KR20060039580A - Method and system for operating smart antenna in sleep mode of personal subscriber terminal at portable internet system - Google Patents

Abstract

The present invention relates to a method and system for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system.

According to the present invention, a Personal Subscriber Station (PSS) (hereinafter referred to as "PSS") in a sleep mode is periodically connected to a Radio Access Station (RAS). A method for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system when performing ranging (Periodic Ranging), (a) ranging code and training sequence from the PSS Receiving a ranging request message including a sequence); (b) calculating a weight vector for beamforming using the distortion degree of the training sequence; And (c) determining a beam pattern of the smart antenna using the weight, and a method for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system, and a system for performing the same. It is about.

According to the present invention, even in the sleep mode of the terminal, it is possible to provide an optimal beamforming to the user by using real-time signal processing technology according to the position of the user.

Mobile Internet, Smart Antenna, Sleep Mode, Beam Shaping, Weighting, Training Sequence, Location

Description

TECHNICAL FIELD AND SYSTEM FOR OPERATING SMART ANTENNA IN SLEEP MODE OF PERSONAL Subscriber Terminal at Portable Internet System

1 is a view for showing an example of the sleep-mode operation,

2 is a view illustrating beam patterns of a fixed beam smart antenna and an adaptive beam smart antenna;

3 is a view showing applicability of a fixed beam smart antenna and an adaptive beam smart antenna;

4 illustrates an example of a problem when operating an adaptive array antenna that is a type of smart antenna in a sleep mode;

5 is a block diagram schematically illustrating a system for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system according to an embodiment of the present invention;

6 is a view schematically showing a periodic ranging procedure according to a preferred embodiment of the present invention;

7 illustrates an example of a ranging request message including a training sequence;

8 is a flowchart schematically illustrating a process for operating a smart antenna in a sleep mode of an individual subscriber terminal in a portable internet system according to a preferred embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

500: PSS 510: RAS

520: ACR 530: HA

540: AAA server 550: IP network

560: the Internet

The present invention relates to a method and system for operating a smart antenna in a sleep mode of a personal subscriber station in a portable Internet (PI: Portable Internet or WiBro: Wireless Broadband) system. More specifically, a personal subscriber station (PSS: hereinafter referred to as 'PSS') in a sleep mode may be connected to a radio access station (RAS). When performing periodic ranging, the RAS sends a ranging request message including a ranging code and a training sequence from the PSS to the RAS. The present invention relates to a method and system for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system operating a smart antenna by determining an antenna beam pattern.

With the rapid development of communication technology and development of various contents, various wireless communication services using a wireless network have been provided. The most basic wireless communication service is a wireless voice call service that provides a voice call to a mobile terminal user wirelessly, which can provide a service regardless of time and place. In addition, while providing a text message service to complement the voice call service, a wireless Internet service has recently emerged to provide an Internet communication service to a user of a mobile communication terminal through a wireless communication network.

As such, due to the development of mobile communication technology, a service provided by a code division multiple access (CDMA) mobile communication system transmits not only a voice service but also data such as circuit data and packet data. Is developing into a multimedia communication service.

In recent years, with the development of information and communication, IMT-2000 (International Mobile Telecommunication 2000), a third generation mobile communication system that has been standardized by ITU-R (for example, CDMA2000 1X, 3X, EV-DO, WCDMA (WideBand CDMA)) Etc.) are commercially available. IMT-2000 is a CDMA 2000 1X, 3X, EV-DO, WCDMA (WideBand CDMA), etc., which is used in IS-95A and IS-95B networks by using the IS-95C network that has evolved from the existing IS-95A and IS-95B networks. It is a service that can provide wireless Internet at a transmission speed of up to 144 Kbps, much faster than the supportable data transfer rate of 14.4 Kbps or 56 Kbps. In particular, by using IMT-2000 service, it is possible to provide various multimedia services (AOD, VOD, etc.) at higher speed as well as improving existing voice and WAP service quality.

Currently, the wireless Internet using technology is widely used as the third generation cellular system based on the mobile phone network described above and the wireless local access network (WLAN) based on IP-based packet transmission.

Existing cellular systems support high mobility and handoff, guarantee data rates required for voice calls, and additionally support packet data services. However, the existing mobile communication system has a high base station construction cost and high wireless Internet usage fee, and a small screen size of the mobile communication terminal has limited content that can be used, and provides sufficient transmission speed for packet data service. There is a limit to guarantee.

On the other hand, WLAN guarantees superior data transmission rate compared to cellular systems, but there is a problem in mobility due to radio interference and limitation in provision of public service due to problems such as narrow coverage.

In this regard, a portable internet service system, which has a transmission speed comparable to that of a WLAN, supports cellular system mobility and handoff, and provides high-speed wireless Internet service at a low price.

The portable Internet service, referred to as the 3.5th generation, adopts orthogonal frequency division multiple access (OFDM) and time division duplexing (TDD), which are core technologies of the next generation. In addition, standardization work is currently underway to employ technologies such as Adaptive Modulation Coding (AMC), Multi Input Multi Output (MIMO), and Smart Antenna to efficiently operate radio resources.

IP packet traffic to be provided by portable Internet services is generally bursty. In other words, IP packet traffic generates much data only when necessary, whereas circuit-based services represented by voice calls continue to occupy the allocated wireless channel until the service is terminated after connecting to the server. There is this. Therefore, in consideration of such a bursty characteristic, the portable Internet service adopts a sleep-mode that reduces power waste in a section where no data is generated.

1 is a diagram illustrating an example of sleep-mode operation.

Sleep-mode based on the IEEE 802.16e standard is a technology used to reduce the power consumption of the terminal, as opposed to the awake mode, which is a general mode for exchanging messages between the base station and the terminal. To prevent this, the terminal and the base station do not communicate during the period in which packet data does not occur.

In order for the terminal to enter the sleep-mode, it must send a MOB-SLP-REQ message 100 to the base station and request permission. At this time, the MOB-SLP-REQ message 100 includes a basic CID (Connection ID) of the terminal. Next, the base station sends a response message 110 corresponding to the MOB-SLP-REQ message 100 from the base station, where the response message includes the Sleep ID and the parameters of FIG. 1, and the terminal uses this information. You will enter Sleep- mode.

As shown in FIG. 1, two types of intervals exist in the sleep-mode. Sleep-interval (120) and Listening-interval (130) is that, Sleep-interval (120) is a period from the time the terminal enters the Sleep-mode to return to Awake-mode Sleep-interval during Sleep-mode 120 increases exponentially and can adjust the maximum and minimum limits. The listening-interval 130 is a period for determining whether the synchronized terminal stays in sleep-mode or returns to awake-mode by transmitting downlink information to the terminal in the awake state.

This sleep-mode concept is a good way to solve the power problem of the terminal by preventing power waste. However, even during this sleep-mode, channel conditions continue to change regardless of the presence or absence of data to be transmitted. Therefore, the base station should periodically range during the listening-interval 130 so that a packet can be transmitted to the terminal at any time.

On the other hand, there are three types of antenna installation in the mobile base station. Sector antenna, fixed multibeam antenna, and adaptive array antenna. Among these, adaptive array antennas, also called intelligent antennas or smart antennas, in the mobile communication field began with the concept of adaptive antennas in the mid-1950s and radars in the 1960s and 70s. It began to be developed as an adaptive antenna system for sonar and aircraft, and the theory and practice were summarized in the 1980s. In the 1990s, multi-beam antennas were introduced for satellite communication applications, and they began to be nicknamed 'smart' antennas around 1995, when research and development of wireless terrestrial mobile communication technologies were active.

Unlike the case of combining multipath signals using two conventional diversity antennas, smart antenna technology uses an array antenna and advanced high-performance digital signal processing technology to control the adaptive antenna beam pattern according to the change of RF signal environment. It is an advanced signal processing and antenna technology that enables maximum transmission and reception performance and capacity. The basic concept of smart antenna technology in a mobile communication base station system is that in the existing base station, radio signals are communicated by omnidirectional sector beam pattern using two diversity antennas per sector. It is a concept born from the concept that it is supposed to receive. In other words, instead of forming a radiation beam in all directions, by radiating a directional beam only to a corresponding subscriber, it is possible to increase the communication quality and system channel capacity by minimizing the effect of signal interference to all subscribers operating in the sector.

It is speculated that this concept was first attempted at Bell Lab. For application to mobile communication, and is now entering the practical stage beyond the concept verification stage. The development of a practical smart antenna system has been made possible since the development of low-cost, high-speed signal processors, general purpose processors, and powerful beamforming algorithms. In other words, the state-of-the-art signal processing technology is bonded to the antenna technology to see the result. Therefore, the mobile communication base station to which the smart antenna technology, which is referred to as the digital adaptive directional beamforming antenna technology, is applied to the spatial filter to increase or remove the signal based on the direction in which the signal incident on each element of the array antenna is introduced. It may be referred to as a smart base station system that provides a function of a filter. The smart base station system, unlike the conventional base station system, in which the total transmit power transmitted from the base station to the terminal has a very small effective receive power for a mobile phone or terminal subscriber, adaptively optimally combines the received signals by beam-directed control to prevent interference signals. It can be said that the system provides the optimum received signal power to the subscriber by greatly reducing the level.

2 is a diagram illustrating beam patterns of a fixed beam smart antenna and an adaptive beam smart antenna.

The smart antenna may be classified into various types according to the reference. However, when the smart antenna is classified according to the beam forming method, there may be a fixed beam smart antenna and an adaptive beam smart antenna.

The fixed beam selection method means that the beam pattern of the antenna is fixed, and the adaptive beam selection method means that the pattern of the antenna may change depending on time or surrounding environment.

As shown in FIG. 2, the fixed beam smart antenna has a feature that the adaptive beam smart antenna can form a beam pattern of a type appropriate to the user, as compared with the fixed beam pattern.

3 is a diagram illustrating the applicability of a fixed beam smart antenna and an adaptive beam smart antenna.                         

As shown in FIG. 3, the adaptive beam smart antenna may be more intelligently adapted to the environment than the fixed beam smart antenna. On the other hand, the fixed beam smart antenna may result in a decrease in signal reception performance when the user is positioned between the antenna pattern and the pattern. That is, the adaptive beam method shows superior performance compared to the fixed beam method, but requires a lot of cost and technology.

Since the fixed beam smart antenna is used to find the strong direction of the signal and transmit and receive using the beam in that direction, only the power measurement and the direction tracking can be performed, so that an algorithm is not necessary. However, in order to implement a scheme using an adaptive beam smart antenna, an algorithm for forming and directing an appropriate beam in a direction of a desired subscriber is required.

However, when the smart antenna scheme is used in the portable internet system, the biggest problem is that the real-time user tracking function of the smart antenna is impossible when the portable internet terminal enters the sleep mode. The reason for losing the real-time user tracking function when the portable internet terminal enters the sleep mode is that the mobile terminal includes the base station and the ranging signal (including terminal location information, etc.) when the terminal is awake. User information can be tracked at any time by periodic or necessity at any time by periodic or necessity. However, in sleep-mode, the terminal can be connected to the base station and the lane except for the Listening Interval period. Because you can't send and receive signs. Therefore, the base station that does not receive such a ranging signal is not aware of the position movement change of the terminal during the sleep-mode, so it is impossible to determine the position of the terminal, the base station is unable to form a beam based on the position of the terminal.

4 illustrates an example of a problem when operating an adaptive array antenna that is a type of smart antenna in a sleep mode.

If the user of the portable Internet service moves while receiving the portable Internet service, and the terminal is not used for a predetermined time in the middle of the movement, the terminal is turned off without generating packet data, and the terminal and the base station are mutually promised. After a certain OFF period, it goes to sleep-mode. When the terminal is switched to the sleep mode, the base station cannot know the change of the position movement of the terminal during the sleep mode, and thus cannot determine the position of the terminal. The biggest feature of the adaptive array antenna is that it provides the optimal beamforming to the user by using real-time signal processing technology according to the user's location. Thus, if the wireless channel information of the terminal is not updated, the packet data to be suddenly sent from the base station to the terminal There is a problem in that it is impossible to give the best beam forming when the.

In order to solve this problem, the present invention provides that a Personal Subscriber Station (PSS: hereinafter referred to as a 'PSS') in a sleep mode is a Radio Access Station (RAS: RAS). When performing periodic ranging and periodic ranging, the training received by the RAS by transmitting a ranging request message including a ranging code and a training sequence from the PSS to the RAS. An object of the present invention is to provide a method and system for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system operating the smart antenna by determining a beam pattern of the smart antenna using a sequence.

In order to achieve the above object, the present invention provides a personal subscriber station (PSS) in a sleep mode (hereinafter referred to as a 'PSS') to a radio access station (RAS). RAS ') and the periodic ranging (Periodic Ranging), the method for operating the smart antenna in the sleep mode of the personal subscriber station in the portable Internet system, (a) ranging code (Ranging) from the PSS Receiving a ranging request message including a code) and a training sequence; (b) calculating a weight vector for beamforming using the distortion degree of the training sequence; And (c) determining a beam pattern of the smart antenna by using the weights. The method for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system.

According to another object of the present invention, a personal subscriber station (PSS: hereinafter referred to as 'PSS') in a sleep mode is a radio access station (RAS: RAS). In the system for operating the smart antenna in the sleep mode of the personal subscriber station in the portable Internet system when performing 'Periodic Ranging' and 'Periodic Ranging', ranging code (Ranging Code) and Receives a ranging request message including a training sequence, calculates a weight vector for beamforming using the received distortion degree of the training sequence, and uses the calculated weight to calculate the weight vector. Smart in the sleep mode of the personal subscriber station in the mobile Internet system, characterized in that it comprises a RAS for determining the beam pattern of the antenna It provides a system for the operation of the antenna.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

5 is a block diagram schematically illustrating a system for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system according to an exemplary embodiment of the present invention.

As shown in FIG. 5, a system for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system according to a preferred embodiment of the present invention is a personal subscriber station (PSS). 500, a radio access station (RAS: RAS) 510, an access control router 520, which is an access control router for accommodating a plurality of RASs 510, Home Agent (HA: Home Agent, hereinafter referred to as 'HA') 530, Authentication Server (AAA Server: Authentication, Authorization, Accounting Server, hereinafter referred to as 'AAA Server') 540, IP Network 550, and Internet 560 and the like.

Here, the PSS 500 according to a preferred embodiment of the present invention refers to a mobile communication terminal using a high-speed wireless Internet service by accessing a portable Internet system according to a preferred embodiment of the present invention. The low power radio frequency (IF) / IF ( Intermediate Frequency (MAC) module and controller function, MAC (Media Access Control) frame variable control function, handoff function, authentication and encryption function according to service characteristics and propagation environment.

In particular, the PSS 500 according to the preferred embodiment of the present invention transmits a ranging request message including a ranging code and a training code in a sleep-mode RAS 510. Send periodically. Here, the training sequence is a known pattern already known between the RAS 510 and the PSS 500. The training sequence is transmitted to the RAS 510 after being attached to the ranging code so that the weight for beam forming of the smart antenna ( Weight Vector).

The RAS 510 according to the preferred embodiment of the present invention transmits data received from the ACR 520 to the PSS 500 by wireless, low power RF / IF module and controller function, OFDMA / TDD packet scheduling and channel multiplexing. MAC frame variable control function, 50 Mbps high-speed traffic real-time control function, handoff function, etc. according to function, service characteristics and propagation environment.

When the RAS 510 receives the ranging request message including the ranging code and the training sequence from the PSS 500, the RAS 510 weights the beamforming using the distortion degree of the received training sequence. Calculate Then, the beam pattern of the smart antenna is determined using the calculated weight.

Here, the RAS 510 estimates the channel state using the distortion degree of the training sequence, and calculates a weight using the gain and phase information of the channel obtained as a result of the prediction. Here the channel has a reversible characteristic.

In addition, the beam pattern formed in the RAS 510 according to the preferred embodiment of the present invention uses a Sample Matrix Inversion (SMI) method, a Least Mean Square (LMS) method, or a Recursive Least Square (RLS) method. The beam pattern formed in the RAS 510 is determined by continuously updating weights according to repetitive transmission of the training sequence.

Meanwhile, the PSS 500 and the RAS 510 according to the present invention have a 50 Mbps packet transmission modulation and demodulation function, a high speed packet channel coding function, a real time modem control function, and the like for data transmission.

ACR 520 according to a preferred embodiment of the present invention is an access control router that accommodates a plurality of RAS (510) handoff control function between the RAS 510, handoff function between the ACR 520, packet routing function, the Internet It has a connection function and the like, and is connected to the IP network 550.

The HA 530 according to the preferred embodiment of the present invention performs routing for transmitting a packet from an external packet data service server such as the Internet 560, and the AAA 540 interworks with the RAS 510 to perform PSS. Charging for the packet data used at 500 is performed, and the connection from the PSS 500 is authenticated.

The IP network 550 according to the preferred embodiment of the present invention connects the RAS 510, the ACR 520, the HA 530, the AAA 540, and the like, and receives an external packet data service such as the Internet 560. The packet data is received and transmitted to the RAS 510.

6 is a view schematically showing a periodic ranging procedure according to a preferred embodiment of the present invention.

During listening-interval, the PSS 500 scans the uplink map UL-MAP to find a periodic ranging region (S600). The PSS 500 selects a random subchannel, a symbol, and a code to determine whether there is data to be transmitted (S602) and transmits a ranging request code (S604). At this time, the training sequence according to the preferred embodiment of the present invention is transmitted together, Figure 7 shows an example of the ranging request message including the training sequence.

After a predetermined time in the PSS 500, the ranging request is randomly repeated with an exponent of 2 (S606), a random subchannel, a symbol, a code, etc. are selected (S608), and the ranging request code is repeatedly transmitted ( S610). When the PSS 500 receives a response message indicating that there is no data to be transmitted (S612), the time, power, and frequency are adjusted (S614), and a random subchannel, symbol, code, and the like are selected (S616). It transmits (S618). Again, the training sequence is also sent.

On the other hand, when receiving a response message that there is data to be transmitted from the PSS 500 (S620), after adjusting the time, power, frequency PSS 500 is in the awake mode (S622).

8 is a flowchart schematically illustrating a process for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system according to an exemplary embodiment of the present invention.

First, the PSS 500 according to a preferred embodiment of the present invention scans an uplink map to find a periodic ranging region (S800). When the ranging period is reached after scanning, the PSS 500 transmits a ranging request message including a ranging code and a training sequence to the RAS 510 (S802).

Upon receiving the ranging request message, the RAS 510 calculates a weight for beamforming using the distortion degree of the training sequence (S804). That is, the channel state is estimated using the distortion degree of the training sequence, and the weight is calculated using the gain and phase information of the channel obtained as a result of the prediction.

The RAS 510 determines the beam pattern of the smart antenna by using the calculated weight (S806), wherein the beam pattern is formed by a sample matrix inversion (SMI) method, a least mean square (LMS) method, or a recursive least square (RLS). ), And the beam pattern formed in the RAS 510 is determined by continuously updating the weight according to the repeated transmission of the training sequence.                     

The above description is merely illustrative of the present invention, and those skilled in the art to which the present invention pertains may various modifications without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed herein are not intended to limit the present invention but to describe the present invention, and the spirit and scope of the present invention are not limited by these embodiments. It is intended that the scope of the invention be interpreted by the following claims, and that all descriptions within the scope equivalent thereto shall be construed as being included in the scope of the present invention.

As described above, according to the present invention, the ranging request message is transmitted by including the training sequence information known in advance between the personal subscriber station and the RAS, thereby determining the beam pattern when applying the adaptive array antenna method, which is a kind of smart antenna method. In this case, it is possible to provide optimal beamforming to the user by using real-time signal processing technology according to the user's position even in the sleep mode of the terminal.

Claims (11)

A Personal Subscriber Station (PSS), which is in a Sleep Mode state, is referred to as a Radio Access Station (RAS) and Periodic Ranging (Periodic). A method for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system when performing a ranging), (a) receiving a ranging request message including a ranging code and a training sequence from the PSS; (b) calculating a weight vector for beamforming using the distortion degree of the training sequence; And (c) determining the beam pattern of the smart antenna using the weights Method for operating the smart antenna in the sleep mode of the personal subscriber station in the portable Internet system comprising a. The method of claim 1, In step (b), It is characterized by estimating the channel state using the distortion degree of the training sequence, and calculating the weight using the gain and phase information of the channel obtained as a result of the prediction. Method for operating smart antenna in sleep mode of personal subscriber station in internet system. The method of claim 2, The channel has a reversible characteristic, characterized in that for the operation of the smart antenna in the sleep mode of the personal subscriber station in a portable Internet system. The method of claim 1, In step (c), The beam pattern may be formed using a Smart Matrix Inversion (SMI) method, a Least Mean Square (LMS) method, or a Recursive Least Square (RLS) method. Way for you. The method of claim 1, The beam pattern is determined by continuously updating the weight according to repetitive transmission of the training sequence. The method for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system. A Personal Subscriber Station (PSS), which is in a Sleep Mode state, is referred to as a Radio Access Station (RAS) and Periodic Ranging (Periodic). A system for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system when performing a ranging), Receive a ranging request message including a ranging code and a training sequence from the PSS and calculate a weight vector for beamforming using the distortion degree of the received training sequence. RAS for determining the beam pattern of the smart antenna using the calculated weights System for the operation of the smart antenna in the sleep mode of the personal subscriber station in a portable Internet system comprising a. The method of claim 6, PSS that transmits and receives data using a portable Internet service, and periodically transmits the ranging request message including the ranging code and the training sequence to the RAS in the sleep mode. System for operation of the smart antenna in the sleep mode of the personal subscriber station in the portable Internet system, characterized in that it further comprises. The method of claim 6, In the RAS, the channel state is estimated using the distortion degree of the training sequence, and the weight is calculated using gain and phase information of the channel obtained as a result of the prediction. A system for operating a smart antenna in a sleep mode of a personal subscriber station in a portable internet system. The method of claim 8, The channel is a system for operating a smart antenna in the sleep mode of the personal subscriber station in the portable Internet system, characterized in that the reversible characteristics. The method of claim 6, The beam pattern may be formed using a Smart Matrix Inversion (SMI) method, a Least Mean Square (LMS) method, or a Recursive Least Square (RLS) method. System. The method of claim 6, The beam pattern is determined by continuously updating the weights according to repetitive transmission of the training sequence.

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