KR20150080320A - Method and apparatus of providing mobile communication service on the sea - Google Patents

Abstract

There is provided a base station signal relay method and apparatus for providing a mobile communication service in the sea. A signal relay method according to an embodiment of the present invention includes a system information acquisition step of receiving system information from a base station, a preamble format information acquisition step of acquiring preamble format information included in the SIB2 of the system information, Estimating a distance r to the base station based on the preamble format information, and determining whether to amplify the signal based on the preamble format and the r.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for providing a mobile communication service at sea,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile communication service, and more particularly, to a method and an apparatus for providing a mobile communication service in a maritime area.

As the use of wireless communication services is expanding, the target area of communication service is also gradually expanding. As maritime activities have increased, maritime has also become a target area for telecommunication services. The mobile communication service at sea is provided in the form of providing for marine vessels operating at sea. Conventionally, in a marine mobile communication service, marine vessels have a repeater, and receive signals from the base stations and relay signals to mobile communication terminals in the marine vessel.

It is difficult to apply the mobile communication service in the land because of the land and other service environment. The radio wave environment at sea, the number of terminals to be provided with service, and the requirement of relatively wide coverage are one of factors to be considered in providing mobile communication services at sea.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a signal relay method and apparatus capable of providing an efficient mobile communication service at sea.

Another object of the present invention is to provide a method and an apparatus for providing a mobile communication service in the marine environment, which can reduce PCI pollution by selecting a Physical Random Access Channel (PRACH) adaptively according to a service area .

In one aspect of the present invention, a base station signal relay method for providing a mobile communication service in the sea according to an embodiment of the present invention includes a system information acquisition step of receiving system information from a base station, Acquiring preamble format information included in the preamble format information; calculating a distance r to the base station based on the preamble format information; And determining whether to amplify the signal.

The signal amplification decision step may include determining that the signal is amplified when the preamble format is 1 and the r is 15 Km or more, and relaying the amplified signal.

The calculation of r can be made based on the timing advance value.

The estimation of r can be determined by the following equation.

Where c is the speed of light, Ta is the timing advance value and is an integer value between 0 and 1282, and Ts is the default time unit of the LTE air interface defined in 3GPP 36.211.

The step of determining whether to amplify the signal may include a step of amplifying the most significant signal regardless of the format of the preamble and repeating the step if r is less than 15 Km.

In another aspect of the present invention, a wireless device in accordance with an embodiment of the present invention includes a processor that is operatively coupled to an RF unit and an RF unit for receiving a signal from a base station and for transmitting an amplified signal, Acquires preamble format information included in SIB2 of the system information, calculates a distance r from the base station to the base station based on the preamble format information, and determines whether to amplify the signal of the base station based on r.

The processor may be configured to determine that the signal is amplified when the preamble format is 1 and the r is 15 Km or more and relay the amplified signal.

The processor may estimate r based on a timing advance value.

The wireless device may be a modem provided on the ship for managing and checking a repeater installed in a ship and receiving a signal from a land base station and relaying the signal to a wireless terminal of the ship.

In the provision of mobile communication service in the sea, it is possible to adaptively determine the base station signals to be relayed on the ship operating on the sea, thereby reducing the power consumption and increasing the recyclability of the radio resources, Can be utilized. The transmission of arbitrary access channels with a preamble format that supports wide coverage can be optimized to reduce PCI pollution at sea and reduce repeater implementation costs.

1 shows the interference phenomenon between a base station for maritime service and a base station for land-based service.
FIG. 2 is a graph showing the influence of reflected waves, and FIG. 3 is a graph showing a reception level according to a transmitted antenna height.
4 is a flowchart illustrating a procedure for determining whether a base station signal is relayed in a method for providing a mobile communication service in the sea according to an embodiment of the present invention.
5 is a flowchart showing a specific example of a method for providing mobile communication service at sea according to an embodiment of the present invention.

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In addition, numerals (e.g., first, second, etc.) used in the description of the present invention are merely an identifier for distinguishing one component from another.

Also, in this specification, when an element is referred to as being "connected" or "connected" with another element, the element may be directly connected or directly connected to the other element, It should be understood that, unless an opposite description is present, it may be connected or connected via another element in the middle.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate a thorough understanding of the present invention, the same reference numerals are used for the same means regardless of the number of the drawings.

Hereinafter, a fourth generation mobile communication service, LTE (Long Term Evolution) will be described as an example of an embodiment of the present invention as a mobile communication service provided at sea, but this is for convenience of description, . The technical idea of the present invention is also applicable to mobile communication services other than LTE services. When applied to other mobile communication systems, LTE related terms and names of the present specification are replaced with corresponding terms and names in the corresponding mobile communication system .

One element that determines the coverage, which is the service coverage in the LTE communication service, is the transmission range of PRACH (Physical Random Access CHannel) channel. PRACH is connected with RACH (Random Access CHannel) To the base station. That is, when the MS transmits a response to a message received from a paging channel (PCH) or transmits data requesting a traffic channel to the network, the PRACH can be used The transmission range of the PRACH is an element that determines the radius of a cell that can provide an LTE service.

Table 1 illustrates each parameter value according to the format of the PRACH.

Preamble Format Allocated Subframes T _SEQ
(T _S ) T _CP
(T _S ) T _CP
(㎲) T _GT
(T _S ) T _GT
(㎲) Max Delay Spread
(㎲) Max cell Radius
(km) 0 One 24576 3168 103.125 2976 96.875 5.208 14.531 One 2 24576 21024 684.375 15840 515.625 16.666 77.344 2 2 49152 6240 203.125 6048 196.875 5.208 29.531 3 3 49152 21024 684.375 21984 715.625 16.666 102.65 4 (TDD) Special Frame 4096 448 14.583 576 18.75 16.666 4.375

In the LTE system, the preamble of the PRACH can have five formats (0 to 4), and each has a different cell radius according to the preamble format. In Table 1, when the preamble format is 0, the cell radius is 14.53 km, and when the preamble format is 1, the cell radius is 77.344 Km. In other words, when the PRACH of the preamble format 0 is used, the radius of the cell where the LTE service is provided may be approximately 15 km, and the radius of the cell where the LTE service is provided when the PRACH of the preamble format 1 is used may be 77 km.

Most LTE base stations currently in operation support preamble format 0 to preamble format 3. Here, the base station must support preamble format 1 or preamble format 3 for an ocean service requiring wide coverage.

However, in order to support the preamble format 1 or 3, the base station must consume more system resources than other preamble formats. In addition, power consumption and reuse of radio resources are disadvantageous.

In order to efficiently utilize radio resources, it is necessary that the PRACH properly adjusts the preamble format according to the service environment. If the environment of the marine service is assumed, there is no obstacle at sea, so a lot of the physical cell ID (PCI) for land service is transmitted, which may cause PCI pollution.

The method of providing a mobile communication service according to an embodiment of the present invention can compensate for a coverage imbalance due to a difference in a PRACH preamble format that can occur in a maritime service. The maritime service can be a service on the ship. The service on the ship is characterized by the fact that the service is provided in a very limited area, and the possibility of interference with other areas is very low. Also, since the service should be provided at a distance far from the base station relative to the service on the land, a separate repeater for the maritime service can be used. The method for providing mobile communication service according to the embodiment of the present invention can provide a seamless maritime service by allowing the repeater for maritime service to have a function of determining PCI for maritime service and PCI for land service.

1 shows the interference phenomenon between a base station for maritime service and a base station for land-based service.

The base station for the maritime service is installed at a higher position than the base station for the land service, as shown in FIG. 1, in consideration of the coverage of a relatively large maritime service. Since the base station for maritime service is located at a relatively high position, it is possible to transmit to a remote terminal because there are few obstacles.

In the process of propagation of radio waves, seawater reflected waves are generated at sea level within the coverage. Due to the influence of the reflected wave, the terminal receiving the radio wave of the base station receives a signal with a non-uniform energy. That is, if the phase is the same according to the phase of the reflected wave, the signal received by the terminal becomes large, and when the phase is opposite, the intensity of the received signal decreases. It is generally the same phenomenon as the fading caused by an obstacle

FIG. 2 is a graph showing the influence of reflected waves, and FIG. 3 is a graph showing a reception level according to a transmitted antenna height.

The higher the antenna height (the height of the station where the base station is installed), the lower the loss, while the longer service is possible. On the other hand, the null point increases rapidly due to reflected waves. On the contrary, if the antenna height is low, it is difficult to perform long distance service due to loss, but the zero point occurring at a short distance is reduced.

When the terrestrial service signal and the maritime service signal are overlapped, the terminal may have trouble connecting to the base station. The UE performs the synchronization process using the base station signal. Therefore, if a signal having a preamble format of 0 is received at a distance of 15 km or more, it is impossible to synchronize with the base station that transmitted the preamble format 0 signal.

In general, a repeater for marine service uses a wireless repeater because it can not receive or transmit a signal through a wired network due to the characteristics of a service area. According to the embodiment of the present invention, the repeater can further perform a function of determining the preamble format of the received PRACH and determining whether the preamble is amplified, in addition to the relay / transmission function of the mobile communication signal.

The determination of the preamble format and the determination of whether or not to perform the preamble format may be performed by a module implemented in the repeater or by a separate communication device provided in the repeater. At this time, a separate communication device may be a modem provided in the repeater for checking and monitoring the status of the repeater. Hereinafter, the operation of the modem provided in the repeater will be described by way of example.

According to an embodiment of the present invention, the repeater can perform a service by amplifying only the preamble format 1 signal in an area of 15 km or more by determining the preamble format of the received PRACH.

4 is a flowchart illustrating a procedure for determining whether a base station signal is relayed in a method for providing a mobile communication service in the sea according to an embodiment of the present invention.

In step S20, the base station determines whether to relay the base station. The base station determines whether to relay the base station in step S30. In step S30, And determining whether to relay based on a preamble format and a distance between the estimated base station and the relay period (S40).

The repeater receives system information (SI) broadcasted by the base station (S10). System information consists of MIB (Master Information Block) and multiple SIB (System Information Block).

The SIB2 signal, which is one of the plurality of SIBs, is one of the information constituting the system information and includes radio resource setting information. The radio resource setting information included in the SIB2 signal includes uplink carrier frequency and uplink channel bandwidth, RACH setting, paging setting, uplink power control setting, PUCCH (Physical Uplink Control Channel) setting, and PUSCH (Physical Uplink Shared Channel) Lt; / RTI >

The RACH setup information in the SIB2 signal includes a powerRamping parameter indicating preamble information, transmission time information, initial transmission power, and a ramping step as information necessary for the UE to perform a random access (RA) procedure.

Table 2 is a correlation table between the PRACH setting and the preamble format.

PRACH
Configuration
Index Preamble
Format System
Frame
number Subframe
number PRACH
Configuration
Index Preamble
Format System
Frame
number Subframe
number 0 0 Even One 32 2 Even One One 0 Even 4 33 2 Even 4 2 0 Even 7 34 2 Even 7 3 0 Any One 35 2 Any One 4 0 Any 4 36 2 Any 4 5 0 Any 7 37 2 Any 7 6 0 Any 1, 6 38 2 Any 1, 6 7 0 Any 2, 7 39 2 Any 2, 7 8 0 Any 3, 8 40 2 Any 3, 8 9 0 Any 1, 4, 7 41 2 Any 1, 4, 7 10 0 Any 2, 5, 8 42 2 Any 2, 5, 8 11 0 Any 3, 6, 9 43 2 Any 3, 6, 9 12 0 Any 0, 2, 4, 6, 8 44 2 Any 0, 2, 4, 6, 8 13 0 Any 1, 3, 5, 7, 9 45 2 Any 1, 3, 5, 7, 9 14 0 Any 0,1,2,3,4,5,6,7,8,9 46 N / A N / A N / A 15 0 Even 9 47 2 Even 9 16 One Even One 48 3 Even One 17 One Even 4 49 3 Even 4 18 One Even 7 50 3 Even 7 19 One Any One 51 3 Any One 20 One Any 4 52 3 Any 4 21 One Any 7 53 3 Any 7 22 One Any 1, 6 54 3 Any 1, 6 23 One Any 2, 7 55 3 Any 2, 7 24 One Any 3, 8 56 3 Any 3, 8 25 One Any 1, 4, 7 57 3 Any 1, 4, 7 26 One Any 2, 5, 8 58 3 Any 2, 5, 8 27 One Any 3, 6, 9 59 3 Any 3, 6, 9 28 One Any 0, 2, 4, 6, 8 60 N / A N / A N / A 29 One Any 1, 3, 5, 7, 9 61 N / A N / A N / A 30 N / A N / A N / A 62 N / A N / A N / A 31 One Even 9 63 3 Even 9

The repeater acquires the preamble format included in the SIB2 of the system information (S20). For example, the repeater confirms the SIB2 signal and can confirm that the preamble format is 1 if the PRACH configuration value is 17 ~ 31. If the obtained preamble format is identified as 1, it can be determined that the base station broadcasting the system information including the SIB 2 has a coverage of 15 Km or more.

The repeater calculates the distance between the base station and the relaying period (S30).

In one embodiment of the present invention, a timing advance value used for synchronization between terminals can be used for calculating the distance between the base station and the relay period. The following equation 1 can be used to calculate the distance r using the timing advance value.

Where c is the speed of light, Ta is the timing advance value and is an integer value between 0 and 1282, and Ts is the default time unit of the LTE air interface and is defined in 3GPP 36.211.

The Ta value for 15 Km is 192. If the Ta value is 192 or more, it is determined that the distance between the base station and the relay station is 15 km or more, and the preamble format can be confirmed.

The repeater determines whether to relay based on the distance between the base station and the relay period (S40).

If the point where the repeater is located is within 15 km from the base station, there is no problem in call connection using the base station signal of preamble format 0. Therefore, it is possible to continue the PCI monitoring for the received individual base station signal without determining relaying have.

If the distance between the relay station and the base station is 15 km or more and the preamble format of the acquired PRACH is 1, that is, if the coverage of the corresponding base station is 15 Km or more, the signal of the corresponding base station is relayed.

5 is a flowchart showing a specific example of a method for providing mobile communication service at sea according to an embodiment of the present invention.

The repeater receives signals of all receivable base stations. And measures the PCI in the received base station signal to grasp the base station signal that can be received at the current position.

The distance between the relay station and the base station that transmits a signal having a specific PCI (signal of a specific base station) based on the timing advance is calculated. The example of FIG. 5 is based on the Ta value 192 corresponding to 15 km.

If the Ta value is smaller than 192, it means that the distance between the repeater and the base station transmitting the signal is within 15 km. In this case, the process returns to the step of monitoring the signal transmitted from the base station without distinguishing the preamble format. This is because the mobile communication service can be provided irrespective of the preamble format in the presence of the ship within 15 km, in other words, regardless of the coverage that the base station signal can have.

If the Ta value is greater than 192, it means that the distance between the repeater and the base station transmitting the signal exceeds 15 km, which means that service availability can be determined according to the preamble format of the signal transmitted from the base station. Therefore, the preamble format is discriminated by referring to the PRACH_config setting information.

If the land service cell is larger than 15 km, the terminal searches for a list of neighbor base stations measured by the terminal. Searches for the highest signal among the searched adjacent base stations, and generates a Primary Synchronization Signal (PSS) and a Secondary Synchronization Signal (SSS) for synchronization acquisition with the base station. And mixes the generated signal and the wirelessly received signal to acquire synchronization with the newly generated base station. The MS again analyzes the SIB2 message and determines whether the preamble format is 1 or not.

The above procedure is continued until a PCI with a preamble format of 1 is found. If a base station having a preamble format of 1 is identified through the above-described process, the repeater amplifies the signal and services the received signal.

6 shows an example of a relay apparatus in which a relay method according to an embodiment of the present invention can be implemented.

Referring to FIG. 6, a conventional relay apparatus includes a wireless device 110 and an RF coupling 120. When the base station signal received through the antenna of the repeater is input through RF coupling, the wireless device 110 performs synchronization extraction, PCI confirmation, preamble format determination, amplification signal determination, and the like RF coupling 120 to the repeater. In another example embodiment, the wireless device 110 may be configured with an RF unit and a processor, and the RF unit may be configured to receive / transmit signals and the processor to perform the relaying method described above.

Meanwhile, the method for providing a mobile communication service in the sea according to an embodiment of the present invention may be implemented in a form of a program command that can be executed through a variety of means for processing information electronically and recorded in a storage medium. The storage medium may include program instructions, data files, data structures, and the like, alone or in combination.

Program instructions to be recorded on the storage medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of software. Examples of storage media include magnetic media such as hard disks, floppy disks and magnetic tape, optical media such as CD-ROMs and DVDs, magneto-optical media such as floptical disks, magneto-optical media and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. The above-mentioned medium may also be a transmission medium such as a light or metal wire, wave guide, etc., including a carrier wave for transmitting a signal designating a program command, a data structure and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as devices for processing information electronically using an interpreter or the like, for example, a high-level language code that can be executed by a computer.

The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

The above-described embodiments include examples of various aspects. While it is not possible to describe every possible combination for expressing various aspects, one of ordinary skill in the art will recognize that other combinations are possible. Accordingly, it is intended that the invention include all alternatives, modifications and variations that fall within the scope of the following claims.

Claims (12)

A method of relaying a base station signal for providing a mobile communication service in a marine environment,
A system information acquiring step of receiving system information from a base station;
A preamble format information acquiring step of acquiring preamble format information included in SIB2 of the system information;
Calculating a distance r to the base station based on the preamble format information; And
Determining whether to amplify a signal of the base station based on the preamble format and the r.
2. The method of claim 1,
Determining that the signal is amplified when the preamble format is 1 and the r is 15 Km or more, and relaying the amplified signal.
The method according to claim 1,
Wherein said calculating of r is based on a timing advance value.
The method of claim 3,
Wherein the estimation of r is determined by the following equation.

Where c is the speed of light, Ta is the timing advance value, an integer value between 0 and 1282, and Ts is the default time unit of the LTE air interface defined in 3GPP 36.211.
2. The method of claim 1,
And if the r is less than 15 Km, amplifying the strongest signal regardless of the format of the preamble and relaying the signal.
An RF unit for receiving a signal of the base station and transmitting the amplified signal; And
And a processor operatively coupled to the RF unit,
The processor comprising:
Receives system information (System Information) from the base station,
Acquires preamble format information included in SIB2 of the system information,
Calculating a distance r to the base station based on the preamble format information, and
And to determine whether to amplify a signal of the base station based on the preamble format and the r.
The method according to claim 6,
Wherein the processor is configured to determine to amplify the signal when the preamble format is 1 and the r is 15 km or more, and relay the amplified signal.
The method according to claim 6,
Wherein the processor estimates the r based on a timing advance value.
9. The method of claim 8,
Wherein the processor estimates the r by: < EMI ID = 17.1 >

Where c is the speed of light, Ta is the timing advance value, an integer value between 0 and 1282, and Ts is the default time unit of the LTE air interface defined in 3GPP 36.211.
7. The apparatus of claim 6, wherein the processor
And to amplify and relay the strongest signal irrespective of the format of the preamble if r is less than 15 Km.
The method according to claim 6,
Wherein the wireless device is a repeater installed on a ship and receiving signals from a land base station and relaying the signals to the ship's wireless terminal.
The method according to claim 6,
Wherein the wireless device is a modem installed in the ship for managing and checking a repeater installed in the ship for relaying the signal to a ship's wireless terminal by receiving a signal from a land base station.

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