Patent Application
20080159253
1. Field of the Invention
The present invention relates to a method and system for increasing link quality in a multihop system. The present invention further relates to combining signals read from a base system and a relay system.
2. Introduction
A greater portion of the population than in even the recent past has adopted wireless technology to service their communication needs. This increased penetration of the market is due to wireless communications ability to increase the mobility of the user and increase the access of these users. Homes and offices have switched from having wired local area networks (LAN) to wireless LANs that allow for a number of computers to be interconnected at a fraction of the cost and upkeep. In telephony, most people of the younger generations have foregone the use of landlines in the home in favor of cellular technology that allows them to keep in greater contact with their peers at a fraction of the cost. This trend is even more pronounced outside the United States, where the cellular technology has greater penetration due to more congested land use and lack of costly landline infrastructure.
This wireless revolution is not without its drawbacks. Wireless communication is basically unstable. Techniques such as forward error correction, retransmission, and many others are employed to improve reliability of communication. To gain a reliability of communication, using more resources like transmission power or wide frequency band is one of the solutions. However, using transmission power and frequency band comes with its own limitations. More robust link quality is a constant issue in wireless communications. The same is true for the relay communication environment. Thus, techniques that are more effective than the conventional wireless systems are needed.
A method, apparatus, and electronic device for improving link quality in a multihop system are disclosed. The method may include reading with a mobile system a first transmission between a base system and a first relay system; reading with the mobile system a second transmission of an altered first transmission between the first relay system and the mobile system; and combining the first transmission and the second transmission to produce a first signal. Additionally, the method may be used for uplink communication as well as downlink communication, with the base system reading transmissions from both the mobile system and the relay station.
In order to describe the manner in which the above-recited and other advantages and features of the invention can be obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
a-b illustrate in a block diagram methods of error correction.
a-b illustrate embodiments of multihop systems using the present invention.
a-b illustrate attenuated and optimum localities for the present invention.
a-d illustrate one embodiment of constellation change in the present invention.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The features and advantages of the invention may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth herein.
Various embodiments of the invention are discussed in detail below. While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without parting from the spirit and scope of the invention.
The present invention comprises a variety of embodiments, such as a method, an apparatus, and an electronic device, and other embodiments that relate to the basic concepts of the invention. The electronic device may be any manner of mobile device, relay station or other wireless communication device.
A method, telecommunication apparatus, and electronic device for improving link quality in a multihop system are disclosed. A mobile system may read a first transmission between a base system and a first relay system. The mobile system may read a second transmission of an altered first transmission between the first relay system and the mobile system. The mobile system may then combine the first transmission and the second transmission to produce a first signal. The first transmission may be altered using constellation change, puncture pattern change, changes to the randomizer, and changes to the interleaver bit.
The use of relay stations may be used to improve link quality.
a illustrates in a block diagram a method 300 of hybrid automatic repeat request (HARQ). The base station 210 transmits a downlink frame 220 to the mobile station 250. If the mobile station 250 fails to receive the data correctly, the mobile station transmits a negative acknowledgment 310 to the base station 210. The base station 210 transmits data to the mobile station 250 again. The mobile station may combine the first received data and the second received data. If the transmitted symbol was the same, the method used is referred to as Chase combining, or HARQ.
b illustrates in a block diagram a combination signal check 320 using the “eavesdropping” signal 330 between the base 210 and the relay station 230. The mobile station 250 receives two transmissions from the base station 210 and the relay station 230. The timing differential for each signal will be different. Normally received power from the base station 210 transmission is not stronger than the received power from the relay station 230. The mobile station 250 may still combine the signals.
a illustrates an embodiment 400 in which the mobile relay station 250 is combining the base station 210 transmissions and the relay station 230 transmissions.
As shown by
As with the base station 210, a MAC SDU 722 may provide a data signal to be transmitted. A header block 724 may add the header. A CRC encoder 726 may add a CRC to the data signal. A randomizer 728 may randomize the data bit. The FEC encoder 730 may FEC encode the data. A bit interleaver 732 may order change the bits. A modulator 734 may modulate the data for transmission. A STP converter 736 may convert the data stream from serial to parallel. An IFFT block 738 may apply an IFFT to the data stream. A GI block 740 may add a GI. The relay station 230 may then transmit the signal over the radio frequency transmitter 702.
When the relay station 230 relays data, the relay station 230 may change transmission power or FEC method, like adaptive modulation coding (AMC) or puncture rate, to avoid interference or to place a link adaptation. However, the relay station 230 does not change transmission patterns, such as FEC (like convolutional code or turbo code) and puncture patterns, because changing FEC does not effect favorably on the next stations directly.
The transmission patterns may be changed to obtain more diversity gain. Diversity gain obtained in the combination is different from quadrature amplitude modulations (QAM) symbol positions. The transmission patterns may be changed when the symbol pattern and constellation are same or similar in the relay link and the access link. The transmission patterns may be changed at either the modulation block (constellation mapping change) 734, the FEC encoding block (puncture pattern change) 730, the bit interleaver 732, or the randomizer 728.
a-d illustrate one embodiment of constellation change 1000 in the present invention.
The controller/processor 1510 may be any programmed processor known to one of skill in the art. However, the decision support method can also be implemented on a general-purpose or a special purpose computer, a programmed microprocessor or microcontroller, peripheral integrated circuit elements, an application-specific integrated circuit or other integrated circuits, hardware/electronic logic circuits, such as a discrete element circuit, a programmable logic device, such as a programmable logic array, field programmable gate-array, or the like. In general, any device or devices capable of implementing the decision support method as described herein can be used to implement the decision support system functions of this invention.
The memory 1520 may include volatile and nonvolatile data storage, including one or more electrical, magnetic or optical memories such as a RAM, cache, hard drive, CD-ROM drive, tape drive or removable storage disk. The memory may have a cache 1525 to speed access to specific data.
The Input/Output interface 1550 may be connected to one or more input devices that may include a keyboard, mouse, pen-operated touch screen or monitor, voice-recognition device, or any other device that accepts input. The Input/Output interface 1550 may also be connected to one or more output devices, such as a monitor, printer, disk drive, speakers, or any other device provided to output data.
The network interface 1560 may be connected to a communication device, modem, network interface card, a transceiver, or any other device capable of transmitting and receiving signals over a network. The components of the computer system 1500 may be connected via an electrical bus 1570, for example, or linked wirelessly.
Client software and databases may be accessed by the controller/processor 1510 from memory 1520 or through the database interface 1540, and may include, for example, database applications, word processing applications, the client side of a client/server application such as a billing system, as well as components that embody the decision support functionality of the present invention. The computer system 1500 may implement any operating system, such as Windows or UNIX, for example. Client and server software may be written in any programming language, such as ABAP, C, C++, Java or Visual Basic, for example.
Although not required, the invention is described, at least in part, in the general context of computer-executable instructions, such as program modules, being executed by the electronic device, such as a general purpose computer. Generally, program modules include routine programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Moreover, those skilled in the art will appreciate that other embodiments of the invention may be practiced in network computing environments with many types of computer system configurations, including personal computers, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like.
Embodiments may also be practiced in distributed computing environments where tasks are performed by local and remote processing devices that are linked (either by hardwired links, wireless links, or by a combination thereof through a communications network.
Embodiments within the scope of the present invention may also include computer-readable media for carrying or having computer-executable instructions or data structures stored thereon. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions or data structures. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or combination thereof to a computer, the computer properly views the connection as a computer-readable medium. Thus, any such connection is properly termed a computer-readable medium. Combinations of the above should also be included within the scope of the computer-readable media.
Computer-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. Computer-executable instructions also include program modules that are executed by computers in stand-alone or network environments. Generally, program modules include routines, programs, objects, components, and data structures, etc. that perform particular tasks or implement particular abstract data types. Computer-executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represents examples of corresponding acts for implementing the functions described in such steps.
Although the above description may contain specific details, they should not be construed as limiting the claims in any way. Other configurations of the described embodiments of the invention are part of the scope of this invention. For example, the principles of the invention may be applied to each individual user where each user may individually deploy such a system. This enables each user to utilize the benefits of the invention even if any one of the large number of possible applications do not need the functionality described herein. It does not necessarily need to be one system used by all end users. Accordingly, the appended claims and their legal equivalents should only define the invention, rather than any specific examples given.
