MULTI CHANNEL COMMUNICATION SYSTEM FOR WIRELESS LOCAL LOOP COMMUNICATION
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION The present invention relates to a novel method of communication for wireless local loop communication systems, and more particularly to methods to optimally handle radio transmission and reception at a radio access node thereby minimizing interference internal and blocking problems. PREVIOUS TECHNIQUE Cellular systems operate on the principle of frequency reuse that gives a cellular operator the ability to offer a high radio traffic capacity. With higher radio traffic capabilities, more users per geographical area can use radio communication. The reuse of frequencies, which is a central concept in cellular communication, includes the reuse of the same frequency in a system many times in the handling of several calls. Time division multiple access ("TDMA") is a form of access technology that allows multiple users to occupy the same frequency spectrum. Each user of the cellular system shares the frequency assignment with other users who have time segment assignment during other periods. In a wireless local loop communication system that employs the TDMA standard of cellular communication, many users share the same frequency channel, each user receiving a single time segment. As traffic increases within each random access node, or cell site, the level of internal interference and signal blockage that occurs increases due to the number of users using the same carriers and the same time segment in carriers. neighbors. When a fixed access unit or a mobile station is making a call, the user has communication quality problems since several different factors affect the quality of the communication system such as, for example, internal interference, blocking, charging, Multiple trajectory propagation, dispersion and reflection. Accordingly, there is a need for methods that reduce these problems associated with the quality of the calls. PCS communication systems of the lower part of the prior art have attempted to solve the problem of internal system interference and blocking by the use of dynamic channel allocation. In order to maintain the clarity of the radio communication within the cellular network, a fixed access unit, or a mobile unit, explores the operating environment and selects all available channels. The results of the scan are then loaded into a history table in the order of their quality. The history table is updated at different time intervals to constantly monitor the condition of the various channels available for use. If a telephone or a mobile unit has interference, fading, or receives a stronger signal from another base station during the call, the mobile unit dynamically switches to a better channel based on the information contained within its history table . In a wireless local loop communication system, the distance between a radio access node and a fixed access unit is much greater than the range of operation of a wireless business system. A radio access node and a fixed access unit can be at a distance of up to 3000 meters whereas in a wireless business system, the radio access node and fixed access units are usually at a maximum of 300 meters The local channel condition can be quite different for a fixed access unit in these two systems due to the interference and blocking problems that are presented to the fixed part of the radio. A channel detected by the fixed access unit, a good channel may turn out to be a bad channel for a fixed part of the radio. A dynamic channel allocation system can not make the difference in channel quality and therefore will not effectively solve the problems associated with internal interference and blocking. As a result of this problem, the capacity of the cellular system deteriorates dramatically as traffic rises. Accordingly, there is a need for a system planning method that will effectively solve the problems associated with internal interference and blocking in a wireless local loop. SUMMARY OF THE INVENTION The present invention solves the problems associated with internal interference and blocking by providing a method of operating systems for wireless local loop communication systems. The invention features a communication method in a wireless local loop system comprising the steps of providing a set of fixed radio parts for radio communication with several fixed access units. The system then receives several graduated radio frequencies divided into several synchronized time segments. In the invention, a fixed part of activated radio and a fixed activated access unit are used for radiocommunication purposes in an assigned time segment in a selected radio frequency. In order to reduce internal interference and blocking, the system can deny radio communication, either in radio transmission or in radio reception in a selected time segment in a radio channel allocated in a predetermined number of parts fixed radios surrounding the activated radio. The system can deny both radio transmission and radio reception in its selected time segments on the assigned carrier in the predetermined number of fixed radio parts that can interfere with radio communication in the allocated time segments. The predetermined number of fixed radio parts surrounding said activated radio parts may comprise the adjacent fixed radio parts. In addition, radio transmission in the second fixed part of adjacent radio and fixed radio parts from back to back may not be allowed. In the same way, in order to minimize the internal interference during the reception of a radio signal received from a fixed access unit activated, the reception of the radio in the fixed part of the adjacent radio can be prevented, the second fixed part of adjacent radius, and all other fixed radio parts. After the fixed radio part activated and the fixed access unit activated terminate the radio communication, the assigned time segment in said selectively graded radio frequency is again available for radio communication. In order to carry out radio communication, a graduated upper frequency band may be employed to transmit signals from the set of radio fixed parts to said plurality of fixed access units. Correspondingly, a lower frequency band may be used to transmit signals from said plurality of fixed access units to said set of radio fixed parts. Other embodiments of the present invention may employ one of the radio-frequency frequencies to handle a two-way communication in said activated fixed access unit and said fixed radio-activated part. Other features and advantages of the invention will be apparent from the drawings and from the more detailed description of the invention presented below. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a diagrammatic representation of a preferred embodiment of a wireless local loop communication system. Figure IA is a diagrammatic representation of a radio access node having 6 fixed radio parts. Figure IB is a diagrammatic representation of a set "of radio access nodes Figure 2 is a diagrammatic, divided presentation of a time segment that is fundamental in TDMA-type radio communication Figure 3 is a diagrammatic illustration of the radio protocol. TMDA-TDD communication that it can be used in a wireless local loop communication system. Figure 4 is a diagrammatic illustration of the TDMA-FTDD communication protocol that can be employed in a wireless local loop communication system. Figure 5 is a diagrammatic illustration of the TDMA-FTDD communication protocol that can be employed in a wireless local loop communication system. DETAILED DESCRIPTION OF THE INVENTION The present invention presents a novel method of system operation in a wireless local loop communication system that will maintain internal radio interference and blocking at acceptable nominal levels. This method offers a much higher quality as well as greater flexibility and capacity in wireless local loop networks thus eliminating the problems associated with the prior art. The present invention offers a method of operating multi-channel wireless local loop communication systemsTherefore, it is important to have a basic understanding of how wireless local loop communication systems work. A wireless local loop communication system may vary from location to location, depending on the needs of the system. For example, a wireless local loop communication system in a rural environment is different from the systems used in an urban area with high population density. The present invention offers a method of operation for wireless local loop communication systems that allows multiple users to access the system while maintaining levels of internal interference and blocking sufficiently low so as not to affect radio communication. A person with certain knowledge in the field of radio communications, will recognize that the presented method can be adapted to many wireless networks thus increasing the quality of these systems so well. In Figure 1, the basic design of a wireless local loop communication system 10 is illustrated which could be used to carry out radio communication with several users. As illustrated, a radio access node ("RAN") 12, which may be positioned in a tower 14 above the ground, is connected to a RAN 16 control camera. The RAN 12 is responsible for the transmission and reception of radio signals from any communication device that can be connected to the wireless local loop communication system 10, using one of several standardized communication protocols. In a wireless local loop communication system 10, radio communication is carried out between the RAN 12 and a plurality of fixed access units 18 connected to a home or business. The plurality of fixed access units 18 can be connected to several communication devices, including, but not limited to, a telephone 20, a modem 22, a fax machine or any other communication device that can carry out a communication. One skilled in the art will recognize that portable telephones can also carry out radio communication with the RAN 12 and the reference to fixed access units 18 should be considered as encompassing portable telephones and all other types of units adapted for radio communication. The RAN 12 comprises a plurality of fixed radio parts 24, 26, 28, 30, 32 and 34 which are responsible for the transmission and reception of the radio signals used by the various communication devices connected to the loop communication system. wireless local. The plurality of fixed parts of radius 24, 26, 28, 30, 32 and 34 are arranged in a geometric set in such a way that they encompass 360 degrees of rotation in a horizontal plane. As illustrated in Figure IA, a set of 6 fixed parts of radius 24, 26, 28, 30, 32 and 34 is used to create the RAN 12. A set of fixed radio parts may consist of 12, 12 and 18 or more fixed radio parts and the disclosure of 6 is only by reference and is in no way a limitation. In accordance with what is described in FIG. IB, several RANs 12 may be used to create a wider coverage area. In order to allow users of wireless local loop communication system 10 to communicate with the public, the RAN control camera 16 is connected to a public switched public network scepter 36. The public switched telephone network center 36 it is connected to a public switched telephone network (PSTN) 378 and allows users of the wireless local loop system 10 to communicate with any user connected to public telephone networks. The RAN control chamber 16 is usually located near RAN 12 and is responsible for controlling the transmission and reception of radio signals between the RAN 12 and the plurality of fixed access units 18. The RAN 16 control camera is also responsible for controlling communication between a user in the wireless local loop communication system 10 and the public switched telephone network 38. In order to carry a radio communication between the various fixed radio parts 24, 26, 28, 30, 32 and 34 and the plurality of fixed access units 18, a standard digital communication protocol must be chosen. In preferred embodiments of the present invention, the novel communication method will operate in systems employing time division multiple access ("TDMA") as the standard communication protocol. TDMA is a well-known access technology that allows multiple users to occupy the same channel through the use of time division. The TDMA format used by the United States of America is the IS-54 standard and is known as the North American dual mode cellular format. In the United States of America, the Federal Communications Commission has assigned a radio frequency block of 1850-1990 MHz known as the PCS band. The higher frequency band is located in a communication range of 1930-1990 MHz and the lowest frequency band is within a range of 1850-1910 MHz for cellular digital communication. The European standard for digital wireless telephony using the TDMA format is commonly known as the Digital European Cordless Telecommunications ("DECT") standard (Digital European Wireless Telecommunications Standard). The communication method of the present invention advantageously employs the TDMA communication protocol as illustrated in Figure 3, TDMA divides a carrier 40 into a predefined repeating sequence of small time segments 42. Figure 2 illustrates a time segment typical 42. each time system 42 provides a communication device with the ability to send or receive a certain number of data bits 480 in commonly used formats. In a carrier 40 per time segment 42. since a conversation including a transmission and a reception can employ only two time segments 42, a single carrier frequency 40 can carry out several calls simultaneously. In accordance with what is illustrated in FIG. 2, the time slots 42 are routinely divided into smaller time slots that can have small portions of data that can be used as for example, for protection spaces 44, synchronization field 46, signaling field 48, data field 50, revision field 50, revision field CRC 52 and slip interference detection field 54. The precise function of each of these smaller time segments is not important for the understanding of the system channel planning method and are beyond the scope of the present invention. A TDMA method that can be employed for multiple access wireless communication is TDMA-time Duplex Division ("TDD") (TDMA - Time Division Duplex) and is illustrated in graphic form in Figure 3, which illustrates a table 43 that includes a plurality of time slots 42. the TDMA-TDD format allows a selected fixed radio part 24, 26, 28, 30, 32 or 34 to transmit to an activated fixed access unit 18 in the first plurality of time segments 43a and receiving a radio signal from the fixed access unit activated 18 in a second plurality of time segment 43b. This form of communication protocol allows a wireless local loop system to perform duplex communication, insofar as it allows simultaneous communication in opposite directions on the same carrier frequency without any noticeable time delay. In Figure 3, a carrier frequency 40 is illustrated using the TDMA / TDD communication protocol with 24 time segments 42 employed for radio communication in Table 43. In preferred embodiments of the invention, each frame can last 10 milliseconds and allow each of the 24 time segments 42 transfers or receives up to 480 bits of information. One skilled in the art will recognize that many variations can be carried out in relation to the existing installation to carry out a wireless communication. By way of example, 24 time segments 42 could be used to form a 5 millisecond frame, which allows each time segment to transfer or receive up to 240 bits of information. Another example of carrying out a radio communication in the TDMA format is presented in Figure 4, where an example TDMA - Frequency Division Duplex ("FDD") (Frequency Division Duplex) is illustrated. In TDMA-FDD, two carriers 40, 45 are used to perform radio communication between a fixed part of selected radius 24, 26, 28, 30, 32 or 34 and an activated fixed access unit 18. In preferred embodiments of the invention, a upper frequency block channel is used to transmit signals from the selected radio fixed part 24, 26, 28, 30, 32 or 34 and the fixed access unit activated 18, and a lower frequency block channel can be used to receive radio signals transmitted from the fixed access unit activated 18. This form of communication protocol is an example of full duplex communication, and allows wireless local loop systems 10 to transmit data in both directions simultaneously and continuously. A third example of the TDMA communication protocol known as TDMA - Frequency-Time Duplex Division ("FTDD") (Frequency-Time Division Duplex) is illustrated in Figure 5. In this form of radio communication, the first carrier frequency 40 located in the upper frequency block in preferred embodiments, it employs the first 20 time segments 43a of a frame to transmit radio signals from the selected fixed part of radius 24, 26, 28, 30, 32 or 34 and the unit of fixed access activated 18. The second carrier frequency 45, located in the lower frequency block in preferred modes, allows the activated fixed access unit 18 to transmit radio signals to the selected fixed radio part 24, 26, 28, 30, 24 or 34 in the last 12 time segments 43b of Table 43. This form of communication protocol is another example of full-duplex communication and allows the trans-local wireless loop system mita radio signals in both directions with a certain deviation of time segment. In preferred embodiments of the present invention, the method for controlling radio communication in a wireless local loop communication system comprises the steps of providing a plurality of fixed access units 18 in radio communication with a set of radio fixed parts 24, 26, 28, 30, 32 or 34; employ a plurality of radio channels 40 divided into a predetermined number of synchronized time slots 42; performing a radio communication, such as radio transmission or radio reception between an activated fixed access unit 18 and a fixed radio part activated as for example the fixed radio part 30 only during a selected time segment 42 in an assigned radio channel 40; and denying a radio communication on said assigned radio channel 40 during said selected time segment 42 at a controlled number of the fixed radio parts 24, 26, 28, 32 or 34 surrounding said fixed part of radio activated 30 during its communication with said fixed access unit activated 18. In the invention, the controlled number of fixed radio parts 24, 26, 28, 30, 32 and 34 where the radio communication is denied during said selected time segment 42 may include the number of fixed radio parts 24, 26, 28, 32, and 34 that can create radio interference with the radio communication between said activated radio part 30 and said activated fixed access unit 18. The method of the present invention offers a multi-channel planning for wireless local loop communication systems 10 denying radio transmission in an assigned radio channel 40 during a selected time segment 42 in a controlled number of fixed parts radios 24, 26, 28, 30, 32 and 34 surrounding one or more of the activated radio fixed parts 524, 26, 28, 30, 32 and 34. In the same way, the invention offers a method for denying the radio reception in an assigned radio channel 40 during another selected time segment 42 in a controlled number of fixed radio parts 24, 26, 28, 30, 32 or 34 surrounding one or more of the radio active fixed parts 24, 26, 28, 30, 32 and 34. With reference to Figure IA and considering that the fixed part of radio 30 has been activated for radio communication, the controlled number of radio fixed parts 24, 26, 28, 32 and 34 surrounding said fixed part of activated radius 30 may comprise the adjacent fixed radio parts 28, 32; the second adjacent fixed radio parts 26, 34; and the fixed radio parts from back to back 24. Another preferred embodiment of the present invention offers a method for carrying out radio communication in a wireless local loop system 10 by providing a set of radio fixed parts 24, 26, 28, 30, 32 and 34 for radio communication with a plurality of fixed access units 18. A plurality of radio-frequency frequencies 40 are divided into a plurality of synchronized time slots 42 for carrying out radio communication. A fixed active radio part 30 and an activated fixed access unit 18 then employ an allocated pair of time slots 42 at a selected frequency of graded radius 40 to transfer and receive information. During radio communication which may be either transmission or reception, between the fixed part of radio activated 30 and the fixed access unit activated 18, the radio transmission in the assigned pair of time segments 42 on the radio frequency graduated selected 40 is not allowed in the adjacent radio fixed parts 28, 32. The radio communication method may also not allow radio transmission in the allocated pair of time segments 42 at the selected radio frequency frequencies 40 in the second fixed parts adjacent radio stations 26, 34 during radio transmission between the fixed part of the activated radio 30 and the fixed access unit activated 18. Furthermore, the radio transmission may not be allowed in the assigned pair of time segment 42 on a frequency selected radio signal 40 in fixed parts of radio from back to back 24 during radio transmission between the fixed part of radio activated 30 and the access unit f Ija activated 18. Accordingly, during a radio transmission between a fixed part of activated radio 30 and a fixed access unit activated 18, the method may not allow a radio transmission in one or all of the fixed radio parts 24, 26, 28, 32, 34 surrounding a fixed part of activated radio 30. In addition to not allowing a radio transmission in the segment of allocated time 42, the system channel planning method may also not allow radio reception on one or all of the fixed radio parts 24, 26, 28, 32, 34 surrounding the fixed part of activated radio 30. This means that the radio reception in adjacent fixed radio parts 28, 32, in the second fixed radio adjacent parts 26, 34, and in fixed parts of radio from back to back 24 may not be allowed during the reception of a radio signal from the fixed part of the activated radio 18. The present invention provides a method for carrying out radio communication in a wireless local loop, comprising the steps of providing a set of radio fixed parts 24, 26, 28, 30 , 32 and 34 in radiocomu With a plurality of fixed access units 18, divide a plurality of radio channels 40 into a predetermined number of synchronized time slots 42 to carry out a radio communication between an activated fixed access unit 30 and a fixed part of activated radio 18, denying a radio transmission in a selected time segment 42 in a radio channel by allocating 40 in a predetermined number of fixed radio parts 24, 26, 28, 32 or 34 that can interfere with the fixed part 30 of radio activated during the transmission of a radio signal to the fixed access unit activated 18; and denying a radio reception in said selected time slot 42 in the assigned radio channel 40 to the predetermined number of fixed radio parts 24, 26, 28, 32 or 34 that surround the fixed part of radio activated 30 while receiving a radio signal from the fixed access unit activated. The predetermined number of fixed radio parts 24, 26, 28, 32 or 34 that can not transmit or receive can comprise more adjacent fixed radio parts 28, 32 the second fixed radio adjacent parts 26, 34 and the fixed part of radio from back to back 24. The method can also be employed by using one of the channels of a higher frequency band of radio channels to send radio signals from the fixed part of the activated radio 30 to the activated fixed access unit 18. A channel from the lower frequency band can then be used to receive radio signals from the activated fixed access unit 18. Obviously a radio channel 42 can be used to carry out a radio communication between the fixed part of the radio. activated radio 30 and the fixed access unit activated 18. The present invention includes a wireless local loop communication system 10 comprising a plurality of fixed access units 18 in radio communication with a set of fixed radio parts 24, 26, 28, 30, 32 and 34. The system employs a plurality of radio channels 40 divided into a predetermined number of synchronized time slots 42. A control unit 16 is it is connected to said set of radio fixed parts 24, 26, 28, 32 and 34 to negate radio transmission in an assigned radio channel 40 during a selected time segment 42 in a controlled number of fixed radio parts 24, 26 , 28, 32 or 34 surrounding a fixed part of activated radio 30 during the transmission of a radio signal to an activated fixed access unit 18. The wireless local loop communication system 10 may also employ the control unit 10 for denying the radio reception in said assigned radio channel 40 during selected time segment 42 in a controlled number of radio fixed parts 224, 26, 28, 32 and 34 surrounding said fixed radio-activated part 30 during the transmission of a radio signal to said fixed access unit activated 18. The controlled number of fixed radio parts surrounding said activated radio part 30 may comprise the adjacent fixed radio parts 28, 32, the second fixed radio adjacent parts 26, 34 and the fixed part of radio from back to back 24. Although several preferred embodiments of this invention were presented, one skilled in the art will recognize that the methods presented can be employed in numerous types of communication systems. It will be understood that a wide range of changes and modifications to the embodiments described above will be apparent to those skilled in the art and contemplated within the invention. Accordingly, it is contemplated that the foregoing detailed description have only an illustrative and non-limiting value and that they are the following claims including all of their equivalents that define the true spirit and scope of this invention.