KR20110090305A - Method for managing cooperative network in cognitive radio network assisted satellite - Google Patents

Abstract

PURPOSE: A satellite and cooperation network management method in a wireless recognition communication network is provided to optimize wireless resource allocation using information of wireless recognition network user through a cooperation network management. CONSTITUTION: A user(104) and a master user(105) of a wireless recognition system coexist within a communications region of a satellite. A transmission unit of a wireless recognition system is able to communicate sensing information and location data(106) with the satellite. The transmission unit of a wireless recognition system has up and down link(108). A transmission power of the wireless recognition system is allocated using the sensing and the location information.

Description

Method for managing cooperative network in cognitive radio network assisted satellite}

The present invention relates to a radio communication system based on Cognitive Radio, and more particularly, to a cooperative network management method using satellite communication for a radio aware communication system.

Currently, most communication systems communicate using licensed fixed bands. However, because of the large frequency and temporal variation in the use of the spectrum, it causes spectrum inefficiency. In order to solve this problem of inefficient use of spectrum, a proposed system is a wireless cognitive system.

Such a wireless recognition system has been proposed as an alternative to efficiently share spectrum in response to the current rapidly increasing spectrum demand trend.

In December 2003, the Federal Communications Commission (FCRM) 's Notice of Proposed Rule Making (NPRM) mentioned the possibility of common frequency use, and efforts to develop it into a realistic system resulted in a standardization organization called IEEE802.22.

Currently, standardization and development of Cognitive Radio is being activated, but there are many problems to be solved because it is still in the early stages, and the composition technologies have not been decided yet.

In particular, in the operation of the wireless recognition system, since the wireless recognition system should be operated so as not to affect the performance of the main user, in a system that does not share the information of the wireless recognition user, transmission quality may be guaranteed depending on the situation of the user of the wireless recognition system. You may not be able to. In addition, as the number of users of the wireless cognitive system increases, the interference between the wireless cognitive users increases in addition to the interference to the main user.

The present invention provides a method for cooperative network management with a satellite and a wireless recognition system that can share information between users of the wireless recognition system.

In addition, the present invention provides a cooperative network management method between the satellite and the wireless cognitive system to share information between users of the wireless cognitive system so that the transmission quality of the wireless cognitive system through an efficient resource management method for optimizing the allocation of radio resources. Improve performance

The method for managing a cooperative network with satellites in a wireless cognitive communication network according to an embodiment of the present invention optimizes radio resource allocation using information of a wireless cognitive user through cooperative network management with satellite communication for wireless resource allocation of a wireless cognitive system. In this way, the transmission power and the use channel are allocated using the sensing and location information of the radio-aware user.

In one aspect of the present invention, the wireless recognition transmitter and the satellite directly communicate the sensing information and location information of the wireless recognition user may share the information of the wireless recognition user.

In addition, in one aspect of the present invention, the transmission power of the radio-aware user may be allocated using the sensing and location information of the radio-aware user.

In addition, in an aspect of the present invention, the use channel of the wireless aware user may be allocated using the sensing and location information of the wireless aware user.

In another aspect of the present invention, the method may include updating the sensing and location information of the user, calculating a possible output power for each user, determining whether the calculated output power exceeds a maximum output power, If the calculated output power exceeds the maximum output power, setting the output power to the maximum output power, determining whether the maximum output power exceeds an interference threshold and the maximum output power is the If the interference threshold is exceeded, the method may include calculating a possible output power by the water filling method and allocating the calculated output power.

In addition, in one aspect of the present invention, the wireless cognitive transmitter may transmit sensing and location information of each wireless cognitive user to the satellite through an uplink to the satellite.

In addition, in one aspect of the present invention, the satellite may calculate the maximum possible transmission power that can be used by each of the radio-aware users using the sensing and location information of the radio-aware user.

In addition, in one aspect of the present invention, the step of updating the output power and the allocation channel of the user, determining whether the channels of the existing wireless recognition user and the comparison target wireless user is the same, and if the channels are not the same, Calculating interference between the users, determining whether the calculated interference level is lower than a maximum allowable co-channel interference level, and if lower than the co-channel interference level, Reassignment to the same channel.

In another aspect of the present invention, the method may further include checking whether channel reassignment is completed for all the radio-aware users.

In addition, in one aspect of the present invention, the step of confirming that channel reassignment is completed for all the radio-aware users is performed when the channels of the existing radio-aware user and the target radio-aware user are the same or more than the calculated co-channel interference level. If not low, it may be checked whether channel reassignment is completed for all the radio-aware users.

According to the present invention, unlike the method of not knowing the radio recognition user mutual information, the number of channels required through output power, channel allocation, and blocking probability based on the sensing and distance information of the radio recognition user based on this information. ) To accommodate more users of the wireless recognition system.

In addition, according to the present invention, there is an effect of improving the performance of the radio recognition system by predicting and assigning the output power available to the radio recognition user.

1 is a diagram illustrating an example of a wireless cognitive communication system to which a cooperative network management method according to the present invention is applied.
2 is a flowchart illustrating a power allocation process using sensing and location information of a wireless cognitive user according to the present invention.
3 is a flowchart illustrating a channel allocation process using sensing and location information of a wireless cognitive user according to the present invention.
FIG. 4 is a graph illustrating a comparison of the blocking possibility performance of a cooperative network management scheme with satellite communication and a wireless cognitive system that does not share mutual information among wireless cognitive users.

In the cooperative network management according to the present invention, the user of the radio recognition system can share information necessary for each resource allocation and use it for resource allocation.

In the non-cooperative network management according to the present invention, the user of the radio recognition system performs resource allocation without sharing information required for each resource allocation.

In the present invention, the sensing information is information related to sensing such as channel frequency and transmission power of the user of the radio recognition system.

In the present invention, the location information is information about the location of the user of the radio recognition system and the transmitter of the radio recognition system.

In the present invention, the wireless cognitive system transmitter is a wireless cognitive system having uplink and downlink that can communicate with a wireless cognitive system receiver and directly communicate with a satellite.

In the present invention, the primary user is a user of the licensed spectrum allocated to the operator base station of the existing system.

The present invention considers the following matters to provide a cooperative network management function with a satellite in a wireless environment of a radio recognition technology.

First, in the wireless environment of the wireless recognition technology, frequency resources are not allocated to each operator, such as a portable Internet, a CDMA network, and a wireless Internet, but must share frequency resources allocated to a base station of another existing communication system.

Second, in the wireless environment of the radio recognition technology, it should be possible to exchange information directly without a special control channel for information exchange between the radio recognition transmitter and the satellite. Therefore, the information message should be able to be transmitted in synchronization with at least one uplink or downlink or channel.

Hereinafter, a cooperative network management method of a satellite communication and a wireless cognitive communication system according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 illustrates a system model to which cooperative network management of a satellite 101 and a radio recognition system is applied.

Referring to FIG. 1, a user 104 and a main user 105 of a radio recognition system coexist in a satellite's communication area. Here, the ellipse portion 103 indicated by the shade indicates the communication area of the radio recognition system and the ellipse portion 102 indicated by the dotted line indicates the communication area of the satellite. The transmitter 107 of each radio recognition system has an uplink and a downlink 108 that can send and receive direct sensing information and location data 106 with a satellite.

2 is a flowchart illustrating a transmission power allocation process using sensing and location information of a wireless cognitive user in cooperative network management.

Referring to FIG. 2, in the wireless recognition system, the allocated transmission power of the wireless recognition user should not exceed the maximum transmission power of the wireless recognition user as shown in Equation 1.

[Equation 1]

In addition, in the wireless recognition system, the interference received by the main user due to the radio recognition user, as shown in Equation 2, should not exceed the interference threshold of the main user.

[Equation 2]

Therefore, it is important to efficiently allocate the transmission power of each radio-aware user within a range not exceeding the interference threshold of the main user. This interference limit can be expressed as follows.

In the cooperative network management method proposed by the present invention, the radio recognition users can share information with each other by using satellite communication, so that transmission power can be allocated to minimize the interference received by the main user due to the radio recognition users.

First, the radio-aware transmitter transmits sensing and location information 201 of each radio-aware user to the satellite via an uplink to the satellite.

The satellite then uses this information to calculate the maximum possible transmit power available to each radio aware user (202).

The satellite checks (203) whether the calculated value of the transmit power fits the radio recognition system.

If the calculated transmittable power is greater than the maximum transmit power available to the wireless aware user, the transmit power of the wireless aware user is allocated to transmit at the maximum transmit power instead of the calculated transmitable power (204).

If less than the maximum transmit power, transmit power is allocated to transmit at the calculated transmittable power. After this process, the interference level affecting the main user from the thus allocated transmission power is predicted (205). If the interference level is greater than the interference threshold that the main user can tolerate, the power is recalculated and reallocated by the water filling method (206).

The water filling method may be expressed as Equation 3 below.

&Quot; (3) "

If the interference level is less than the interference threshold, the allocated transmission power is maintained (207). When this process is finished, the transmission power allocation process ends. The transmission power thus determined is transmitted to the respective radio-aware transmitters through the downlink of the satellite to allocate transmission power.

3 is a flowchart illustrating a channel allocation process using sensing and location information of a radio aware user in cooperative network management.

Referring to FIG. 3, when the transmission power allocation process is completed, the satellite updates the allocated transmission powers and channels of all radio-aware users through the uplink of the radio-aware transmitter (301). The updated information is used to find a radio aware user having a different channel from each radio aware user (302), and then calculate interference (303) between radio aware users having different channels. It is then checked if this interference level satisfies the constraints of the radio recognition system (305). If this interference level is lower than the Co-channel interference (CII) level, both are reassigned to the same channel (306), and if it is high, maintain its own channel. This process is repeated until it applies to all users of the radio recognition system (304).

Such channel allocation can lower the effective frequency reuse rate and reduce the blocking probability compared to a system that does not share information of the radio-aware users.

Methods according to an embodiment of the present invention can be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer readable medium. The computer readable medium may include program instructions, data files, data structures, etc. alone or in combination. Program instructions recorded on the media may be those specially designed and constructed for the purposes of the present invention, or they may be of the kind well-known and available to those having skill in the computer software arts.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

101: satellite
102: satellite communication area
103: communication area of the radio recognition system
104: user of a wireless cognitive system
105: main user
106: sensing information / location
107: wireless recognition system
108: phase, downlink

Claims (10)

In order to optimize radio resource allocation of the radio recognition system, the transmission power and the use channel are generated by using the sensing and location information of the radio recognition user in a manner of optimizing radio resource allocation using information of the radio recognition user through cooperative network management with satellite communication. How to assign, cooperation network management method. The method of claim 1,
And sensing information and location information of the radio recognition user directly communicating with a radio recognition transmitter and a satellite to share information of the radio recognition user. The method of claim 1,
And allocating transmission power of the radio-aware user by using the sensing and location information of the radio-aware user. The method of claim 1,
And assigning a use channel of the wireless aware user using the sensing and location information of the wireless aware user. The method of claim 1,
Updating the sensing and location information of the user;
Calculating a possible output power for each user;
Determining whether the calculated output power exceeds a maximum output power;
If the calculated output power exceeds the maximum output power, setting the output power to the maximum output power;
Determining whether the maximum output power exceeds an interference threshold; And
Calculating a possible output power by a water filling method when the maximum output power exceeds the interference threshold; And
Allocating the calculated output power
Including, cooperation network management method. The method of claim 2,
The radio-cognitive transmitter,
And transmitting the sensing and location information of each radio-aware user to the satellite through an uplink to the satellite. The method of claim 6,
The satellite,
And calculating the maximum possible transmission power available to each of the radio-aware users using the sensing and location information of the radio-aware user. The method of claim 1,
Updating the user's output power and assigned channel;
Determining whether a channel of an existing wireless recognition user and a comparison target wireless recognition user are the same;
Calculating interference between the users when the channels are not the same;
Determining whether the calculated interference level is lower than a maximum allowable cochannel interference level;
Reassigning to the same channel as the channel of the existing radio-aware user when the co-channel interference level is lower than
Including, cooperation network management method. The method of claim 8,
And confirming that channel reallocation has been completed for all radio-aware users. 10. The method of claim 9,
The step of confirming that channel reassignment for all the radio-aware users is completed,
If the channel of the existing radio recognition user and the comparison target radio recognition user is the same or not lower than the calculated co-channel interference level, confirming whether channel reassignment is completed for all the radio recognition users.

Images