MXPA00005043A - Traffic channel assignment in a cellular telephone system using an uplink interference driven frequency packing method - Google Patents

Abstract

Each base station (14) in a cellular telephone system includes a signal strength measurement device (30, 32) operable to tune to and make signal strength measurements on not only the frequencies allocated to other cells, but also on its own allocated frequencies. Measurements (104) are made by the device on those of its own frequencies having idle traffic channels to obtain an indication of injected uplink interference. An interference penalty is then assessed (114) against the measured uplink interference for those frequencies having more than a threshold number (110) of idle traffic channels. The adjusted measurements for the frequencies allocated to the cell are then sorted (118) in relative order of idle traffic channel (adjusted) measured uplink interference from a least (adjusted) interfered frequency to a most (adjusted) interfered frequency. An idle traffic channel is then selected for assignment (120) at either call set-up or hand-off from the least (adjusted) interfered frequency.

Description

ALLOCATION OF TRAFFIC CHANNEL IN A TELEPHONE SYSTEM CELLULAR USING A FREQUENCY INTEGRATION METHOD DRIVEN BY ASCENDING LINK INTERFERENCE BACKGROUND OF THE INVENTION TECHNICAL FIELD OF THE INVENTION The present invention relates to cellular telephone systems and, particularly, to an apparatus method for selecting and assigning a traffic channel during the establishment of calls and call transfers by means of the evaluation of measurements. strength of uplink signal combined with frequency integration analysis. DESCRIPTION OF THE RELATED TECHNIQUE Cellular telephone systems divide a large service area into numerous smaller discrete geographical areas that are known as "cells", each of which is typically located within a size range of approximately half of one kilometer to approximately 20 kilometers in diameter. Each cell is contiguous with several adjacent cells to provide continuous coverage throughout the service area. A base station that includes several transceivers capable of operating independently at different radio frequencies is provided for each of the cells. Through the transceivers, the base stations carry out simultaneous communications with several mobile stations operating within the area of the associated cell. The base stations also communicate via data link (and voice trunks) with a central control station, which is often referred to as a mobile switching center, which functions to selectively connect telephone calls to mobile stations and from the mobile stations through the base stations and, in general, control the operation of the system. Each cell is assigned the use of a predetermined set of frequencies, where each frequency comprises a physical channel that supports several logical channels (ie, time segments). The availability of several frequencies per cell, with several logical channels per frequency allows stations to simultaneously handle many telephone conversations with many mobile stations. The frequencies assigned to a cell are preferably spaced apart in the frequency spectrum of the cellular band. This serves to minimize the cases of interference from adjacent channels. Due to the fact that only a limited number of frequencies are available in the cellular band, the assignment of the same frequencies is repeated (i.e., reused) in other cells at a location distant from large service areas with many cells. Non-adjacent cells, however, receive the same frequency. In addition, the power levels of the signal transmissions at a given frequency are limited. The above precautions serve to minimize the probability of co-channel interference caused by the reuse of the same frequency in a distant cell. Despite the precautions taken by the service providers, it is known that interference occurs between adjacent and co-channel channels. This interference frequently adversely affects the operation of the system by, for example, the degradation of voice or data in the traffic channels or by interference with the transmission and reception of control signals in the control channels. The mobile switching center functions to dynamically allocate the available traffic channels in any cell among several mobile stations located within the cell area that wants communications. Regarding this aspect, the traffic channels comprise time segments in frequencies formatted by time division multiple access (TDMA) that are assigned to the cell. Commands that assign for mobile station the use of a certain digital traffic channel assigned to a given cell are transmitted from the mobile switching center to the base station for this cell. The commands are then relieved by the base station towards the mobile station it is a matter in one of the channels to direct the mobile station selection of the assigned traffic channel to handle the call. The assignment by the mobile switching center of a particular digital traffic channel in a cell to a particular mobile station to carry a cellular communication (i.e., a call) occurs primarily in two cases. The first case is for the establishment of a call when the subscriber activates the mobile station to initiate a call and the system selects the traffic channel assignment to make said new call. The second case is a call transfer when the subscriber, while making a call, moves from one cell in a service area to another cell, and the system selects for allocation the traffic channel in this new cell that will continue to handle the call in progress. In any case, it is important that the traffic channel selected for assignment at the time of establishing or transferring a call has the highest possible quality. Conventionally, the selection and assignment by the system of a traffic channel to carry a call is made by randomly choosing a logical channel from the available (inactive) digital traffic channels assigned to the cell that is currently serving. to the mobile station. Alternatively, the system maintains a record of the historical use of traffic channels for each cell (usually in the form of a FIFO queue (first inside, first; outside)), and the traffic channel selected to carry the call is the channel assigned to this cell that has not been assigned for mobile station call use in the longest period of time. While each of these selection methods is successful in assigning a traffic channel in a cell to a mobile station to carry the call, the selection does not take into account whether the traffic channel is the highest quality channel (ie, least interfered) available to take the call. The prior art selection methods fail to take into account precautions in terms of minimizing the interference that may arise subsequently after the allocation of the traffic channel, and minimizing the number of frequencies in use simultaneously. In many cases, there may be significant interference (often involving adjacent channel interference or perhaps more often co-channel interference) in the randomly selected traffic channel or in queue or unacceptable interference may result after the assignment due to an inefficient simultaneous use of frequencies, and another of the inactive traffic channels available in the cell could have been a more appropriate allocation selection for use to carry the call. There is therefore a need for an improved method for assigning traffic channels to carry a call in response to either the establishment of a call or the transfer of a call. This method must take into account not only whether the traffic channel is the best quality (ie, least interfered with) channel available to carry the call, but also whether the required minimum number of frequencies is being used to handle the needs of traffic. COMPENDIUM OF THE INVENTION Signal strength measurements are made by a channel force measurement device in each cell base station at the frequencies assigned to the cell having inactive traffic channels. From these measurements, the uplink interference injected (which comprises either adjacent channel interference, co-channel interference or other interference) at the frequencies for each of the inactive traffic channels is determined and reported to the mobile switching center. The reported uplink interference measurements are then adjusted through a predetermined interference penalty if the frequency assigned to the cell currently includes more than a predetermined number of inactive traffic channels. The adjusted measurements for all frequencies are then sorted in relative order of uplink interference measured (adjusted) from inactive traffic channel from a frequency less interfered (adjusted) to a frequency more interfered (adjusted). The classified list is then used by the system to select for a base station a traffic channel from the least interfered (adjusted) frequency for assignment either to establish a call or to transfer a call. BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding of the method and apparatus of the present invention can be obtained by reference to the following Detailed Description when taken in conjunction with the accompanying Drawings where: Figure 1 is an exemplary cell diagram illustrating a system of frequency reuse cellular telephony where the present invention is implemented; Figure 2 is a block diagram meaning of a base station in accordance with the present invention for use in the frequency reuse cellular telephone system of Figure 1; Figures 3A and 3B are flow charts illustrating alternative methods of operation for the channel selection process of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS There are several radio frequencies in the cellular band available to providers of cellular telephone systems for use to communicate with mobile stations. These radio frequencies support both traffic channels and control channels. Traffic channels are used to carry out voice or data telephone conversations. The channels of. control are used to carry control signals of system operation (commands). Such control signals include paging signals, paging response signals, location registration signals, traffic channel assignments, maintenance instructions, as well as instructions for selecting or reselecting cells. A cellular service area can encompass a large geographic area and in many cases there is a need for a large number of cells that frequently exceeds in number the number of cells provided by dividing the available radio frequencies to handle the use expected by subscribers. Therefore, in order to provide sufficient call handling capacity in the service area, the cells are grouped into groups of cells and the radio frequencies in the cell band are reused in each of the groups. Reference is now made to Figure 1 for an illustration of an example of the concept of frequency reuse commonly used in cellular systems. An arbitrary geographical area (hereinafter referred to as "service area") is divided into several contiguous cells 10 represented schematically by hexagons.The cells 10 are then grouped into groups 12 (marked with darker lines to facilitate recognition), which in the present example comprises seven cells 10 (1) -10 (7) in each group.For this example we consider that there are a total of 28 fn frequencies (where n = 28) available in the cellular band.It will obviously be understood that each frequency it comprises in fact a pair of uplink and downlink frequencies.The frequencies f1-f28 are equally divided between the cells 10 (1) -10 (7) to provide 4 frequencies per cell., each of the cells 10 (1) in the service area is assigned frequencies fl, f8, fl5 and f22 to carry traffic and control channels. Similar assignments are made for each of the remaining cells 10, with the frequencies being reused in each of the included groups 12. The complete assignment of the fl-f28 frequencies to the 10 (1) -10 (7) cells in each group 12 in accordance with this example of cellular frequency reuse is illustrated in detail in figure 1 as a relation to group 12 (1). It will be observed that in this frequency reuse scheme, in no case does it have adjacent cells to which the use of the same frequency is assigned. The reuse of an identical frequency in the service area requires at least a separation of at least one cell 10 together with an emission power regulation for each cell to limit radio propagation substantially within the area of the cell. Furthermore, it will be noted that in no case does a cell 10 employ adjacent frequencies in the cellular band. Between adjacent frequencies there must exist at least one cell 10. By arranging the cell 10 in groups 12 as shown in the figure, the regulation of the communication diffusion power within the cell and by assigning frequencies in the manner described above and illustrated in the figure, the likelihood of interference is minimized while providing effective and efficient cellular communication services at a very broad service area simultaneously. Despite the precautions taken to avoid interference, it is known that interference occurs in cellular systems of the type described above. One aspect of this interference arises from communications that occur in the cells of other groups on the same frequency (ie, co-channel interference). To understand this phenomenon, consider the existence of concurrent voice communications that use a frequency flO (and perhaps individual time segments there) in each of the cells 10 (3) in each of the groups 12 (2), 12 ( 3) and 12 (4) as shown in Figure 1. Despite any imposed diffusion power limitation, a certain amount of radio frequency energy from these voice communications propagate beyond the respective limits of the cells and it is injected as interference in frequency flO in cell 10 (3) of group 12 (1). Another aspect of this injected interference arises from communications that occur in other cells at adjacent frequencies (ie, interference from adjacent channels). To understand this phenomenon, consider the existence of concurrent voice communications at frequency fd in cells 10 (1) and frequency f9 in cells 10 (2), and perhaps individual time segments there, group 12 (1) as shown in Figure 1. In spite of any regulation on diffusion power and the presence of protection bands around each frequency, inappropriate transmitter broadcasts can be injected around a frequency (eg, fd) as interference in the adjacent frequency as interference in the adjacent frequency f9. It will be recognized that adjacent channel interference is not as common as co-channel interference in stable and well-regulated communication systems. Since this injected interference can negatively affect cellular voice communications at a given frequency, it would be unwise for the system to act during certain times of high interference by assigning this given frequency (or channel) to a mobile station either in the case of establishment of a call or of the transfer of a call to carry a cellular voice communication. Unfortunately, the random or tail channel selection methods of the prior art do not obtain injected interference information or consider such interference injected and its adverse effects on the selection and assignment of voice channels (including a time segment within the frequency) either during the establishment of a call or during the transfer of a call. It would be a great advantage for the operation of the system if voice channel quality measurements and evaluations could be made before the selection and allocation of system voice channels. Concerns regarding co-channel interference extend to the level of the time segments within each frequency. It is recognized that in moments of moderate light load, all frequencies (or all time segments there) are not required for assignment to voice communications management. Situations arise in which all the time segments associated with a single frequency are not used. Some injected co-channel interference arises from this use. At the same time, none of the various time segments on another frequency can be used. No injected co-channel interference arises from this use. When a traffic channel assignment is made subsequently, the random or tail channel selection methods of the prior art do not allow to obtain knowledge of the use of time segment or to consider such use among the frequencies assigned in a cell before selecting and assigning a voice channel (comprising a time segment within the frequency) during either the establishment of a call or its transfer. It could be a great advantage for the operation of the system if efforts were made to minimize the number of frequencies used actively to carry out communications before in relation to the selection and allocation of system voice channel. Each of the cells 10 in a cellular system such as the system illustrated in Figure 1 includes at least one base station (BS) 14 configured to facilitate radio frequency communications with mobile stations 16 that move in the service area. The base stations 14 are illustrated as being located in the center of each of the cells 10 or close to said center. However, depending on geographical factors or other known factors, the base stations 14 may be located on the periphery of each of the cells 10 or close to said periphery or may be located otherwise away from the centers of said cells. 10. In cases of this type, the base stations 14 can emit and communicate with mobile stations 16 located within the cells 10 using directional antennas instead of using omnidirectional antennas. The base stations 14 are connected through communication links (illustrated schematically by an arrow 17) with at least one mobile switching center (MSC) 18 operating to control the operation of the system to provide cellular communications with the stations 14. Reference is again made to Figure 2 where a simplified block diagram of a base station 14 employed in the system of Figure 1 according to the present invention is shown. The base station 14 includes several transceivers (Tx / Rx) 20 (1) to 20 (N), where N is the number of frequencies assigned to the cell 10 receiving service from the base station. In the exemplary system illustrated in Figure 1, N = 4, where 7 cells 10 are included in each group 12 and a total of 28 radio frequencies available in the cell band. The transceivers 20 have a configuration known in the art that includes a transmitter and a receiver tuned to operate on one of the frequencies assigned to the base station 14 for its traffic and / or control channels. Each assigned frequency provides a plurality of digital TDMA channels for use by the mobile station. The base station 14 also includes a signal force measuring device 22 which is employed in a manner known in the art during the transfer to measure the communication signal strength at the voice frequencies assigned to other cells and used by other cells. cells In accordance with the present invention, the operation of 1 signal strength measuring device 22 of each base station 14 is controlled in an additional mode of operation through received mobile switching center commands and / or station programming. of base to measure the strength of the communication signal in each of the frequencies that support inactive traffic channels that are assigned to the base station. These measurements are made at selected times or are made periodically in accordance with the system specifications. The results of the measurements provide an indication of the amount of uplink interference injected caused by communications on the same channel or adjacent channel occurring simultaneously within the system, or caused by another source of interference. Measurements of inactive traffic channel signal strengths including uplink interference, measured (either based on frequency or based on time segment) are reported by means of signal strength measurement devices 22 of the base station 14 towards mobile switching center 18 (perhaps together with the signal strength measurements of transfer traffic channel that are made in the frequencies / channels that are assigned to other cells) and are considered in relation to the selection process and assignment of a voice channel either to establish a call or for transfer. Alternatively, a processor 24 within the base station 14 may receive the measured uplink interference (either on a frequency basis or on a time segment basis) to process to select and assign a voice channel either to establish call or transfer call. In one embodiment of the present invention, the signal strength measuring device 22 comprises a location verification module (LVM) 30 that includes a receiver and a frequency synthesizer to selectively tune to one of the frequencies available in the cellular band. Since each of the frequencies assigned to a cell 12 is subdivided into several time segments comprising the traffic channels, the location verification module 30 also includes a circuit (not explicitly illustrated) to synchronize the operation of the module with the TDMA communication protocol implemented by the system in such a way that measurements of signal strength in a selected frequency can be made during each of the various time segments included there . This would include not only the frequencies / time segments assigned to other cells and used by other cells, but also the frequencies / time segments allocated to the cell receiving service from the base station 14 and used by the cell receiving service from the base station 14. The signal strength measurements made by the location verification module 30 are then filtered by an infinite impulse response filter (IIRF) 34 before subsequent processing in accordance with the present invention. The filtering removes the rapid changes in the measured levels of interference to provide a stable estimate of output and for subsequent processing. As for the implementation of the present invention, the location verification module 30 makes measurements and reports measurements in terms of frequencies / time segments associated with inactive traffic channels for the purpose of providing uplink interference measurement data. In another embodiment of the present invention, the signal strength measuring device 22 comprises an inactive channel supervision (ICS) 32 functionality associated with each transceiver 20. The inactive channel monitoring functionality 32 advantageously employs the portion of Transceiver 20 receiver for making the uplink signal strength measurements. This inactive channel monitoring functionality 32 may include a circuit (not explicitly illustrated) for synchronizing a measurement operation to the TDMA communication protocol implemented by the system such that measurements of signal strength at a selected frequency may be made during each one of the several time segments included. The selected frequencies in which measurements are made comprise the frequencies / time segments assigned to the cell receiving service from the base station 14 and used by the cell receiving service by the base station 14. Regarding the implementation of In the present invention, the location verification module 30 makes measurements and reports measurements on frequencies / time segments associated with inactive traffic channels for the purpose of providing uplink interference measurement data. The signal strength measurements made by the inactive channel monitoring functionality 32 are then filtered through an infinite impulse response filter (IIRF) 34 prior to subsequent processing in accordance with the present invention. The filtering removes the rapid changes in the measured levels of interference to provide a stable estimate for subsequent production and processing. In one embodiment of the present invention, the base stations report signal strength measurements on an idle time segment base to the processor 24 or to the mobile switching center for processing. For this embodiment, the processing means comprises either the processor 24 in the mobile switching center or the mobile switching center can make specific channel-specific intelligent assignments for time segment in terms of minimizing the interference problems ( example, selecting a less interfered time segment within a selected frequency). In another embodiment, the base stations process the signal strength measurements made on an inactive time segment basis to obtain an interference measurement for the frequency (i.e., the carrier). It is this carrier-based interference measurement that is reported to the processing means comprising either the processor 24 or the mobile switching center. For this modality, the processor 24 or the mobile switching center does not proceed interference implementation per time segment from which an intelligent allocation selection can be made. Instead, the processor 24 or the mobile switching center makes the decision as to which time slot channel to allocate based on a random selection among the inactive time segments in the least interfered carrier. More information on the processes implemented in accordance with the present invention is provided herein. Reference is now made to Fig. 3A where a flow diagram showing a form of operation of the channel selection process of the present invention is illustrated. In step 100, at a designated time point, the mobile switching center of the cellular telephone system generates a message that instructs some of the base stations to make inactive traffic channel signal strength measurements. This command instruction message is sent to the base stations designated in step 102. At each of the receiving base stations, the command message is implemented in step 104 by configuring the signal strength measuring device of the base station to tune it to the assigned frequencies of the base station itself and make signal strength measurements (i.e., uplink interference measurements) at frequencies with inactive traffic channels that have been assigned to the cell receiving service from the particular measurement base station. Where possible, these measurements are carried out on an inactive time segment basis. It should be understood that this is a mode of operation in addition to the conventional mode of operation for making measurements on neighboring cell voice channels in response to a transfer request and the determination of a target cell. The results of the uplink interference measurements (signal strength) at the frequencies with inactive traffic channels reporting through the signal strength measuring device returned to the mobile switching center in step 106. Again, alternatively , the measurements are reported to the processor 24 of the base station. This report can also be made upon receipt of a request from the mobile switching center. This report comprises either the measurements on an inactive time segment basis, or the accumulated measurement for a frequency (carrier). If the report is specific for time segment, appropriate accumulation processing is carried out in the processing device comprising either the base station processor or the mobile switching center to carry out an interference calculation per frequency. A determination is made in step 110 regarding the load on each frequency having an uplink interference measurement reported in step 106. This load determination evaluates, in general, the number of inactive time segments within each measured frequency. If the number of inactive time segments exceeds a predetermined threshold number (see, path 112), an interference penalty against the uplink interference measured for this frequency / carrier is evaluated (step 114). If the threshold number is not exceeded (see, trajectory 116), no penalty is applied. Even if not specifically illustrated, it is understood that the process of steps 110 and 114 is carried out, as necessary, in relation to each of the frequencies having a reported uplink interference measurement step 106. After the adjustment (if any) applied in step 114 to the reported uplink interference measurements, the (adjusted) measurements in step 118 are processed to generate a classified list of measured frequencies that have inactive traffic channels that are candidates for selection and assignment either to establish a call or for transfer. The generated list is classified by the measurements reported in the relative order of the measured (adjusted) uplink interference of the traffic channel (for example, from the least interfered frequency (adjusted) to the most interfered (adjusted) frequency). In a case of traffic channel capture (step 120), an inactive channel of the traffic channels within the frequency minus interfered (adjusted) in the reclassified list is randomly selected and assigned either for call setup or for transfer. Alternatively, if an individual time segment interference information is available, the least interfered time segment is selected within the frequency minus interfered (adjusted). Referring now to Figure 3B, there is shown a flow diagram illustrating an alternative method of operation in accordance with the present invention where a loop 122 and step 104 refer to the programming of the base station to periodically measure the force of the signal at frequencies having inactive voice channels that have been assigned to the cell receiving service from a particular measurement base station. If possible, these measurements are made on a per-segment-inactive basis. In step 124 in the loop 122, base station programming tests the appearance of a report event. By this we understand some cellular system event in response to which the measurements must be reported to the mobile switching center or the base station processor. An event of this type comprises receiving a command from the mobile switching center that specifies the transmission of the most recent measurements. Another event of this type comprises the reception of a command from the mobile switching center that instructs the signal force measuring device to make measurement in the traffic channels of other neighboring cells to prepare the transfer and selection of a signal. white cell. In this case, the measurements that refer to the traffic channels themselves are added to the message report about the elaborated measurements of the traffic channels for the neighboring cells. Another event of this type comprises the existence of time out, thus making a periodic report of the signal strength measurement information of traffic channel. In addition, the report event comprises a change in measured interference greater than a certain hysteresis value. Once the report event occurs, the measurements are reported in step 106 to the mobile switching center. Again, alternatively, this measurement report can be made to the processor 24 of the base station. The report comprises either the measurements on an inactive time segment basis, or the accumulated measurement for a frequency (carrier). If the report is specific for time segment, appropriate accumulation processing is carried out in the processor of the base station or mobile switching center to perform a frequency interference calculation. Preferably, no report is made 106 if the most recent previous report was sent within a predetermined time period. A determination is then made in step 110 as to the relative load on each frequency having an uplink interference measurement reported in step 106. This load determination evaluates, in general, the number of time segments inactive within each frequency. If the number of inactive time segments exceeds a predetermined threshold number (see path 112), an interference penalty against the uplink interference measured for this frequency is evaluated (step 114). If the threshold number is exceeded (see, path 116), no penalty is applied. Although not specifically illustrated, it is understood that the process of steps 110 to 114 is carried out as required, with respect to each of the frequencies having a measured measurement step 106 of uplink interference. After the adjustment (if any) applied in step 114 to the reported upstream interference measurements, the (adjusted) measurements in step 118 are processed to generate a classified list of frequencies having inactive traffic channels that are candidates for selection and allocation and either to establish a call or to transfer. The list generated is classified from the measurements reported in order of relative uplink interference (adjusted) inactive traffic channel measure (for example from the least interfered frequency (adjusted) to the most interfered frequency (adjusted)). In a traffic channel tap case (step 120), an inactive channel of the traffic channels within the frequency minus interfered (adjusted) in the reclassified list is randomly selected and assigned either to establish a call or for transfer. Alternatively, if an individual time segment interference information is available, the least interfered time segment within the least interfered (adjusted) frequency is selected. The particular penalty applied in step 114 against classified and previously made uplink interference measurements the number of inactive traffic channels exceeds the threshold may differ according to the precise number of inactive traffic channels present. For example, in a frequently implemented TDMA communication system, each frequency includes three time segments. The predetermined threshold in a situation of this type may require that two or more time segments are in relation to a given frequency before applying the penalty. Thus, if two segments of inactive time are found, the. The penalty that is applied to the measurement of uplink interference is Xdb. On the other hand, if three inactive time segments are found, the penalty applied to the uplink interference measurement is X + Ydb. A similar penalty scheme is implemented in relation to the eight time segments (resulting in seven penalty levels) associated with a Global Sistem for Mobile (GSM) communication system (Global System for Mobile). In any case, the object of applying the penalty to make the associated frequency having said large number of inactive time segments less attractive when step 120 is carried out. Conversely, in the case of frequency that has only one inactive time segment, no penalty is applied in order to continue making this inactive time segment an attractive candidate for take. As for the classified list (step 118), all frequencies assigned to a cell that has inactive time segments can be included in a single complete list. Alternatively, multiple lists may be generated in case 118 to take into account, for example, differences that may need to be considered when taking the step 120. For example, it is known that the cellular frequency band includes both a Basic band as an extended band. It is possible for classified lists to be generated through separate step 118, a list for frequencies having inactive traffic channels in the base band and a list for frequencies having inactive traffic channels in the extended band. In another example, a list can be provided only for data call, a list only for voice calls, and a list for both data calls and voice calls. At the time of the take (step 120), an appropriate traffic channel (or perhaps more than one) of the reclassified list is then evaluated in relation to the random or intelligent choice of an inactive traffic channel to establish a call or for transfer. Even when a preferred embodiment of the method and apparatus of the present invention has been illustrated in the accompanying drawings and that said embodiment has been described in the above Detailed Description, it will be understood that the invention is not limited to the embodiment presented, but may present numerous adjustments, modifications and substitutions without departing from the spirit of the invention proposed and defined in the appended claims.

Claims (30)

1. CLAIMS A cellular telephone system, comprising: a base station assigned for the use of several frequencies, each frequency includes several time segment traffic channels, comprising: a signal measurement device that can be selectively tuned to make measurements signal strength in the frequencies signaled to the link station having traffic channels of idle time segments and to obtain uplink interference measurements at the measured frequencies; and a processing device connected to receive the uplink interference measurements, the processing device operates to: apply an interference penalty against the uplink interference measurements received if the measured frequency includes more than a threshold number of channels of traffic of inactive time segments; classifying the measured frequencies or their adjusted uplink interference measurements or any interference penalty applied from at least one uplink interfered frequency to one frequency interfered with uplink; and selecting for assignment by the base station a channel for call set-up or transfer of the traffic channels of inactive time segments included within the frequency minus interfered by uplink.
2. The system according to claim 1, wherein the signal force measuring device comprises a base station location verification module.
3. The system according to claim 1, wherein the signal strength measuring device comprises a base station inactive channel monitoring functionality provided by a base station transceiver.
4. The system according to claim 1, wherein the signal force measuring device makes signal strength measurements for each inactive time segment.
5. The system according to claim 1, wherein the sorting operation of processing means classifies the measured frequencies or their adjusted uplink interference measurements or any interference penalty applied in several lists, each list is ordered from a frequency less interfered with. uplink to a more interfered frequency uplink.
6. The system according to claim 5, wherein the selecting operation of the processing device selects between one or more of the numerous lists to assign a channel to establish a call or transfer a call between the traffic channels of inactive time segments included. within the frequency less interfered with uplink contained in said list.
7. The system according to claim 1, wherein the processing device application operation applies an increasing interference penalty against the received uplink interference measurements corresponding to when an increasing number of traffic channels of inactive time segments are included within the frequency.
8. The system according to claim 1, wherein the processing device includes a mobile switching center connected to the base station.
9. A method for employing a cellular telephone system for allocating traffic channels, comprising the steps of: making signal strength measurements at frequencies assigned to a base station, wherein each frequency includes a plurality of time segment traffic channels , measurements made on these frequencies have traffic channels of inactive time segments to obtain uplink interference measurements; apply an interference penalty against uplink interference measurements made if the measured frequency includes more than a threshold number of traffic channels of inactive time segments; classify the frequencies measured by their uplink interference measurements adjusted by any interference penalty applied from a frequency less interfered with uplink to a more interfered up link frequency; and selecting for allocation by the base station a channel to establish a call or transfer of the traffic channels of inactive time segments included within the frequency minus interfered by uplink.
10. The method according to claim 9 wherein the step of making signal strength measurements comprises the step of making signal strength measurements for each inactive time segment.
11. The method according to claim 9 wherein the step of classifying comprises the step of classifying the frequencies measured by their uplink interference measurements adjusted by any interference penalty in several lists, each list ordered from a frequency less interfered with by uplink to a frequency more interfered with uplink.
12. The method according to claim 11 wherein the step of selecting comprises the step of selecting, from one or more of the various lists for assignment to establish a call or for transfer, one of the traffic channels of segments of inactive time included within the frequency less interfered with uplink contained in this list.
13. The method according to claim 9 wherein the step of applying comprises the step of applying a penalty for increasing interference against the received measurements of uplink interference corresponding to when an increasing number of traffic channels of inactive time segments they are included within the frequency.
14. The method according to claim 9 wherein the step of selecting comprises the step of randomly selecting a traffic channel of inactive time segments included within the frequency minus interfered by uplink.
15. 15. The method according to claim 9 wherein the step of selecting comprises the step of selecting a traffic channel of inactive time segments having the least interference included within the frequency minus interfered by uplink.
16. 16. A cellular telephone system having a plurality of frequencies available to carry out cellular communications, each frequency includes a plurality of time segment traffic channels, comprising: a plurality of base stations distributed in a service area , each base station is assigned to employ a subset of the various frequencies where each base station comprises: a signal strength measuring device that can be selectively tuned to make signal strength measurements at any of the various frequencies of the system; and a processing device: connected to receive a report from a given base station of measurements made by the signal strength measuring device at selected frequencies of the subset of frequencies assigned to this given base station including traffic channels inactive, the measured signal strengths indicating uplink interference; and operating to process the uplink interference signal strength measurements for the selected frequencies and selecting for allocation by the given base station an inactive traffic channel at a frequency with less possible interference from the frequencies selected as possible while employs simultaneously the smallest possible number of frequencies assigned to this given base station.
17. The system according to claim 16 wherein the signal force measuring device comprises a verification module of location.
18. The system according to claim 16 wherein the signal force measuring device comprises an inactive channel monitoring functionality provided by a base station transceiver.
19. The system according to claim 16 wherein the signal strength measuring device makes signal strength measurements for each inactive time segment.
20. The system according to claim 16 wherein the processing device operates to process and select by: the application of an interference penalty against the measurements received from uplink interference if the measured frequency includes more than a threshold number of channels traffic of inactive time segments; classify the frequencies measured by their uplink interference measurements adjusted by any interference penalty applied from a frequency less interfered with uplink to a frequency more interfered with uplink; and selecting for assignment by the base station in the establishment of a call or transfer, one of the traffic channels of inactive time segments included within the frequency minus interfered by uplink.
21. The system according to claim 20 wherein the processing device performs the sorting operation to classify the frequencies measured by its uplink interference measurements adjusted by any interference penalty applied in several lists, each list is ordered from from a frequency of lower uplink interference to a frequency of higher uplink interference.
22. The system according to claim 21 wherein the processing device carries out the selection operation to select from one or more of the lists for assignment in the establishment of a call or transfer one of the various segment traffic channels of inactive time included within the frequency with least uplink interference contained in this list.
23. The system according to claim 20 wherein the processing device performs the application operation to apply an increasing interference penalty against the received uplink interference measurements corresponding to when an increasing number of traffic channels of inactive time segments are included within the frequency.
24. 24. The system according to claim 16 wherein the processing device comprises a mobile switching center.
25. 25. A method for use in a cellular telephone system for assigning traffic channels, comprising the steps of: making signal strength measurements at frequencies assigned to a base station, where each frequency includes a plurality of traffic channels of time segments, the measurement is made at frequencies that have traffic channels of inactive time segments to obtain uplink interference measurements; making a report through a given base station of measurements made on selected frequencies of various frequencies assigned to this given base station including inactive traffic channels, measured signal strengths indicating uplink interference; and processing the reported measurements of uplink interference signal strength for the selected frequencies to be selected for allocation by the given base station of an inactive traffic channel at a frequency less interfered with than possible frequencies selected while being used simultaneously of the smallest possible number of frequencies assigned to this given base station.
26. The method according to claim 25 wherein the step of making signal strength measurements comprises the step of making signal strength measurements for each inactive time segment.
27. The method according to claim 25 wherein the processing step comprises the steps of: applying an interference penalty against the measurements received from uplink interference if the measured frequency includes more than a threshold number of time slot traffic channels inactive; classify the frequencies measured by uplink interference measurements adjusted by any interference penalty applied from a frequency less interfered with uplink to a frequency more interfered with uplink; and selecting for assignment by the base station a channel to establish call or for transfer between the traffic channels of inactive time segments included within the frequency minus interfered by uplink.
28. The method according to claim 27, wherein the step of classifying comprises the step of classifying the frequencies measured by its uplink interference measurements adjusted by any penalty for interference applied to several lists, each list ordered from a frequency less interfered by uplink to a frequency more interfered with uplink.
29. 29. The method according to claim 28 wherein the step of selecting comprises the step of selecting from one or several of the various lists for assigning a channel to establish a call or transfer a call between the traffic channels of segments of inactive time included within the frequency less interfered with uplink contained in said list.
30. 30. The method according to claim 27 wherein the step of applying comprises the step of applying a penalty for increasing interference against the received measurements of uplink interference corresponding to when an increasing number of traffic channels of inactive time segments they are included within the frequency. The method according to claim 27 wherein the step of selecting comprises the step of randomly selecting a channel of inactive time segment traffic included within the frequency minus interfered by uplink. The method according to claim 27 wherein the step of selecting comprises the step of selecting an inactive time segment traffic channel having the least interference included within the least interfering frequency by uplink.