Abstract:
The disclosure is directed to a method of accessing a radio network, a server and a base station of a radio access network, and a non-transitory computer-readable storage medium thereof. In an embodiment, the method includes the following steps: initializing one or more base stations, transmitting the information of a control function to the server, transmitting commands with control parameter configuration to the one or more base stations. The one or more base stations separate the control function and data function for communication protocols.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority benefits of U.S. provisional application Ser. No. 62/305,539, filed on Mar. 9, 2016 and Taiwan application serial no. 105121179, filed on Jul. 5, 2016. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification. 
     
    
     TECHNICAL FIELD 
       [0002]    The present application relates to a server and a base station of a radio network, a method of accessing a radio network, and non-transitory computer-readable storage medium. 
       BACKGROUND 
       [0003]    The whole world is engaged to promote next generation 5G (5th generation mobile networks or 5th generation wireless systems). Facing the challenge of rapid increasing wireless data amount, the telecom providers build a large number of small cells, for example, Ultra Dense Network (UDN), to provide the transmission requirements of users. The main problem of the UDN is the interference (management) via coordination. The telecom providers provide Centralized Cloud Radon Access Network (Cloud-RAN or C-RAN) to manage the coordination among small cell. Please refer  FIG. 1 . A typical radio network is shown in FIG.  1 , in this architecture, the front-end has Remote Radio Heads (RRH) and a RRH antenna and for simple analog and digital signal conversion. A RRH is connected to the rear end consisting of a Base Band Unit (BBU) and a 5G core network. The received signals are transmitted to the base band unit, and handle any interference among the small cell coverages of the user equipment, for instance mobile phones, and the resources are effective sharing used to reduce cost. 
         [0004]    Owing to fronthaul with analog to digital converter (ADC) is between RRH and server with BBU, the requirements of transmission speed grow ten times. In order to decrease the transmission requirements, the ideas are proposed to move part of the functions of protocol layers to RRH and then retransmit to the server with BBU, for example, in  FIG. 2 , small cell function splits are proposed by Small Cell Forum. If more functions of protocol layers were in RRH, then less transmission requirements need to be transmitted to the server with BBU. But, coordination would lower the system performance owing to the interference among multiple RRHs, i.e., antenna/base station. 
         [0005]    Currently, solutions for the high transmission requirements of front-end in centralized C-RAN are separate protocol layers, for example, part of protocol layers are in RRH, base station or small cell, and the other part pf protocol layers are in server with BBU. Coordination would lower the system performance owing to the interference between antenna and base stations and influence the connection requirements for front-end.  FIG. 3  is a diagram illustrating the tradeoff between coordination and fronthaul traffic requirements, according to an exemplary embodiment. 
       SUMMARY 
       [0006]    One exemplary embodiment of the present disclosure relates to a server in a radio network. A server in a radio network includes: a control determination module to initialize one or more base stations; and a control information module to collect the information of a control function from one or more base stations, and the control determination module gives commands with control parameter configuration to the one or more base stations; wherein the one or more base stations separate the control function and a data function for communication protocols. 
         [0007]    Another exemplary embodiment of the present disclosure relates to a base station in a radio network. A base station in a radio network includes: an executor gets initialization actions from a server; and a control information report transmits information of control functions to the server; wherein the base station separates the control function and data function for communication protocols. 
         [0008]    Yet another exemplary embodiment of the present disclosure relates to a method for accessing a radio network. A method for accessing a radio network includes: initializing one or more base stations; transmitting the information of a control function to a server; and transmitting commands of control parameter configuration to the one or more base stations; wherein the one or more base stations separate the control function and data function for communication protocols. 
         [0009]    One more exemplary embodiment of the present disclosure relates to a non-transitory computer-readable storage medium. A non-transitory computer-readable storage medium embodying a computer program product, the computer program product comprising instructions configured to cause a computing device to perform the above method. 
         [0010]    The foregoing will become better understood from a careful reading of a detailed description provided herein below with appropriate reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a block diagram illustrating a typical radio network, according to an exemplary embodiment. 
           [0012]      FIG. 2  is a block diagram illustrating small cell function splits are proposed by Small Cell Forum, according to an exemplary embodiment. 
           [0013]      FIG. 3  is a diagram illustrating the tradeoff between coordination and fronthaul traffic requirements, according to an exemplary embodiment. 
           [0014]      FIG. 4-1  is a diagram illustrating the Long Term Evolution (LTE) communications protocol stack, according to an exemplary embodiment. 
           [0015]      FIG. 4-2  is a diagram illustrating the WiFi communications protocol stack, according to an exemplary embodiment. 
           [0016]      FIG. 5  is a diagram illustrating separation of data and control function, according to an exemplary embodiment. 
           [0017]      FIG. 6  is a diagram illustrating the operations between the server and the base station, according to an exemplary embodiment. 
           [0018]      FIG. 7  is a diagram illustrating the operations of the server, according to one exemplary embodiment. 
           [0019]      FIG. 8  is a diagram illustrating the operations of the base station, according to one exemplary embodiment. 
           [0020]      FIG. 9  is a diagram illustrating the detail operations of the base station, according to one exemplary embodiment. 
           [0021]      FIG. 10  is a diagram illustrating the detail operations of the server, according to one exemplary embodiment. 
           [0022]      FIG. 11  is a diagram illustrating the performance comparison with current technique, according to some exemplary embodiments. 
           [0023]      FIG. 12  is a diagram illustrating the computation details, according to one exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0024]    Below, exemplary embodiments will be described in detail with reference to accompanying drawings so as to be easily realized by a person having ordinary knowledge in the art. The inventive concept may be embodied in various forms without being limited to the exemplary embodiments set forth herein. Descriptions of well-known parts are omitted for clarity, and like reference numerals refer to like elements throughout. 
         [0025]    Our disclosure provides a network similar to a software defined network to separate control function and data function in centralized Cloud Radio Access Network (C-RAN). Control function might be executed in a server in Base Band Unit (BBU), radio network, C-RAN, the server in Ultra dense Network (UDN) or the server with BBU—those are the server in this disclosure. Data function might be executed in Base Station, a micro cell, a Small Cell, a Pico Cell, Evolved NodeB (eNB) or Remote Radio Head (RRH)—those are the base station in this disclosure. Fronthaul doesn&#39;t need to transmit a huge amount of data in our disclosure, but also could utilize Tight Coordination, for example, Network Multi-input Multi-output (Network MIMO) could be used to reduce interference and to increase the system performance. Base stations might exchange data mutually. 
         [0026]    The Long Term Evolution (LTE) communications protocol stack is shown in  FIG. 4-1 , consisting of five layers, from bottom to top, the Physical Layer (PHY), the Media Access Control (MAC) layer, the Radio Link Control (RLC) layer, the Packet Data Convergence Protocol (PDCP) layer, and the Radio Resource Control (RRC) layer. In each layer, a blank circle represents control information, and a dark circle represents data information. In the preferred embodiment of the present invention, control information and data information are separately processed in each layer. In other embodiments, the separation of control and data information might be processed in predetermined layers only, singly or multiply. 
         [0027]    For examples of the control and data function separation, in the Physical Layer (PHY), the control information is Channel Estimation, and the data is a Fast Fourier Transform (FFT) and Turbo Code. In the Media Access Control (MAC) layer, the control information is the Scheduling, the data is the Hybrid Automatic Retransmission Request (HARQ) and Scheduler. In the Radio Link Control (RLC) layer, the control information includes the Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM), and the data information is the Segmentation and Reassembly information. In the Packet Data Convergence Protocol (PDCP) layer, the control information is a Header Compression Control and the data information is a Robust Header Compression (ROHC) and Ciphering. In the Radio Resource Control (RRC), the control information is a Handover Management and System Information Block (SIB) and the data information is the Abstract Syntax Notation One (ASN.1). 
         [0028]    The present invention discloses a communication system having a base station and a server wherein control functions are executed in the server and data functions are executed in the base station. Such separate executions will decrease the fronthaul traffic of the communication system. In the preferred embodiment of the present invention, the separate executions are performed on a LTE protocol stack. The separate executions can be performed wholly or individually on the LTE protocol stack, with a preferred embodiment performing the separations on all the layers of the LTE protocol stack. Another embodiment discloses the separate executions performed on one or more of the layers of the LTE protocol stack. 
         [0029]    The WiFi communications protocol stack is shown in  FIG. 4-2 , two layers for example, from bottom to top, the Physical Layer (PHY) and the Data Link Layer. In each layer, a blank circle represents control information, and a dark circle represents data information. In the preferred embodiment of the present invention, control information and data information are separately processed in each layer. In other embodiments, the separation of control and data information can be processed singly or in a plurality of predetermined layers. 
         [0030]    For examples of the control and data function separation, in the Physical Layer (PHY), the control information is Pseudo-Random Number for Hopping Sequence, and the data is a Frequency-Hopping Spread Spectrum (FHSS). In the Data Link layer, the control information is the Network Allocation Vector (NAV) or Exponential Backoff Window Size, the data information is the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). 
         [0031]    In another embodiment of the present invention, the separate executions of control and data are performed on a WiFi protocol stack. In this embodiment, the separate executions are performed on at least one of the layers of the WiFi protocol stack, and in another embodiment the separate executions are performed on all the layers of the WiFi protocol stack. 
         [0032]    In our disclosure, the control and data separation might be arbitrary, for example, only in the physical layer, in the physical layer and media access layer, or in all of the protocol layers.  FIG. 5  is the separation example for LTE. Block  510  and  520  represent control function and data function respectively. The interface between server and control function  510  is BC (not illustrated in  FIG. 5 ). Control function  510  transmits control information by control logic interface SC (not illustrated in  FIG. 5 ) Data function  520  transmits data information by data logic interface BD (not illustrated in  FIG. 5 ). Control functions are handled by server, and base stations handle the data and control function separation. Control function  510  and data function  520  are saved in non-transitory computer-readable storage medium. 
         [0033]      FIG. 6  illustrates one embodiment of the present invention, for example, the block operation functions between base station and server. The server includes a control function determination  101 , and a control information collector  102 . The server handles the control functions. The control function determination  101 , and the control information collector  102  could be saved in non-transitory computer-readable storage medium. Base station includes a control information report  103  and an executor  104 . Base Station could separate control and data functions. The server could use a control logic interface to communicate control information to the control logic interface in base station. The data logic interface in the base station could communicate data information to the other base stations by their data logic interface. 
         [0034]    In one embodiment of our disclosure, the control functions of one or multiple protocol layers in a plurality of base stations are extracted to form a tightly centralized C-RAN, for example, the Inter-cell Interference coordination, or two base stations serving one cell phone (network MIMO), Two base stations could be three base stations or any combinations of base stations. 
         [0035]    The operations between the server and the base station are illustrated in  FIG. 6 . In step  201 , the server might initialize one or more base stations. In step  202 , the one or more base stations might transmit control information to the server. In step  203 , the server gives commands with control parameter configurations to the one or more base stations. 
         [0036]      FIG. 7  illustrates one embodiment of our disclosure with the operations of the server. Step  201  might be executed by the control function determination  101  to initialize one or more base stations. In step  202 , the control information collector  102  in server might collect the control information from the control information report  103  in the base station. In step  203 , the control function determination  101  in the server according to the control information from step  202  gives commands with control parameter configurations to the executor  104  of one or a plurality of base stations. 
         [0037]    In one embodiment of our disclosure, the server calculates a relationship according to neighbor&#39;s relationship among a plurality of the base stations and transmits a calculating result to the base station. Network MIMO could be used to reduce interference via tight coordination and the system performance might be improved. The relationship might be executed by the channel information (control information) from the base station with the interference among base stations or the relations among a plurality of base stations and transmit to the base station. 
         [0038]      FIG. 8  illustrates one embodiment of our disclosure with the operations of the base stations. The executor  104  in the base station gets initialization actions from the server. In step  202 , the control information report  103  in the base station transmits control information to the control information collector  102  in server. In step  203 , the executor  104  of one or more base stations gets the commands with control parameter and executes the commands. 
         [0039]    In some embodiments of our disclosure, the server might connect with a plurality of base station with same structure in  FIG. 8 . Non-transitory computer-readable storage medium might be saved in computer program products, for example, the server or the base station in our disclosure. The computer program products include instructions which are configured to execute the operations of  FIG. 8 . 
         [0040]    The following might use LTE as one embodiment of the present disclosure. The present disclosure is not limited to LTE. The present disclosure might be used to WiMAX and the other protocols. According to  FIG. 9 , the control information report  103  of the base station will vertically transmit the control parameter configuration of control function of the Physical layer, the Media Control Access layer, the Radio Link Control layer, the Packet Data Convergence Protocol (PDCP) layer, or the Radio Resource Control (RRC) layer to the server. Examples of such control signals are Channel Estimation, Scheduling, the Transparent Mode (TM), Unacknowledged Mode (UM), and Acknowledged Mode (AM). The control receptor  301  receives commands with control parameter configuration from the server. The control receptor  301  determines a layer of the communication protocols according to the commands with control parameter configuration, and transmits the commands with control parameter configuration to the layer of the communication protocols 
         [0041]    The control function collector  102  in the server might collect the information related to control function and send to the control function determination  101 . The control function determination  101  might estimate the performance and give commands with the control parameter configuration to the base stations. For example, performance estimation might be the maximum transmission traffic among the server, the base station and the user according to the MIMO parameter of the base station. Another example is the minimum energy among the server, the base station and the user according to the power parameter of the base station. The performance estimation might be a weight of a plurality parameters. 
         [0042]    In  FIG. 10 , the control function collector  102  in the server includes a control function handler  302 . According to the User Identifier (UEid) and Base Station Identifier (BSid), the control function handler  302  might determine the control information to the user or to the base station. 
         [0043]    The performance comparison with current technique might be illustrated in  FIG. 11 . According to  FIG. 11 , the present disclosure might reduce the transmission traffic of the front-end greatly and still able to execute the tight coordination, for example, Network MIMO.  FIG. 12  illustrates the computation details. 
         [0044]    In the present disclosure, LTE is used for one embodiment. The concept of the present disclosure might be used to the other protocols, for example, IEEE 802.11, IEEE 802.16, WiMAX or the other protocols. 
         [0045]    It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosure. It is intended that the specification and examples be considered as exemplary embodiments only, with a scope of the disclosure being indicated by the following claims and their equivalents.