in the downlink control information is set to a specific value.
Preferably, the base station does not need to send the release message on the physical layer downlink shared channel after the physical layer downlink control channel sends the connection release downlink control information.
Preferably, when the base station and the terminal transmit the protocol layer data, the base station does not need to transmit the protocol layer acknowledgement character to the terminal in the physical layer downlink shared channel, but directly transmits the connection release downlink control information in the physical layer downlink control channel.
Advantageous effects
The invention provides a method for quickly releasing a channel in a wireless Internet of things communication system, which adopts a mode of sending connection release downlink control information to a certain terminal or some terminals on a physical layer downlink control channel, the terminals directly release the wireless channel after receiving the connection downlink control information so as to greatly save the air wireless resources of a mobile cellular communication system, and the terminals quit the connection state well when releasing the channel, simultaneously enable the terminals to quit the connection state more quickly and save the electric quantity of the terminals;
for a terminal which actively initiates data connection, the prior art needs a base station to send a physical layer downlink control channel and a downlink shared channel (wherein the channel release message), if the terminal is a TCP service, the process must wait for TCP layer ACK, but the method for quickly releasing the channel of the wireless Internet of things communication system provided by the invention only needs to send the physical layer downlink control channel (wherein the channel release command is hidden in the physical layer downlink control channel), and if the terminal is a TCP service, the process does not need to wait for the TCP layer ACK, thereby greatly improving the speed of releasing the channel;
for a terminal needing to receive data, the prior art needs to send a physical layer downlink control channel and a downlink shared channel (wherein the channel release message), but the invention provides a method for quickly releasing a channel of a wireless internet of things communication system, which only needs to send the physical layer downlink control channel (wherein a channel release command is hidden in the physical layer downlink control channel), thereby omitting the step of sending the release channel message by the physical layer downlink shared channel and greatly improving the rate of releasing the channel.
Drawings
Fig. 1 is a flowchart of a method for quickly releasing a channel in a wireless internet of things communication system;
fig. 2 illustrates a conventional method for releasing a channel when a terminal actively initiates a data connection;
fig. 3 is a conventional method for releasing a channel when a terminal receives data;
fig. 4 is a method for a wireless internet of things communication system to quickly release a channel when a terminal actively initiates a data connection;
fig. 5 is a method for quickly releasing a channel in a wireless internet of things communication system when a terminal receives data.
Detailed Description
The following further describes embodiments of the present invention with reference to the accompanying drawings:
example 1
As shown in fig. 4, when a terminal actively initiates a data connection, a method for quickly releasing a channel in a wireless internet of things communication system includes the following steps: after the terminal establishes connection with the base station, the terminal waits for the base station to send an Uplink transfer command in Downlink Control Information (DCI) to the terminal through a Physical Downlink Control Channel (PDCCH), the terminal initiates data in a Physical Uplink Shared Channel (PUSCH) after receiving the Uplink transfer command, and then the terminal keeps a continuous receiving state until a DRX inactive timer is overtime or receives a new PDCCH; if the DRX inactive timer is overtime, entering the DRX in a connection state; if the newly received PDCCH contains connection release downlink control information, the terminal releases a wireless channel and exits from a connection state (enters DRX or eDTX or a power saving mode). If the received PDCCH does not contain connection release downlink control information, receiving a PDSCH corresponding to the PDCCH; if the PDSCH includes a connection release message, the terminal releases the radio channel and exits the connected state (enters DRX or eDTX or power saving mode). If the PDSCH does not contain the connection release message, the terminal resets the DRX inactive timer and continues to wait for the timeout of the DRX inactive timer or a new PDCCH.
The connection release downlink control information includes but is not limited to the following ways:
1. the connection release of the downlink control information is implemented by setting a resource mapping domain in the downlink control information to be resource allocation free, and the resource allocation free may be implemented in many ways, for example, but not limited to, uplink or downlink resource block (resource block) or resource block group (resource block group) bit mapping (bit mapping), where the bit mapping is a series of bits, each bit corresponds to one resource block, setting a bit of the bit mapping to 0 indicates that the corresponding resource block or resource block group is not allocated to the terminal, and setting a bit of the bit mapping to 1 indicates that the corresponding resource block or resource block group is allocated to the terminal. Setting resource block (resource block) or resource block group (resource block group) bit mappings to all 0 is considered a connection release message.
2. The connection release downlink control information is implemented by setting a field (such as Modulation Coding Scheme (MCS), resource mapping field, etc.) in the downlink control information to a certain reserved value or invalid value,
3. the connection release downlink control information is obtained by setting a reserved field (e.g., padding bits) in the downlink control information to a specific value. In order to make the length of various DCIs reach a certain value, a plurality of padding bits (padding bits) are added after the valid field. Setting the padding bits to a certain value (e.g., without limitation, all 1 s) is considered connection release downlink control information;
4. the connection release downlink control information may also be various combinations in the above embodiments or one or more combinations with a certain value set in a certain field of the downlink control information in the above embodiments. Such as a resource indication value (resource indication value) is set to an invalid value and MCS is set to a reserved value and a New data indicator (New data indicator) is regarded as connection release downlink control information.
Compared with the conventional method shown in fig. 2, by using the connection to release the downlink control information, the base station does not need to transmit the connection release message on the PDSCH, and if the transmission is the TCP data, the base station does not need to send the TCP layer ACK, thereby saving wireless resources, and the terminal does not need to receive the PDSCH and wait for the DRX inactive timer to be overtime, thereby saving a large amount of electric quantity.
Example 2
As shown in fig. 5, when a terminal receives data, the method for quickly releasing a channel in a wireless internet of things communication system includes the following steps: after the terminal establishes connection with the base station, the terminal waits for a Downlink transfer command sent to the terminal by the base station through a Physical Downlink Control Channel (PDCCH), the terminal receives the Downlink transfer command and then receives data in a Physical Downlink Shared Channel (PDSCH), and after the terminal receives the data correctly, if the transmission data is TCP data, the terminal returns ACK of the TCP layer to the base station, and then the terminal keeps a continuous receiving state until a DRX inactive timer is overtime or receives a new PDCCH; if the DRX inactive timer is overtime, entering the DRX in a connection state; and if the newly received PDCCH contains connection release downlink control information, the terminal releases the wireless channel and exits from the connection state. If the newly received PDCCH does not contain the connection release downlink control information, receiving a PDSCH corresponding to the PDCCH; if the PDSCH includes a connection release message, the terminal releases the radio channel and exits from the connected state. If the connection release message is not contained, the terminal resets the DRX inactive timer and continues to wait for the timeout of the DRX inactive timer or a new PDCCH.
The connection release downlink control information may be implemented in the following manner but is not limited to the following manner:
1. one kind of connection release downlink control information is to set the resource mapping domain in the downlink control information as no resource allocation, and the downlink control information is regarded as a connection release message; the resource-free allocation can be implemented in many ways, for example, by but not limited to, a bit mapping (bit mapping) of an uplink or downlink resource block (resource block) or a resource block group (resource block group), where the bit mapping is a series of bits, each bit corresponds to one resource block, setting a bit of the bit mapping to 0 indicates that the corresponding resource block or resource block group is not allocated to the terminal, and setting a bit of the bit mapping to 1 indicates that the corresponding resource block or resource block group is allocated to the terminal. Setting resource block (resource block) or resource block group (resource block group) bit mappings to all 0 is considered a connection release message.
2. A connection release downlink control information is to set a field (such as Modulation Coding Scheme (MCS), resource mapping domain, etc.) in the downlink control information to a certain reserved value or invalid value; if the resource mapping field can be set to some kind of invalid resource allocation, but not limited to, the downlink control information is regarded as a connection release message; the invalid resource allocation may be implemented in many possible ways, such as by but not limited to setting a subcarrier indication field (subcarrier indication field) in the NB-IoT system DCI to a certain reserved value, and by but not limited to setting a resource indication value (resource indication value) in the LTE system DCI to an invalid value; if the MCS field in the downlink control information can be set to a reserved value or an invalid value by, but not limited to, setting the MCS field in the downlink control information to a reserved value or an invalid value;
3. another way to release the downlink control information is to set a reserved field (e.g., padding bits) in the downlink control information to a specific value. In order to make the length of various DCIs reach a certain value, a plurality of padding bits (padding bits) are added after the valid field. Setting the padding bits to a certain value (e.g., without limitation, all 1 s) is considered connection release downlink control information;
4. another implementation manner of the connection release downlink control information may also be various combinations of the above manners or combinations of one or more of the above embodiments and a certain field of the downlink control information set to a certain value. The connection release downlink control information is considered as if a resource indication value (resource indication value) is set to an invalid value and MCS is set to a reserved value and a New data indication (New data indicator) is set to 1.
Compared with the conventional method in fig. 3, by using the connection to release the downlink control information, the base station does not need to send the connection release message on the PDSCH, thereby saving wireless resources, and the terminal does not need to receive the PDSCH, thereby saving electric quantity.
Variations and modifications to the above-described embodiments may occur to those skilled in the art, which fall within the scope and spirit of the above description. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and variations of the present invention should fall within the scope of the claims of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.