Abstract:
A repeating method for a wireless communication system which provides time and space diversities, and an apparatus thereof are disclosed. The method of repeating a forward link communication signal for a wireless communication system includes the steps of: a) transmitting the forward link communication signal through a first transmitting antenna; b) delaying the forward link communication signal for a predetermined time period; and c) transmitting a delayed forward link communication signal which is generated by step b) through a second transmitting antenna. According to the method, when repeating forward and reverse link communication signals, time and space diversities are respectively provided to the base station and the mobile stations.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a wireless communication system, more particularly to a repeating method for a wireless communication system which provides time and space diversities, and an apparatus which performs the method. 
     2. Prior Art 
     In a wireless communication system, a repeater is generally used for extending a service coverage of a base station and enhancing system performance in a service area. 
     When a mobile station is placed at in-building, particularly an upper floor, the receiving sensitivity of the mobile station is degraded because of interference by adjacent base stations. This degradation causes problems such as a call drop, call setup and handoff failures, etc. 
     Furthermore, because mobile stations, as consumer products, are tightly limited, improvements in performance by requesting mobiles station providers to manufacture mobile stations with improved receiving sensitivity is limited. Therefore, service providers install repeaters, distributed antennas, or the like into buildings to service a wireless communication into buildings. 
     However, it is very expensive to install the repeaters or distributed antennas into all buildings. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved repeating method for a wireless communication system and an apparatus thereof. 
     It is another object of the present invention to provide a repeating method which can improve service quality in buildings without installing repeaters or distributed antennas into the buildings. 
     It is a further object of the present invention to provide a method of repeating a forward link communication signal which can provide time and space diversities to receiving sites and an apparatus which can perform the method. 
     In order to achieve the above objects, a method according to one aspect of the present invention includes a) transmitting a forward link communication signal through a first transmitting antenna; b) delaying the forward link communication signal for a predetermined time period; and c) transmitting a delayed forward link communication signal which is generated by step b) through a second transmitting antenna. 
     An apparatus according to another aspect of the present invention includes means for transmitting a forward link communication signal through a first transmitting antenna; means for delaying the forward link communication signal for a predetermined time period; and means for transmitting a delayed forward link communication signal which is generated by the delaying means through a second transmitting antenna. 
     According to the present invention, a method and an apparatus for repeating a forward link communication signal are provided, which can provide the time and space diversities to the sites of receiving the forward link communication signal. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention will be better understood and its various objects and advantages will be more fully appreciated from the following description taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a block diagram for showing a base station employing a repeater according to one embodiment of the present invention; 
     FIG. 2 is a block diagram for illustrating the repeater depicted in FIG. 1.; and 
     FIG. 3 is a flow chart for illustrating the process of repeating a forward link communication signal of the repeater. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Preferred embodiments of the present invention will be illustrated below with reference to the accompanying drawings. 
     FIG. 1 is a block diagram for showing a base station  100  employing a repeater according to one embodiment of the present invention. 
     Referring to FIG. 1, the base station  100  includes a communication channel processing part  200 , a transmitting/receiving part  300 , and a repeater  400  according to the present invention. 
     The communication channel processing part  200  generates a forward link communication signal, and processes reverse link communication signals from the transmitting/receiving part  300  and the repeater  400 . For example, if the base station is an IS-95 base station, the communication channel processing part  200  generates a baseband digital signal of having traffic and overhead information and converts the baseband digital signal into an analog signal thereby to generate the forward link communication signal. 
     The transmitting/receiving part  300  amplifies the forward link communication signal and transmits the amplified forward link communication through a transmitting antenna  311 . Further, the transmitting/receiving part  300  detects reverse link communication signals from signals received by each of both the first receiving antenna  331  and the second receiving antenna  351 , and provides the reverse link communication signals to the communication channel processing part  200 . 
     Preferably, the transmitting/receiving part  300  includes a transmitting part  310 , and the first and second receiving parts  330  and  350 . The transmitting part  310  amplifies the forward link communication signal and transmits the amplified forward link communication signal through the transmitting antenna  311 . The first and second receiving parts  330  and  350  detect the reverse link communication signals from the signals received by the first receiving antennas  331  and  351 , and provide the reverse link communication signals to the communication channel processing part  200 , respectively. 
     The repeater  400 , according to the present invention, includes a divider  500 , a direct path transmitting/receiving part  600 , and a multi-path transmitting/receiving part  700 . 
     The divider  500  provides the forward link communication signal to the direct path transmitting/receiving part  600  and a multi-path transmitting/receiving part  700 , respectively. 
     The direct path transmitting/receiving part  600  transmits the forward link communication signal from the divider  500  through a first transmitting/receiving antenna  660 . And, the direct path transmitting/receiving part  600  detects a first reverse link communication signal from signals received by the first transmitting/receiving antenna  660 , and provides the first reverse link communication signal to the communication channel processing part  200 . 
     Preferably, as shown in FIG. 2, the direct path transmitting/receiving part  600  includes a first pre-amplifier  610 , a first attenuator  620 , a first linear power amplifier  630 , a first duplexer  640 , and first low noise amplifier  650 . 
     The first pre-amplifier  610  amplifies the forward link communication signal from the divider  500 , and provides a first amplified forward link communication signal to the first attenuator  620 . 
     The first attenuator  620  attenuates the first amplified forward link communication signal from the first pre-amplifier  610 , and provides a first attenuated forward link communication signal to the first linear power amplifier  630 . 
     The first linear power amplifier  630  linearly amplifies the first attenuated forward link communication signal from the first attenuator  620 , and transmits a first linear amplified forward link communication signal through the first duplexer  640  and the first transmitting/receiving antenna  660 . 
     The first duplexer  640  provides the first linearly amplified forward link communication signal to the first transmitting/receiving antenna  660 , and provides the first reverse link communication signal received by the first transmitting/receiving antenna  660  to the first low noise amplifier  650 . 
     The first low noise amplifier  650  amplifies the first reverse link communication signal from the first duplexer, and provides the first reverse link communication signal to the communication channel processing part  200 . 
     The multi-path transmitting/receiving part  700  delays the forward link communication signal from the divider  500  for a first predetermined time period in order to generate a delayed forward link communication signal, and transmits the delayed forward link communication signal through the second transmitting/receiving antenna  780 . Further, the multi-path transmitting/receiving part  700  delays a second reverse link communication signal received by the second transmitting/receiving antenna  780  for a second predetermined time period, and outputs the second reverse link communication signal to the communication channel processing part  200 . 
     Preferably, as shown in FIG. 2, the multi-path transmitting/receiving part  700  includes the first delay  710 , the second pre-amplifier  720 , the second attenuator  730 , the second linear power amplifier  740 , the second duplexer  750 , the second low noise amplifier  760 , and the second delay  770 . 
     The first delay  710  delays the forward link communication signal for the first predetermined time period to generate the delayed forward link communication signal, and provides the delayed forward link communication signal to the second preamplifier  720 . 
     The second pre-amplifier  720  amplifies the delayed forward link communication signal from the first delay  710  to generate the second amplified forward link communication signal, and provides the second amplified forward link communication signal to the second attenuator  730 . 
     The second attenuator  730  attenuates the second amplified forward link communication signal from the second pre-amplifier  720  to generate the second attenuated forward link communication signal, and provides the second attenuated forward link communication signal to the second linear power amplifier  740 . 
     The second linear power amplifier  740  linearly amplifies the second attenuated forward link communication signal from the second attenuator  730  to generate the second linearly amplified forward link communication signal, and provides the second linearly amplified forward link communication signal to the second duplexer  750 . 
     The second duplexer  750  provides the second linearly amplified forward link communication signal from the second linear power amplifier  740  to the second transmitting/receiving antenna  780  to transmit the second linearly amplified forward link communication signal through the second transmitting/receiving antenna  780 . Further, the second duplexer  750  provides the second reverse link communication signal received by the second transmitting/receiving antenna  780  to the second low noise amplifier  760 . 
     The second low noise amplifier  760  amplifies the second reverse link communication signal from the second duplexer  750  and provides the second amplified reverse link communication signal to the second delay  770 . 
     The second delay  770  delays the second amplified reverse link communication signal from the second low noise amplifier  760  for the second predetermined time period to generate the delayed reverse link communication, and provides the delayed reverse link communication signal to the communication channel processing part  200 . 
     Hereinafter, the operation of the repeater  400  according to the present invention will be described with reference to FIG.  3 . 
     FIG. 3 is a flow chart for illustrating the process of repeating a forward link communication signal of the repeater  400 . 
     First, describing the process of repeating the forward link communication signal, when the forward link communication signal is inputted from the communication channel processing part  200  to the divider  500 , the divider  500  provides the forward link communication signal to the direct path transmitting/receiving part  600  and the multi-path transmitting/receiving part  700 , respectively(S 1 ). 
     When the forward link communication signal is inputted to the direct path transmitting/receiving part  600 , the forward link communication signal is amplified and attenuated by the first pre-amplifier  610  and the first attenuator  620 (S 2 ). 
     On the other hand, the forward link signal which is inputted to the multi-path transmitting/receiving part  700  is delayed for the first predetermined time period by the first delay  710 (S 3 ). 
     Then, the delayed forward link communication signal is amplified and attenuated by the second pre-amplifier  720  and the second attenuator  730 (S 4 ). 
     The forward link communication signals which are amplified and attenuated by steps  2  and  4  are linearly amplified by the first and second linear power amplifiers  630  and  740 . And then, the forward link communication signals are transmitted through the first and second transmitting/receiving antennas  660  and  780 , respectively(S 5 ). 
     Describing the process of repeating the reverse link communication signal, the first reverse link communication received by the first transmitting/receiving antenna  660  is provided through the first duplexer  640  to the first low noise amplifier  650 . The first low noise amplifier  650  amplifies the reverse link communication signal and provides the first amplified reverse link communication signal to the communication channel processing part  200 . 
     On the other hand, the second reverse link communication signal received by the second transmitting/receiving antenna  780  is inputted through the second duplexer  750  to the second low noise amplifier  760 . The second low noise amplifier  760  amplifies the second reverse link communication signal and outputs the second amplified reverse link communication signal to the second delay  770 . Then, the second delay  770  delays the second amplified reverse link communication signal for the second predetermined time period and provides the delayed reverse link communication signal to the communication channel processing part  200 . 
     According to the present invention, when repeating forward and reverse link communication signals, time and space diversities are respectively provided to the base station and the mobile stations, such that the service quality of wireless communication system is enhanced. 
     While this invention has been particularly shown and described with reference to particular embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be effected therein without departing from the spirit and scope of the invention as defined by the appended claims.