CN102378296B - Method for carrying out frequency band switching in communication system - Google Patents

Abstract

The invention provides a method for carrying out frequency band switching in a communication system, wherein a control channel of the communication system takes up a part of frequency bands of a whole system bandwidth, and the control channel currently takes up a first frequency band. The method comprises the following steps that: a base station sends a control message to a terminal on a first frequency band and a second frequency band until a confirmation message fed back by the terminal is received; the control message instructs the terminal to switch the control channel from the first frequency band to the second frequency band; and the confirmation message instructs the terminal that the control message is received correctly. By using the method provided by the invention, the frequency band switching reliability of the terminal can be improved.

Description

A frequency band switching method in a communication system

technical field

The invention relates to the technical field of communication, in particular to a frequency band switching method in a communication system.

Background technique

In a Long Term Evolution (LTE) communication system, control information is transmitted on the entire system bandwidth, and service information is transmitted on a part of the system bandwidth. Before the base station and the terminal communicate, the base station will allocate some frequency bands of the entire system bandwidth to the terminal, and then the terminal uses these frequency bands to send and receive business information. When the fading of service information transmitted on these frequency bands is large, the base station sends control information to the terminal to notify the terminal to switch to other frequency bands with better performance, so as to ensure that the communication between the base station and the terminal always maintains a good performance.

FIG. 1 is a flowchart of a method for frequency band switching in an LTE system.

As shown in Figure 1, the method includes:

Step 101, the base station sends a control message of frequency band switching to the terminal on the entire system bandwidth.

Step 102, the base station exchanges service information with the terminal on the switched frequency band.

Step 103, the base station judges whether the exchanged service information meets the expected result, if yes, returns to step 102, otherwise, returns to step 101.

The expected result refers to the result of exchanging service information between the base station and the terminal after the terminal correctly switches to the corresponding frequency band according to the control message sent by the base station.

On the terminal side, the terminal receives the frequency band switching message sent by the base station within the entire system bandwidth. If the switching message is received, it switches to the corresponding frequency band, and uses the switched frequency band to receive and send service information. If the above handover message is used, the service information is received and sent on the original frequency band.

Since the control channel of the LTE system occupies the entire system bandwidth, the terminal can receive the control information sent by the base station no matter which frequency bands the service information of the terminal is sent and received on.

In some systems, due to limitations of hardware and other conditions, the terminal is required to be as simple as possible in order to simplify the processing flow and save costs. For the purpose of simplification, the terminal can only work in a narrow spectrum range, and both control information and business information are sent and received in this spectrum range, that is, the control channel and traffic channel only occupy part of the entire system bandwidth. When the frequency band occupied by the control channel and traffic channel of the terminal has a large fading, the base station needs to send a frequency band switch message to the terminal to notify the terminal to switch to another frequency band to send and receive service information and control information, and the base station will also send and receive service information and control information on the other frequency band Send and receive service information and control information, see Figure 2 for details.

Fig. 2 is a flowchart of a handover method in the prior art when a control channel occupies a part of the entire system bandwidth.

As shown in Figure 2, the method includes:

In step 201, the base station sends a control message of frequency band switching to the terminal on the currently occupied frequency band.

Step 202, the base station sends control information and service information to the terminal on the frequency band after switching, and receives service information of the terminal on the frequency band after switching.

In this step, if the terminal receives the control message correctly, it performs frequency band switching, and exchanges control information with the base station on the switched frequency band.

However, if the terminal fails to receive the control message correctly, the terminal will still send and receive service information on the original frequency band.

It can be seen that when the control channel of the communication system occupies part of the frequency band of the entire system bandwidth, if the terminal fails to correctly receive the frequency band switching control message sent by the base station for the first time, it will cause the terminal to be unable to receive the frequency band switching control message sent again by the base station. As a result, the reliability of frequency band switching by the terminal is low.

Moreover, since the terminal cannot reliably switch the frequency band, the terminal will send and receive service information on the original frequency band, while the base station will send and receive service information on the switched frequency band, and the communication system cannot normally perform information transmission.

Contents of the invention

In view of this, the present invention provides a frequency band switching method in a communication system, so as to improve the reliability of a terminal performing frequency band switching.

A frequency band switching method in a communication system, in which a control channel of the communication system occupies a part of the entire system bandwidth, and the control channel currently occupies a first frequency band, the method comprising:

The base station sends a control message to the terminal on the first frequency band and the second frequency band until receiving a confirmation message fed back by the terminal;

The control message instructs the terminal to switch the control channel from the first frequency band to the second frequency band; the confirmation message indicates that the terminal has correctly received the control message.

It can be seen from the above technical solution that when the control channel of the communication system occupies part of the frequency band of the entire system bandwidth, the base station sends a control message for frequency band switching to the terminal on the frequency band currently occupied by the control channel and the target frequency band until receiving the said The confirmation message fed back by the terminal. Since the base station does not only send the control message to the terminal on the currently occupied frequency band or only on the target frequency band, but sends the control message to the terminal on both the currently occupied frequency band and the target frequency band, no matter the Whether the terminal is working in the currently occupied frequency band or the target frequency band can receive the control message, and if the base station does not receive the confirmation message fed back by the terminal after sending the control message, the base station will again The control message is sent to the terminal until the confirmation message fed back by the terminal is received, which further improves the reliability of the frequency band switching by the terminal.

Description of drawings

FIG. 1 is a flowchart of a method for frequency band switching in an LTE system.

Fig. 2 is a flowchart of a handover method in the prior art when a control channel occupies a part of the entire system bandwidth.

Fig. 3 is a detailed flowchart of the base station side in the frequency band switching method in the communication system provided by the present invention.

Fig. 4 is a detailed flowchart of the terminal side in the frequency band switching method in the communication system provided by the present invention.

Detailed ways

The frequency band switching method provided by the invention is applied in a communication system in which the control channel occupies part of the frequency band of the entire system bandwidth. Specifically, the frequency band occupied by the terminal before the frequency band switching is recorded as the first frequency band, and the frequency band occupied by the terminal after the frequency band switching is recorded as the second frequency band, then the base station reports to the terminal on the first frequency band and the second frequency band sending a control message until receiving an acknowledgment message fed back by the terminal, wherein the control message instructs the terminal to switch the control channel from the first frequency band to the second frequency band, and the acknowledgment message indicates that the terminal has correctly received the control message.

In the processes shown in FIG. 3 and FIG. 4 , the frequency band occupied by the terminal before the frequency band switching is recorded as the first frequency band, and the frequency band occupied by the terminal after the frequency band switching is recorded as the second frequency band.

Fig. 3 is a detailed flowchart of the base station side in the frequency band switching method in the communication system provided by the present invention.

As shown in Figure 3, the process includes:

Step 301, the base station sends a control message for performing frequency band switching to the terminal on the first frequency band.

Wherein, the control message instructs the terminal to switch the control channel from the first frequency band to the second frequency band, and the control message may further instruct the terminal to switch the traffic channel from the first frequency band to the second frequency band.

Step 302, the base station receives a confirmation message fed back by the terminal on the first frequency band.

Step 303, judging whether the base station has received the confirmation message within a predetermined time period, if yes, execute step 307, if not, execute step 304.

Step 304, the base station sends the control message to the terminal on the first frequency band and the second frequency band.

Step 305, the base station receives the confirmation message on the first frequency band and the second frequency band.

Step 306, judge whether the base station receives the confirmation message on the first frequency band or the second frequency band, if yes, execute step 307, if not, return to step 305.

Step 307, the base station switches to the second frequency band to communicate with the terminal.

The method shown in Figure 3 is that the base station first sends the control message only on the first frequency band, and then sends the control message on the first frequency band and the second frequency band after receiving no confirmation message fed back by the terminal within a predetermined period of time. , in order to facilitate a unified process and simplify operations at the base station, the base station may send control messages to the terminal on the first frequency band and the second frequency band each time.

Fig. 4 is a detailed flowchart of the terminal side in the frequency band switching method in the communication system provided by the present invention.

As shown in Figure 4, the process includes:

In step 401, the terminal receives a control message for frequency band switching sent by the base station.

In step 402, the terminal feeds back an acknowledgment message that the control message has been received to the base station.

Wherein, if the terminal has not switched to the second frequency band, feed back the confirmation message to the base station on the first frequency band, and if the terminal has switched to the second frequency band, then send the confirmation message to the base station on the second frequency band The base station feeds back the confirmation message.

After both the base station and the terminal complete the frequency band switching operation, the base station and the terminal can exchange service information on the second frequency band. Specifically: after the base station receives the confirmation message fed back by the terminal, it can send a scheduling command to the terminal on the second frequency band, and the terminal exchanges service information with the base station on the second frequency band according to the scheduling command; or, the terminal is feeding back After the confirmation message, if the terminal receives other control information sent by the base station that is different from the last time, or does not receive the same control message as the last received control message within a predetermined period of time, it means that the base station has After receiving the confirmation message fed back by the terminal, and the base station has also switched to the second frequency band to work, the terminal and the base station can exchange service information on the second frequency band; or, after the base station receives the confirmation message, Waiting for a predetermined period of time so as to correspond to the time slot used by the terminal for service transmission, and exchanging service information with the terminal on the second frequency band.

Through the present invention, when the terminal works in a narrowband communication system, the reliability of frequency switching by the terminal can be guaranteed with relatively small control signaling overhead without increasing the complexity of the system.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (7)

1. the method for carrying out frequency band switching in a communication system, the control channel of this communication system takies the partial-band of whole system bandwidth, and current first frequency band that takies of control channel is characterized in that, and the method comprises:

The base station transmits control message to terminal on the first frequency band and the second frequency band, until receive the confirmation message of described terminal feedback;

Described control message indicating terminal switches to described the second frequency band with control channel from described the first frequency band; Described acknowledge message indicates this terminal correctly to receive described control message;

Wherein, described base station transmits control message to terminal on the first frequency band and the second frequency band and comprises:

The base station sends described control message to terminal on described the first frequency band, receive described acknowledge message at described the first frequency band, if the base station is not received described acknowledge message within a predetermined period of time, the base station sends described control message to terminal on described the first frequency band and described the second frequency band.

2. method according to claim 1, is characterized in that,

The base station receives described acknowledge message on described the first frequency band and described the second frequency band.

3. method according to claim 1, is characterized in that, the method further comprises:

After the described acknowledge message of terminal feedback is received in the base station, switch to described the second frequency band and described terminal and communicate.

4. method according to claim 1, is characterized in that,

After terminal receives described control message, if terminal does not also switch to described the second frequency band, on described the first frequency band to the described acknowledge message of base station feedback, if terminal has switched to described the second frequency band, on described the second frequency band to the described acknowledge message of base station feedback.

5. the described method of arbitrary claim of according to claim 1 to 4, is characterized in that, the further indicating terminal of described control message switches to described the second frequency band with Traffic Channel from described the first frequency band, and the method further comprises:

After the confirmation message of terminal feedback is received in the base station, send dispatching command to terminal on described the second frequency band, terminal according to this dispatching command on described the second frequency band with base station interactive service information.

6. the described method of arbitrary claim of according to claim 1 to 4, is characterized in that, the further indicating terminal of described control message switches to described the second frequency band with Traffic Channel from described the first frequency band, further carries dispatching command in described control message; The method further comprises:

Terminal is after the described acknowledge message of feedback, if terminal received other control information different with last time that the base station sends or do not received within a predetermined period of time the identical control message of described control message of receiving with the last time, terminal and described base station business information alternately on described the second frequency band.

7. method according to claim 6, is characterized in that, the method further comprises:

After described acknowledge message is received in the base station, directly send the control information of other different with last time to terminal on described the second frequency band, perhaps wait for predetermined amount of time, on described the second frequency band with the terminal interaction business information.

Images