Loading patent…
AssigneeHitachi, Ltd.
InventorsTomoyuki Harada, Takuji Hamada, Hideaki Masuko, Shinichi Hanada, Yoshiaki Adachi, Hisao Ogawa
Estimating the term…
Occurrence of significant difference of transmission rate between communication zones can be prevented to maintain the transmission rate of overall network uniform. The radio network system includes a plurality of radio communication control units are connected with each other via radio main line, and each radio communication control unit has a communication function with at least one radio communication terminal arranged within own communication area. Each of the radio communication control units includes means for broadcasting a transmission rate restriction demand to all of other radio communication control units and all of radio communication terminals when data amount stored in a transmission and reception buffer exceeds a predetermined threshold value, and means for lowering a transmission rate when a transmission rate restriction demand is received from any other radio communication control unit within a predetermined period and for increasing the transmission rate when no transmission rate restriction demand is received from any other radio communication control unit.
A radio network system comprising:
A method of operating a radio network system which includes:
A radio network system comprising:
A radio communication control unit comprising:
A radio communication control unit as set forth in claim 31 wherein said transmission and reception buffer comprises N separate buffers and a threshold value for lowing said transmission rate is set at N/X, where X is an integer greater than one and less than N.
A radio communication control unit as set forth in claim 32 wherein X is equal to 2.
A radio communication control unit as set forth in claim 32 wherein X is equal to 3.
A radio communication terminal comprising:
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
From the US filing history. Foreign family members aren’t listed.
Backward citations are indexed for grants only.
Systems modifying transmission characteristics according to link quality, e.g. power backoff: by adapting the transmission rate
Characterised by the signalling: transmission of mode-switching indication
Digital communication
Term end not estimated
The present invention relates to a radio network system, in which a plurality of radio communication control equipments respectively having communication function with a plurality of radio terminals and connected with each other via a radio main line.
In the recent years, according to advancement of radio communication technology, it has been frequently established a radio communication network for data transmission between terminals since it does not require engineering work for cable connection associated with modification of layout in an office, a store, a factory or the like. However, in order to perform communication in wide area, a main line of the network is constructed as a wired network with an optical fiber, coaxial cable or so forth so as to provide sufficient reliability. Such wired main line is connected to a communication control apparatus. Then, a plurality of radio communication terminals are typically connected to the communication control apparatus in tree connection, bus connection, star connection. As such type of network, it has been known a BREEZNET PROSeries of BREEZECOM Ltd.
It has been desired to form the main line of the network as radio communication line for reducing cabling cost, maintenance cost and so forth. However, when radio network is employed as main line, zones where retransmission process is frequently required for interference of reflected radio wave from ceiling, wall or so forth, environmental noise or so forth, to cause significant fluctuation of transmission rate between communication zones.
The present invention will be understood more fully from the detailed description given hereinafter and from the accompanying drawings of the preferred embodiment of the present invention, which, however, should not be taken to be limitative to the invention, but are for explanation and understanding only.
In the drawings:
FIG. 1 is a block diagram showing the preferred embodiment of a radio communication control unit to be used in a radio network according to the present invention;
The present invention will be discussed hereinafter in detail in terms of the preferred embodiment of a radio network system of the present invention with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be obvious, however, to those skilled in the art that the present invention may be practiced without these specific details. In other instance, well-known structure are not shown in detail in order to avoid unnecessary obscurity of the present invention.
FIG. 2 shows a general construction of a radio network system, to which the present invention is applied. Here, discussion will be given in terms of a ring-shaped radio network system.
Radio communication control units 100, 110, 120 and 130 form a ring-shaped radio network system. For each of the radio communication control units 100, 110, 120 and 130, unique address is assigned. Also, unique addresses are assigned for radio communication terminals 107, 108, 117 and 118. The address may be assigned upon establishing the communication system, or, in the alternative, may be assigned dynamically upon communication.