KR101500305B1 - Radio resource allocation system and method for suppressing interference - Google Patents

Abstract

In the TD-SCDMA communication system, when a time slot having a large interference influence and a time slot having a large interference influence are allocated to a mobile terminal in a high-speed packet access service, a transmission rate is set to the lowest And more particularly, to a system and method for allocating radio resources for interference suppression, in which the transmission rate is gradually increased so as to reduce the influence of excessive interference.

A radio resource allocation system according to the present invention comprises: a mobile terminal located in an area of a base station and transmitting terminal information including transmission power to the base station; And a cross slot in which a cross slot is generated for a time slot to be allocated to the mobile terminal and a normal slot in which a cross slot is generated, And allocating one of the cross slots when the base station is smaller than the reference base station and setting an initial transmission rate lower for the allocated cross slot.

According to the present invention, radio resource can be efficiently allocated by suppressing cross slot interference. Therefore, the influence of the interference of the signal is greatly reduced, and thus the transmission efficiency of the TD-SCDMA communication system can be increased.

 TDD, CDMA, RNC, radio resource, allocation, time slot, base station, cross slot, Nomal slot, subframe, Switching Point

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a system and a method for allocating radio resources for interference suppression,

The present invention relates to a radio resource allocation system and method for interference suppression and, more particularly, to a radio resource allocation system and method for interference suppression in a fast packet access service in a time division synchronous code division multiple access (TD-SCDMA) If a mobile terminal is allocated to a timeslot having a large interference influence after distinguishing a time slot having a large influence and a time slot having a large influence, the transmission rate is set to be the lowest and the transmission rate is gradually increased to thereby reduce the influence of excessive interference And to a radio resource allocation system and method for suppressing interference.

In general, a High-Speed Downlink Packet Access (HSDPA) provides a high-speed transmission rate for downlink and can be utilized for various services such as file downloading, Internet search, remote server access, have. HSDPA Frequency Division Duplexing (FDD) based on WCDMA has been studied since 2000 and a stable system has been developed. However, HSDPA TDD (Time Division Duplexing) for TD-SCDMA has not been developed yet All.

Since TD-SCDMA is based on TDD and CDMA, time slots and channelization codes are allocated to provide services to each terminal. However, since data packets are not generated continuously during the service, it is necessary to temporarily release the allocated resources or to save radio resources using common radio resources.

In addition, because TD-SCDMA is a system based on CDMA, interference should be efficiently controlled. Particularly, in TD-SCDMA using time division duplex (TDD), downlink and uplink communication are performed using the same frequency. As a result, interference between the base station and the base station, between the base station and the terminal, .

1 is a diagram illustrating cross-slot interference in conventional TD-SCDMA.

In FIG. 1, it is assumed that switching points used in two neighboring cells do not coincide with each other. The transmission direction of TS3 and TS4 is opposite in both cells. When a terminal in the upper cell transmits data in TS3 in the uplink, the upper base station receives this information and acts as a large interference to the lower terminal. This is because the lower terminal in the same slot position is receiving data in the downlink. Likewise, if the lower base station transmits data from TS3 to the terminal, this signal will also interfere with the upper base station as well as the terminal. In this way, the interference caused by the inconsistency of the time slot transmission direction in the TDD cell reel environment is called cross-slot interference.

Cross-slot interference can occur between neighboring frequencies or carriers using the same frequency. In TD-SCDMA, the method of reducing cross-slot interference is to match the transmission direction of the time slot at all base stations. However, maintaining the same switching point at all base stations reduces network operational flexibility.

As a result, in TD-SCDMA system in which transmission and reception are simultaneously performed in the same frequency band, the boundary between the uplink and the downlink is set differently for each cell in order to ensure the operational flexibility of the system. . Since interference can have a significant impact on the performance of a CDMA system, such cross-slot interference can significantly degrade the performance of TD-SCDMA. Therefore, there is a need for an efficient radio resource allocation method capable of reducing cross-slot interference.

DISCLOSURE OF THE INVENTION The present invention for solving the above-mentioned problems is to provide a TD-SCDMA communication system in which a time slot having a large influence of interference and a time slot having a large influence of interference are distinguished from each other, The present invention provides a radio resource allocation system and a radio resource allocation method for interference suppression that reduce the influence of excessive interference by setting a transmission rate to the lowest and gradually increasing the transmission rate.

According to an aspect of the present invention, there is provided a radio resource allocation system comprising: a mobile station located in an area of a base station and transmitting terminal information including transmission power to the base station; And a cross slot in which a cross slot is generated for a time slot to be allocated to the mobile terminal and a normal slot in which a cross slot is generated, And allocating one of the cross slots when the base station is smaller than the reference base station and setting an initial transmission rate lower for the allocated cross slot.

In addition, the base station controller allocates one of the normal slots when the mobile station is located at a boundary of the base station cell and the transmission power is greater than a reference.

Also, the base station controller allocates one of the cross slots when the mobile terminal is located at a boundary of the base station cell and the transmission power is greater than a reference but the normal slot to be allocated does not exist.

In addition, the base station controller sets an initial transmission rate lower for the cross slot allocated to the mobile terminal.

Then, the BS controller increases the transmission rate by a maximum transmission rate up to the maximum transmission rate when the influence of the interference is below the reference value after allocating the cross slot to the MS.

According to another aspect of the present invention, there is provided a base station controller for allocating radio resources to a mobile station located in an area of a base station, the base station controller including: a communication unit for communicating with the mobile station via the base station; ; A resource allocator for allocating one of the cross slots when the transmission power of the mobile terminal is smaller than a reference by dividing a time slot to be allocated to the mobile terminal into a cross slot and a normal slot; A resource allocation database storing information on radio resources allocated to the mobile terminal and radio resources not allocated to the mobile terminal; A data processor for processing data or signals to be transmitted to the mobile terminal; And a controller for controlling the radio resources to be allocated to the mobile terminal.

The resource allocation unit allocates one of the normal slots when the mobile station is located at a boundary of the base station cell and the transmission power of the mobile station is greater than a reference.

Also, the resource allocation unit allocates one of the cross slots when the normal power of the mobile station is greater than the reference but the normal slot to be allocated does not exist.

In addition, the controller sets the initial transmission rate to a lower value for the cross slot allocated to the mobile terminal.

The controller may increase the transmission rate to a maximum transmission rate step by step after the cross slot is allocated to the mobile terminal when the influence of the interference is below the reference value.

According to another aspect of the present invention, there is provided a method of allocating radio resources to a mobile station located in an area of a base station, the method comprising the steps of: (a) Receiving terminal information including transmission power from the mobile terminal; (b) dividing a time slot to be allocated to the mobile terminal into a cross slot and a normal slot; (c) allocating the cross slot or the normal slot according to the transmission power of the mobile terminal; And (d) setting an initial transmission rate to be low when allocating the cross slot to the mobile terminal.

In the step (c), one of the cross slots is allocated when the mobile terminal is located close to the base station and the transmission power is smaller than a reference.

In the step (c), one of the normal slots is allocated when the mobile terminal is located at a boundary of the base station cell and the transmission power is greater than a reference.

In the step (c), if the transmission power of the mobile terminal is larger than the reference value, one of the cross slots is assigned when the normal slot to be allocated does not exist.

In the step (d), if the interference effect is less than the reference value after the cross slot is allocated to the mobile terminal, the transmission rate is gradually increased to the maximum transmission rate.

(A) receiving terminal information including a transmission power from a mobile terminal; (b) dividing a time slot to be allocated to a mobile terminal into a cross slot and a normal slot; (c) assigning a cross slot or a normal slot according to the transmission power of the mobile terminal; And (d) setting an initial transmission rate lower when a cross slot is allocated to the mobile terminal.

In the step (c), when the mobile terminal is located close to the base station and the transmission power is smaller than the reference, the step (c) may record the program on the recording medium with a program for assigning one of the cross slots.

In the step (c), when the mobile station is located at the boundary of the base station cell and the transmission power is larger than the reference, the program may be recorded in the recording medium with a program for allocating one of the normal slots.

In the step (c), when the transmission power of the mobile terminal is larger than the reference, if there is no normal slot to be allocated, one of the cross slots may be recorded in the recording medium.

The step (d) may be performed by recording a program on the recording medium by increasing the transmission rate to a maximum transmission rate in a case where the influence of the interference is below the reference value after assigning the cross slot to the mobile terminal.

According to the present invention, radio resource can be efficiently allocated by suppressing cross slot interference. Therefore, the influence of the interference of the signal is greatly reduced, and thus the transmission efficiency of the TD-SCDMA communication system can be increased. Since appropriate radio resources can be allocated according to the transmission power of each terminal, data can be transmitted securely without deteriorating the performance of the system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the TD-SCDMA communication system is one of the third generation (3G) mobile communication technologies combining the advantages of TDD (Time Division Duplexing) / TDMA (Time Division Multiple Access) and CDMA. The TD-SCDMA system was proposed by the China Wireless Technology Standard (CWTS) Group in 1998 based on the enormous potential of the Chinese mobile communications market. In March 2000, the 3GPP (The Third Generation Partnership Project), which is responsible for the standardization of the 3G mobile communication system, was established as the 3G standard by ITU (International Telecommunications Union) And is now registered as a formal standard.

TD-SCDMA technology combines TDD and TDMA technology with Synchronous CDMA technology. Thus, it has distinct advantages over other 3G technologies such as Wideband Code Division Multiple Access (WCDMA) and CDMA 2000, such as flexible frequency allocation, low cost transceiver implementation and simple network evolution from GSM systems.

It can be considered that TD-SCDMA technology is replaced by the TD-SCDMA scheme instead of the WCDMA scheme, rather than a completely different system from the existing WCDMA. In 3GPP, which actually creates standard specifications of WCDMA and TD-SCDMA, the remainder is treated the same as WCDMA except for the physical layer and the second layer of the air interface. Therefore, the basic structure of the TD-SCDMA is the same as the structure of the WCDMA system.

The most basic operating mode adopted in TD-SCDMA technology is TDD. That is, the service is provided using the same band without separating the frequencies for the uplink and the downlink. The gain obtained by using the TDD scheme is as follows.

Since the uplink and downlink are not separated, a guard band for frequency separation is not required, and asymmetric services can be supported in both directions, thereby maximizing frequency efficiency.

The TDD-SCDMA can use one RF module for transmission and reception, and it is possible to realize a low-cost transceiver. Since the propagation characteristics of channels for downlink and uplink are very similar, system capacity can be improved by utilizing Smart Antenna technology and Joint Detection technology.

2 is a block diagram schematically illustrating a configuration of a TD-SCDMA communication system to which a radio resource allocation method for interference suppression according to an embodiment of the present invention is applied.

2, a TD-SCDMA communication system 200 according to the present invention includes mobile stations (MSs) 210 to 214, Node Bs 220 to 224, a Radio Network (RNC) 230, 232, a Serving GPRS Support Node (SGSN) 240, a Gateway GPRS Support Node (GGSN) 250, And a Home Location Register (HLR) 260.

The mobile terminals 210 to 214 transmit and receive voice signals through the base stations 220 to 224 and transmit the voice signals to the base stations 220 to 224, the RNCs 230 and 232, the SGSN 240 and the GGSN 250, The packet data can be received from the Internet network.

Also, the mobile terminals 210 to 214 receive only the codes allocated to themselves through the base stations 220 to 224, and recover the data. That is, when the mobile terminals 210 to 214 check whether the data to be received exists through the HS-SCCH, the mobile terminals 210 to 214 receive the data through the HS-PDSCH (High-Speed Physical Downlink Shared Channel) . If the recovery of the received data is successful, ACK information is transmitted through the HS-SICH. Otherwise, NAK information is transmitted to notify the data transmission failure.

In addition, the mobile terminals 210 to 214 convert the quality of the downlink channel into a CQI value (0 to 30) and transmit the CQI value to the base stations 220 to 224 via a High-Speed Shared Information Channel (HS-SICH).

When the mobile terminal 210-214 does not start the service related to the data transmission even after a certain time after the time slot and the channel code are allocated from the base stations 220-224, Time is counted by the timer, and the set radio resources are returned to the base stations 220 to 224 every predetermined time.

At this time, the mobile terminals 210 to 214 use a transmission rate lower than the transmission rate requested by the released service for the returned radio resources as a reference, and reserve the minimum radio resources without releasing all the allocated resources Resources.

The base stations 220 to 224 transmit voice signals or data related to mobile communication to the mobile terminal 110 as radio signals. At this time, the base stations 220 to 224 may be referred to as " Node-B " and also referred to as "UTRAN (Universal Mobile Telecommunication System) Terrestrial Radio Access Network ".

In addition, the base stations 220 to 224 select a terminal to transmit data in the next transmission period (TTI), determine the number of channel codes to use, a modulation method, a channel coding rate, and the like, To the corresponding terminal.

The base stations 220 to 224 divide a time slot in which a cross-slot occurs in a sub-frame and a time slot in which a cross-slot occurs in the sub-frame for the mobile terminals 210 to 214, One of the normal slots is allocated to a terminal located at a boundary between the base station and the base station, and one of the cross-slots is allocated to the terminal located close to the base station because the transmission power is small. The initial transmission rate is set low for one terminal.

The RNCs 230 and 232 manage a plurality of base stations 220 to 224 and control transmission and reception of voice signals and data through a plurality of base stations 220 to 224. Also, the RNCs 230 and 232 perform radio interval matching with the mobile terminals 210 to 214 and matching with the SGSN 240.

The RNCs 230 and 232 perform functions such as allocation, reassignment, and release of radio resources to a plurality of mobile terminals 210 to 214 in a region managed by a plurality of base stations 220 to 224.

The SGSN 240 manages the movement of the mobile terminals 210 to 214. To this end, the SGSN 240 includes a Visitor Location Register (VLR) that stores location information of the mobile terminals 210 to 214.

The GGSN 250 manages a PDP address requested by the mobile terminals 210 to 214.

The HLR 260 is a database storing service profiles related to subscriber information of the mobile terminals 210 to 214. The HLR 260 includes a mobile identification number (MIN) number of the mobile terminals 210 to 214, , An electronic serial number (ESN), and a service type. The HLR 260 functions to store subscriber information including information on the base stations 220 to 224 and the RNCs 230 and 232 where the mobile terminals 210 to 214 are located.

The mobile terminals 210 to 214 transmit an Activate PDP Context Request message to the base stations 220 to 224 and the RNCs 230 to 224 when the mobile terminals 210 to 214 are located in the coverage area of the base stations 220 to 224. [ 232 to the SGSN 240. [ Accordingly, the SGSN 240 transmits a Create PDP Context Request message to the GGSN 250 based on the received PDP context.

The GGSN 250 receives packet data from the Internet and provides packet data to the mobile terminals 110 to 114 via the SGSN 240, the RNCs 230 and 232 and the base stations 220 to 224.

When the SGSN 240 receives an active PDP context request message from the mobile terminals 110 to 114, the SGSN 240 transmits an RAB assignment request message to the RNC 130, (RAB) assignment message from the RNC 130 after assigning a radio access bearer (RAB) to the mobile terminals 110 to 114.

The RNCs 230 and 232 transmit a radio link resource (RLR) Prepare message to the base stations 220-224 and inform the base stations 220-224 that the radio link resource (RLR) Message.

The RNCs 230 and 232 transmit a message for committing a radio link resource RLR to the base stations 220 through 224 and then transmit a message to the mobile terminals 210 through 224 via the base stations 220 through 224. [ 214 to receive a Setup Complete message of the RAB from the mobile terminals 210-214.

3 is a diagram illustrating a structure of a transmission frame in a TD-SCDMA communication system according to an embodiment of the present invention.

Referring to FIG. 3, a transmission frame in a TD-SCDMA communication system to which the present invention is applied has a length of 10 ms which is the same as 3GPP WCDMA. A super frame is composed of several frames, and each frame is composed of two sub-frames having a length of 5 ms. In particular, the basic unit for data transmission in TD-SCDMA is a sub-frame.

In a sub-frame, a downlink signal and an uplink signal coexist, and a point in time when a direction of transmission is changed is called a switching point. In TD-SCDMA, as shown in FIG. 3, there are always two switching points within one sub-frame. Of the seven time slots (TS), TS0 is always allocated in the downlink and TS1 is always allocated in the uplink. Since the data transfer direction of TS0 and TS1 is different, this point also becomes a switching point. The remaining time slots can freely adjust the length allocated to up / down to support asymmetric traffic.

In FIG. 3, a total of four time slots are allocated to the downlink and three times slots are allocated to the uplink. Since the direction of the link is switched between TS3 and TS4, this channel becomes another switching point. In the sub-frame, a special signal supporting the operation of the TDD system is added in addition to the seven time slots. This information is defined between TS0 and TS1, and each of DwPTS (Downlink Pilot TS), UpPTS (Uplink Pilot TS) , And a guard period (GP). The DwPTS is a signal for transmitting pilot information for downlink, and is used for downlink synchronization and initial cell search.

UpPTS is composed of 160 chips, 32 chips are GP, and the remaining 128 chips are used as SYNC. This SYNC signal is also used for the initial synchronization and random access procedure of the uplink and for the measurement of the adjacent cell in handover. GP is a guard period that prevents overlap between DwPTS and UpPTS signals and consists of 96 chips.

4 is a diagram illustrating an example of radio resource allocation in a TD-SCDMA communication system according to an embodiment of the present invention.

As shown in FIG. 4, in the TD-SCDMA, the number of channelization codes usable in each time slot is limited to a maximum of 16, thereby reducing a multiple access interference (MAI) . In addition, various spreading factors (SF) and multicodes are supported to support high data rates.

Accordingly, the spreading factors usable in the TD-SCDMA are SF1, SF2, SF4, SF8, and SF16, and the mobile terminals 210 to 214 can simultaneously receive one or more codes. In particular, only the SF16 code is used for the downlink. FIG. 3 shows an example of radio resource allocation for downlink in TD-SCDMA. Since SF16 codes are used in each time slot, a total of 16 channelization codes can be used, and the basic resource allocation unit becomes one code.

Various services supported in TD-SCDMA are subjected to proper time slot and proper channelization codes. The basic radio resources of the TD-SCDMA physical layer can be discretized into a Resource Unit (RU), which considers one SF16 code as a basic allocation unit. For example, if one service uses two SF16 channelization codes, this service requires 2RU of radio resources. In addition, the total RU for each link is determined according to the number of time slots allocated for downlink and uplink. For example, if the first two of the six time slots except for the first time slot are allocated to the uplink and the remaining four to the downlink, a total of 32 RUs for the uplink and a total of 64 RU for the downlink Can be regarded as being allocated. For example, SF1 corresponds to 16 RUs and SF4 corresponds to 4 RUs.

Since TD-SCDMA can utilize the advantages of TDMA and CDMA, allocatable physical resources are composed of three resource combinations: carrier frequency, time slot, and channelization code. In addition, since it can divide physical resources spatially by use of Adaptive Array, which is one of Smart Antenna technologies, it can support dynamic channel allocation, reallocation and cancellation using four types of radio resources. However, the actual TD-SCDMA system is not allocating / reallocating / releasing resources in every sub-frame or slot, but allocating / reallocating / releasing radio resources for a longer time. Therefore, in the TD-SCDMA, the radio resource allocation is implemented in the base station controller (RNC) 130, not in the base station.

TD-SCDMA defines the number of time slots and the number of codes to be allocated to various services.

Table 1 below shows allocation criteria of time slot and channelization codes for various mobile communication services.

service
Kinds Transmission speed Downlink Uplink cordage TS  Number RU cordage TS  Number RU Voice call 12.2 kbps SF16  x 2 One TS 2 RU SF8  x 1 One TS 2 RU Modem / Fax 28.8 kbps SF16  x 3 One TS 3 RU SF4  x 1 One TS 4 RU 57.6 kbps SF16  x 6 One TS 6 RU SF2  x 1 One TS 8 RU Video phone 64 kbps SF16  x 8 One TS 8 RU SF2  x 1 One TS 8 RU data 64 kbps SF16  x 8 One TS 8 RU SF2  x 1 One TS 8 RU 128 kbps SF16  x 14 One TS 14 RU SF2  x 1 2 TS 16 RU 144 kbps SF16  x 8 2 TS 16 RU SF2  x 1 2 TS 16 RU 384 kbps SF16  x 10 4 TS 40 RU SF8  x 1
+ SF2  x 1 4 TS 40 RU

As shown in Table 1, at least 2 RU of resources are required for most services. It should be noted that the allocated time slots and channelization codes for each service are not changed except for service re-establishment. Therefore, in the case of the downlink 64 k bps service, 8 channelization codes are used. Even if the amount of data decreases or increases, the number of the channels is continuously occupied without using the proper number of codes.

5 is a block diagram schematically showing functional blocks of a base station controller according to an embodiment of the present invention.

5, a base station controller 130 according to the present invention includes a communication unit 510, a resource allocation unit 520, a resource allocation database (DB) 530, a data processing unit 540, and a control unit 550 .

The communication unit 510 communicates with the mobile terminals 210 to 214 via the base stations 120 to 126 or with the SGSN 240.

The resource allocation unit 520 allocates a time slot for the downlink and a time slot for the downlink to the mobile terminals 210 to 214 through the base stations 120 to 126 in order to allocate a dynamic physical channel to the mobile terminals 210 to 214. [ Allocate an episode.

In addition, the resource allocation unit 520 divides a time slot in which a cross-slot occurs in a sub-frame and a time slot in which a cross-slot occurs in the sub-frame for the mobile terminals 210 to 214, One of the normal slots is allocated to a terminal located at a boundary and a transmission power is high, and one of the cross-slots is assigned to a terminal located close to the base station because the transmission power is small. The initial transmission rate is set low for the terminal.

The resource allocation database 530 stores resources allocated to the mobile terminals 210 to 214 and resources not allocated thereto, that is, time slots and channelization codes allocated to the mobile terminals 210 to 214, And the channelization code are stored in the resource table as shown in FIG.

The data processing unit 540 processes voice signals and data to be transmitted to the mobile terminals 210 to 214 according to a processing method of a general mobile communication network.

The control unit 550 controls transmission / reception of voice signals and data, and allocation of radio resources to the mobile terminals 210 to 214.

6 is a block diagram schematically illustrating functional blocks of a mobile terminal according to an embodiment of the present invention.

6, the mobile terminals 210 to 214 to which the present invention is applied include a communication unit 610, an allocated resource analysis unit 620, a display unit 630, a storage unit 640, an adequacy checking unit 650, (660).

The communication unit 610 communicates with the base stations 220 to 224. Also, the communication unit 610 can communicate with the RNCs 230 and 232 via the base stations 220 to 224. [

The radio resource setting unit 620 transmits the allocated resource information to the mobile stations 210 to 214 for the resources allocated to the mobile terminals 110 to 124 by the RNCs 230 and 232 The base station receives the allocated resource information, and sets a time slot and a channelization code allocated to the base station.

The display unit 630 displays, for example, an operation state of the terminal.

The storage unit 640 stores the received packet data or stores data necessary for the operation of the terminal. In addition, the storage unit 640 stores information on the assigned time slot and the channelization code.

The adequacy checking unit 650 determines whether the received data is proper when the data is received using another radio resource, i.e., a time slot and a channelization code, from another terminal, and transmits the result to the controller 660. [

The control unit 660 controls the operation of the terminal and controls transmission / reception of data through the allocated time slot and channelization code. When it is determined that the data received by the adequacy checking unit 650 is not transmitted to the terminal, And discards the received data.

7 is a flowchart illustrating a radio resource allocation method according to an embodiment of the present invention.

Referring to FIG. 7, when the mobile stations 210 to 214 according to the present invention are located in an area managed by the base stations 220 to 224, the mobile terminals 210 to 214 transmit their terminal information to the RNCs 230 to 224 via the base stations 220 to 224, 232, and receives radio resources, i.e., time slots and channelization codes, from the RNCs 230 and 232.

At this time, the terminal information transmitted from the mobile terminals 210 to 214 also includes information on the transmission power, and the RNCs 230 and 232 transmit information on the transmission power of each terminal from the mobile terminals 210 to 214 Together.

FIG. 7 illustrates a time slot for an uplink and a downlink, which are used in a home cell in which the mobile terminals 210 to 214 are currently located, and a time slot for an uplink and a downlink used in a neighbor cell Along with time slots for.

However, in the subframe structure used in the home cell and the neighbor cell, the mobile terminals 210 to 214 use two times in the uplink in its own cell (home cell) Slot and a neighbor cell (neighbor cell) is allocated four time slots, cross-slot interference occurs in TS3 and TS4.

Since cross-slot interference has characteristics that only affect the corresponding timeslot, care must be taken when assigning radio resources to time slots that are cross-slotted. In order to reflect this, a method of allocating an appropriate time slot according to the transmission power of the terminal is used.

Accordingly, the RNCs 230 and 232 divide a cross slot in which a cross-slot occurs in a time slot in a sub-frame of the TD-SCDMA and a normal slot in which the cross slot occurs, in operation S702. At this time, a combination of time slots in which a cross-slot occurs is referred to as a cross slot, and a non-crossed slot is referred to as a normal slot.

In the cross-slot position, it is necessary to pay careful attention to resource allocation because it may have a large influence on the terminal or the base station of the neighboring cell even with a small transmission power.

Accordingly, the RNCs 230 and 232 determine whether the transmission power of each of the mobile terminals 210 to 214 is greater than the reference value based on the information on the transmission power of each terminal received from each of the mobile terminals 210 to 214 (S704).

In step S706, the RNCs 230 and 232 check whether there is a currently unallocated normal slot through the resource allocation unit 520 when the corresponding terminal is located at the cell boundary and the transmission power is large (S706).

If there is an unallocated normal slot through the resource allocation unit 520 (S708-YES), the RNCs 230 and 232 allocate one of the normal slots to the corresponding terminal located at the cell boundary and having a large transmission power (S710).

However, when the corresponding terminal is located close to the base stations 220 to 224 and the transmission power is smaller than the reference (S706-NO), even if the terminal is located at the cell boundary but there is no unallocated normal slot (NO in S708) The RNCs 230 and 232 allocate one of the cross slots to the corresponding terminal through the resource allocation unit 520 (S712).

At this time, the RNCs 230 and 232 set an initial transmission rate low for a terminal that allocates a cross slot in order to reduce the influence of the interference of the assigned cross slot (S714).

In the CDMA system, in order to increase the transmission rate, more channelization codes are allocated, so that the transmission power of the corresponding terminal increases and it is necessary to maintain the transmission rate as low as possible to lower the transmission power.

The RNCs 230 and 232 continuously monitor the influence of the interference to determine whether the interference effect is below the reference level (S716).

Therefore, if it is determined that the influence of the interference in the corresponding timeslot is not large (S716-YES), the RNCs 230 and 232 transmit the interference for the cross slot allocated to the corresponding terminal The transmission speed is increased stepwise (S718). 8 is a diagram illustrating a process of adjusting a transmission rate for cross slot interference mitigation according to an embodiment of the present invention. As shown in FIG. 8, the RNCs 230 and 232 set the initial transmission rate for the cross slot as 32 Kbps, and then 64 Kbps, 128 Kbps, and 384 Kbps, respectively, As shown in FIG.

At this time, the RNCs 230 and 232 can not increase the transmission rate infinitely and increase the maximum transmission rate required by the corresponding service to not exceed 384 Kbps.

If all of the normal slots that can be allocated to terminals having a large transmission power are exhausted as in step S708 and resources of a cross slot are allocated, the transmission rate is set to be low.

However, if the transmission power of the terminal is lower than a certain level, there is no restriction on the initial transmission rate.

On the other hand, a program for processing a radio resource allocation method of the base station controllers 230 and 232 for allocating radio resources to mobile terminals 210 to 214 located in an area covered by the base stations 220 to 224 is recorded on a recording medium . Here, the program may include: (a) receiving terminal information including a transmission power from the mobile terminal; (b) dividing a time slot to be allocated to a mobile terminal into a cross slot and a normal slot; (c) assigning a cross slot or a normal slot according to the transmission power of the mobile terminal; And (d) setting a low initial transmission rate when a cross slot is allocated to the mobile terminal.

Here, step (c) is a program for allocating one of the cross slots when the mobile terminal is located close to the base station and the transmission power is smaller than the reference.

The step (c) is a program for allocating one of the normal slots when the mobile terminal is located at the boundary of the base station cell and the transmission power is larger than the reference.

The step (c) is a program for allocating one of the cross slots when there is no normal slot to be allocated even if the transmission power of the mobile terminal is larger than the reference.

The step (d) is a program for gradually increasing the transmission rate up to the maximum transmission rate when the influence of the interference is below the reference, after assigning the cross slot to the mobile terminal.

As described above, according to the present invention, when a time slot having a large influence of interference and a time slot having a large influence of interference are distinguished in a high-speed packet access service of a TD-SCDMA communication system, It is possible to realize a radio resource allocation system and method for interference suppression, which makes it possible to reduce the influence of excessive interference by setting the lowest speed and gradually increasing the transmission rate.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents. Only. The scope of the present invention is defined by the appended claims rather than the detailed description and all changes or modifications derived from the meaning and scope of the claims and their equivalents are to be construed as being included within the scope of the present invention do.

The present invention can be applied to a mobile communication system that allocates dedicated radio resources for providing a data transmission service to a mobile terminal. The present invention is also applicable to a mobile communication system that allocates resources to mobile terminals located in a cell where cross slot interference occurs.

1 is a diagram illustrating cross-slot interference in conventional TD-SCDMA.

2 is a block diagram schematically illustrating a configuration of a TD-SCDMA communication system to which a radio resource allocation method according to an embodiment of the present invention is applied.

3 is a diagram illustrating a structure of a transmission frame in a TD-SCDMA communication system according to an embodiment of the present invention.

4 is a diagram illustrating an example of radio resource allocation in a TD-SCDMA communication system according to an embodiment of the present invention.

5 is a block diagram schematically showing functional blocks of a base station controller according to an embodiment of the present invention.

6 is a block diagram schematically illustrating functional blocks of a mobile terminal according to an embodiment of the present invention.

7 is a flowchart illustrating a radio resource allocation method according to an embodiment of the present invention.

8 is a diagram illustrating a process of adjusting a transmission rate for cross slot interference mitigation according to an embodiment of the present invention.

Description of the Related Art

200: TD-SCDMA communication system 210 to 214: mobile terminal

220 to 224: base station 230, 232: base station controller

240: SGSN 250: GGSN

HLR: 260 510:

520: resource allocation unit 530: resource allocation DB

540: Data processing unit 550:

610: communication unit 620: radio resource setting unit

630: Display section 640:

650: suitability checking unit 660:

Claims (20)

A mobile terminal located in an area of a base station and transmitting terminal information including transmission power to the base station; And A cross slot in which a cross slot is generated for a time slot to be allocated to the mobile terminal and a non-cross slot in which a cross slot is generated for the time slot to be allocated to the mobile terminal, Wherein the base station controller allocates one of the cross slots when the transmission power is smaller than a reference value and sets an initial transmission rate lower for the allocated cross slot; / RTI > Wherein the base station controller allocates one of the cross slots when the mobile terminal is located at a boundary of the base station cell and the transmission power is greater than a reference but there is no normal slot to allocate. Assignment system. delete delete The method according to claim 1, Wherein the base station controller sets an initial transmission rate lower for the cross slot allocated to the mobile terminal. The method according to claim 1, Wherein the base station controller increases the transmission rate step by step until a maximum transmission rate if interference effects are below a reference value after assigning the cross slot to the mobile terminal. A base station controller for allocating radio resources for a mobile terminal located in an area covered by a base station, A communication unit for communicating with the mobile terminal via the base station; A resource allocation unit for allocating one of the cross slots when a transmission power of the mobile station is smaller than a reference by dividing a time slot to be allocated to the mobile station into a cross slot and a normal slot; A resource allocation database storing information on radio resources allocated to the mobile terminal and radio resources not allocated to the mobile terminal; A data processor for processing data or signals to be transmitted to the mobile terminal; And A controller for controlling the radio resources to be allocated to the mobile terminal; / RTI > Wherein the resource allocator comprises: And allocates one of the cross slots when there is no normal slot to be allocated even if the transmission power of the mobile terminal is larger than a reference value. delete delete The method according to claim 6, Wherein the controller sets the initial transmission rate to a lower value for the cross slot allocated to the mobile terminal. The method according to claim 6, Wherein the controller increments the transmission rate by a maximum transmission rate up to a maximum transmission rate when the influence of the interference is below a reference value after allocating the cross slot to the mobile terminal. A radio resource allocation method of a base station controller allocating a radio resource to a mobile terminal located in an area covered by a base station, (a) receiving terminal information including transmission power from the mobile terminal; (b) dividing a time slot to be allocated to the mobile terminal into a cross slot and a normal slot; (c) allocating the cross slot or the normal slot according to the transmission power of the mobile terminal; And (d) setting an initial transmission rate to a lower value when the cross slot is allocated to the mobile terminal; / RTI > The step (c) And allocates one of the cross slots when the transmission power of the mobile terminal is greater than a reference but the normal slot to be allocated does not exist. 12. The method of claim 11, Wherein the step (c) allocates one of the cross slots when the mobile terminal is located close to the base station and the transmission power is smaller than a reference value. delete delete 12. The method of claim 11, Wherein the step (d) increases the transmission rate to a maximum transmission rate step by step when the influence of the interference is less than a reference value after allocating the cross slot to the mobile terminal. A computer-readable recording medium storing a program for executing the method according to any one of claims 11, 12 and 15. delete delete delete delete

Images