A better understanding of the present invention will become apparent from the following detailed description of example embodiments and the claims when read in connection with the accompanying drawings, all forming a part of the disclosure of this invention. While the following written and illustrated disclosure focuses on disclosing example embodiments of the invention, it should be clearly understood that the same is by way of illustration and example only and that the invention is not limited thereto. The spirit and scope of the present invention are limited only by the terms of the appended claims. The following represents brief descriptions of the drawings, wherein:
Reference will now be made in detail to the present embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.
In the portable Internet service system 100, a data communication service guaranteeing mobility may be provided even when the portable terminal 120 moves from a cell covered by a base station 110-1 to another cell covered by another base station 110-2. Similar to a mobile communication service, the portable Internet service system 100 supports a handover of the portable terminal 120 and allocates a dynamic Internet protocol (IP) address according to the movement of the portable terminal 120.
The base station 110-2 and a plurality of portable terminals 120-1, 120-2, and 120-3 communicate with each other in an orthogonal frequency division multiplexing access (OFDMA) method. The OFDMA method is a multiplexing method in which a frequency division method using subcarriers of a plurality of orthogonal frequencies as a plurality of subchannels and a time division multiplexing access (TDMA) method are combined. The OFDMA method is robust against multi-path fading and has a high data rate. However, other communication methods may also be employed, including code division multiple access (CDMA) and TDMA.
The IEEE 802.16e standard employs an adaptive modulation and coding (AMC) method that adaptively selects modulation and coding according to a channel state and a location of the portable terminal 120 to provide an appropriate data rate. Accordingly, when a plurality of users share a given capacity, transmission speed varies according to predetermined environments (i.e., a load of neighboring cells and a current channel state of a subscriber). However, aspects of the present invention may employ different standards, such as IEEE 802.11 or Bluetooth.
The uplink frame includes an uplink control symbol and uplink data. The uplink data includes a slot, a tile, and a bin. A receive-to-transmit transition gap (RTG) of 40.4 ms is provided at an end part of the uplink frame as a guard time to divide uplink and downlink frame transmission times. The downlink frame includes a downlink preamble and downlink data. Like the uplink data, the downlink data also includes a slot, a group, and a bin. A transmit-to-receive transition gap (TTG) of 121.2 ms is provided at an end part of the downlink frame as the guard time to divide the uplink and downlink frame transmission times.
The physical layer L1 performs a wireless communication function that is performed by a conventional physical layer. The wireless communication function includes modulation/demodulation and coding functions. In addition, the physical layer L1 includes a modem to convert and to protect data in the wireless environment, as well as a transmitting/receiving unit including a radio frequency (RF) unit to wirelessly transmit and receive data.
The MAC layer L2 may include a privacy sublayer L21, a MAC common part sublayer L22, and a service specific convergence sublayer L23. The privacy sublayer L21 performs authentication, security key exchange, and encryption functions for the portable terminal 120. The authentication function of the portable terminal 120 is performed in the privacy sublayer L21 and a user authentication function is performed in an upper layer (not shown). The MAC common part sublayer L22, which is a core part of the MAC layer, performs functions relating to system access, bandwidth allocation, and connection establishment and management operations. The service specific convergence sublayer L23 performs payload header suppression and quality of service (QoS) mapping functions for sequential data communication.
The TCP/IP layer L3 connects each system and uses the TCP protocol to perform a data transmission function. The application layer L4 includes an application program using the network, such as HyperText Transfer Protocol (HTTP) for web browsing.
The plurality of portable terminals 520-1, 520-2, and 520-3 access the base station 510 at block S402. When power is supplied to a first portable terminal 520-1, or the first portable terminal 520-1 enters a cell of the base station 510, the base station 510 establishes a downlink synchronization with the first portable terminal 520-1. Once the downlink synchronization is established, the first portable terminal 520-1 obtains an uplink parameter and a ranging operation is performed between the first portable terminal 520-1 and the base station 510. In addition, access control functions, including authentication, registration, address allocation, and traffic connection establishment and change, are performed in order for the first portable terminal 520-1 to access the portable Internet service.
When a second portable terminal 520-2 (hereinafter referred to as a “receiving terminal”) transmits a download request to download data stored in the first portable terminal 520-1 (hereinafter referred to as a “transmitting terminal”) at block S404, the base station 510 determines at block S406 whether uplink data transmitted from the transmitting terminal 520-1 is received by the receiving terminal 520-2 in a peer-to-peer fashion. The base station 510 determines whether the transmitting terminal 520-1 and the receiving terminal 520-2 are positioned within an area of the base station 510 and determines whether the transmitting terminal 520-1 and the receiving terminal 520-2 are positioned within an area in which the transmitting terminal 520-1 and the receiving terminal 520-2 may receive data in the peer-to-peer method. While the first portable terminal 520-1 is a transmitting terminal and the second portable terminal 520-2 is a receiving terminal, it is understood that according to other aspects of the invention, the first and second portable terminals 520-1 and 520-2 may perform both transmitting and receiving functions.
When the receiving terminal 520-2 has a parameter different from an existing parameter to perform a peer-to-peer function, the base station 510 determines whether the receiving terminal 520-2 may receive the data in the peer-to-peer method. If peer-to-peer transmission may not be performed between the transmitting terminal 520-1 and the receiving terminal 520-2, the base station 510 receives the uplink data from the transmitting terminal 520-1, adds the uplink data to the downlink frame, and transmits the downlink frame to the receiving terminal 520-2 at block S408. If the peer-to-peer transmission may be performed between the transmitting terminal 520-1 and the receiving terminal 520-2, the base station 510 transmits a control signal to the transmitting terminal 520-1 so that the transmitting terminal 520-1 transmits the uplink data. The base station 510 transmits a control signal to the receiving terminal 520-2 to receive the uplink data from the transmitting terminal 520-1 at block S410.
As shown in
As shown in
Returning to
If the receiving terminal 520-2 continuously receives the data from the transmitting terminal 520-1, an exclusive channel may be formed. The base station 510 may repeat block S410 and transmit the control signal to the transmitting terminal 520-1 and the receiving terminal 520-2.
The connection C1 is not a physical connection relationship but a logical connection relationship. The connection C1 may be defined as a mapping relationship between MAC peer layers of the transmitting and receiving terminals 520-1 and 520-2 to transmit traffic of one service flow. A parameter or a message defined on the connection C1 defines a function between the MAC peer layers. The parameter or the message is formed as a frame to be transmitted through the physical layer and the frame is analyzed so that the MAC layer performs a function corresponding to the parameter or the message.
In the example embodiment of the present invention as shown in
As described above, according to aspects of the present invention, a peer-to-peer transmission to increase wireless transmission efficiency of a network may be performed.
In addition, since a downlink data transmission process additionally caused by uplink data transmission is omitted, the transmission efficiency of the network may be maximized.
Peer-to-peer transmission routines according to aspects of the present invention may be recorded in computer-readable media including program instructions to implement various operations embodied by a computer. The media may also include, alone or in combination with the program instructions, data files, data structures, and the like. Examples of computer-readable media include magnetic media such as hard disks, floppy disks, and magnetic tape; optical media such as CD ROM disks and DVD; magneto-optical media such as optical disks; and hardware devices that are specially configured to store and perform program instructions, such as read-only memory (ROM), random access memory (RAM), flash memory, and the like; and a computer data signal embodied in a carrier wave comprising a compression source code segment and an encryption source code segment (such as data transmission through the Internet). Examples of program instructions include both machine code, such as produced by a compiler, and files containing higher level code that may be executed by the computer using an interpreter. The described hardware devices may be configured to act as one or more software modules in order to perform the operations of the above-described embodiments of the present invention.
While there have been illustrated and described what are considered to be example embodiments of the present invention, it will be understood by those skilled in the art and as technology develops that various changes and modifications, may be made, and equivalents may be substituted for elements thereof without departing from the true scope of the present invention. Many modifications, permutations, additions and sub-combinations may be made to adapt the teachings of the present invention to a particular situation without departing from the scope thereof. For example, the base station 110 may comprise a receiving unit to receive the uplink signals from the transmitting terminal 520-1, a transmission unit to transmit downlink data and control signals to the transmitting terminal 520-1 and the receiving terminal 520-2, and a controller to establish the peer-to-peer communication between the transmitting terminal 520-1 and the receiving terminal 520-2. Similarly, the transmitting and receiving terminals 520-1 and 520-2 may comprise communication units to communicate with the other terminal and with the base station as well as a controller to establish the peer-to-peer communication. The base station 110, transmitting terminal 520-1, and receiving terminal 520-2 may comprise other components. The functionality of one or more of the above components may also be combined into a single component. Accordingly, it is intended, therefore, that the present invention not be limited to the various example embodiments disclosed, but that the present invention includes all embodiments falling within the scope of the appended claims.
Number | Date | Country | Kind |
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2006-100329 | Oct 2006 | KR | national |