MXPA99005871A - Telecommunications systems - Google Patents

Abstract

A base station comprises a plurality of transceivers, one of which normally performs verifications, but is able to handle traffic channels at time of high demand. When it is desired to block one transceiver, for example for maintenance purposes, calls allocated to that transceiver can be handed off to other transceivers before the device is fully blocked.

Description

TELECOMMUNICATION SYSTEM TECHNICAL FIELD OF THE INVENTION This invention relates to a base station, and to a base station transceiver, and particularly to a method of operation thereof for use in a mobile communication system. Particularly, the invention relates to the efficient use of base station resources. DESCRIPTION OF THE RELATED ART In current cellular telephone systems, using the IS-54 specification, each base station typically includes several transceiver devices. Decisions regarding transfers are based on measurements made by the mobile and on verifications made by the base stations. Each active mobile is continuously measuring the strength of the signal at frequencies transmitted from neighboring base stations. The values are reported to the system that keeps a list of potential target cells for transfer, in the case in which the quality of the current connection falls below an acceptable level. When this occurs, the system may decide that, in order to improve the quality of the connection, a transfer must be made. The system then selects a white cell from the list, and orders that the selected target cell verify that the mobile can be detected with acceptable quality, in order to ensure that the quality of the connection is acceptable after the transfer. This procedure can be repeated with other target cells until an acceptable target cell is found. Verifications are carried out through a dedicated transceiver device located at each base station. The dedicated verification device is often referred to as a SEE device, while the transceiver devices carrying the control channels and traffic channels are often referred to as DVC devices. A small base station can have 3 DVC devices and one VER device, which means that 25% of the cost of the base station equipment refers to the cost of the SEE device since the SEE device and the DVC devices are one comparable complexity. In order to carry out a verification, the VER device tunes its receiver to the frequency used by the mobile phone and first looks for the synchronization sequence, which differentiates the specific mobile to which it refers from the other mobile phones using the other time segments. on the same frequency. The VER device then searches for the color code of the digital voice channel or DVCC in order to verify that they are receiving a signal from the intended mobile. A determination can be made as to the quality of the connection. The verification procedure can be repeated, in order to compensate effects such as fading and shading. COMPENDIUM OF THE INVENTION A problem associated with known base stations is that, particularly in the case of small base stations (pico), the VER device represents a large part of the equipment cost. An object of the present invention is to allow the use of at least one device in a base station to carry out verifications as well as to carry out traffic channels, thus reducing or eliminating the cost of equipment dedicated to the realization of verifications. An additional problem that arises with known base stations is that, from time to time, it is necessary to eliminate traffic from one of the transceiver devices, for example, in order to load a new programmatic, or to perform maintenance. This can be done only by blocking all current calls on this device. An object of the present invention is to allow blocking of a transceiver device without requiring the termination of any current call. Particularly, a first aspect of the invention relates to a base station and to a method of operation of said base station, where a transceiver device that carries out checks can also handle traffic calls. In accordance with a second aspect of the invention, a transceiver device that must be blocked can transfer calls to other transceiver devices within the base station. Beneficially, when a transceiver device carrying out checks can also handle traffic calls, and this device is making traffic calls but other transceiver devices within the base station have free time slots, this transceiver device can transfer calls to the other transceiver devices. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic representation of a base station according to the invention. Figure 2 is a time history of the operating frequency of a transceiver device operating in accordance with the first aspect of the invention. DETAILED DESCRIPTION OF PREFERRED MODALITIES Figure 1 shows a base station 2 according to the invention. The advantages of the present invention are especially noteworthy when applied to small base stations, and base station two is a peak-base station for use in an indoor cellular system, but it can be seen that the invention must be applied to any base station. The base station includes four transceivers 4, 6, 8, 10. The transceivers 4, 6, 8 are used for traffic channels and for the digital control channel. In one embodiment, each transceiver device operates on a respective different frequency, in three time segments, with each time segment assigned to either a traffic channel or the digital control channel. These transceivers 4,6,8 are also placed as transceivers TRX1, TRX2 and TRX3, respectively. The fourth transceiver 10 also has an operating frequency assigned to it and is also divided into 3 time segments. This device is also used to carry out verifications if necessary, and is also known as VER / TRX 4. The transceivers are connected to an array of antennas 12 and, controlled by a base station controller 14. In a system of In the prior art, where the fourth device is reserved for carrying out verifications, said base station could handle a maximum of 8 traffic channels (three time segments in each TRX1, TRX2 and TRX3, with a reserved time segment). for the digital control channel) while in accordance with the present invention the base station can handle up to 11 traffic channels, without requiring additional equipment, since 3 traffic channels can also be assigned to SEE / TRX4. The digital control channel (DCC) is assigned to one of the transceivers 4,6,8, as for example, to the time segment 1 of TRX1. In accordance with preferred embodiments of the invention, when there are 8 or fewer mobiles connected to the base station, they are assigned to transceivers TRXl, TRX2, and TRX3. For example, Table 1 below shows a situation in which the DVCL and DVC2 mobiles are assigned to time segments 2 and 3 respectively of TRXl; the DVC3, DVC4 and DVC5 mobiles are assigned to time segments 1, 2 and 3, respectively of TRX2; and the DVC6 mobile is assigned to time segment 1 of TRX3. The time segments 2 and 3 in TRX3 are not assigned, and the fourth transceiver SEE / TRX4 is free to carry out verifications, as in the prior art. TABLE 1 TRXl TRX2 TRX3 SEE / TRX4 SSeeggmmeennttoo of ttiieemmppoo 11 DCC DVC3 DVC6 Time segment 2 DVC DVC4 Time segment 3 DVC2 DVC5 As more mobile stations are connected to the base station, they are also assigned to TRXl, TRX2 and TRX3. Thus, Table 2 below shows the situation when the mobiles DVC7 and DVC8 have been connected to the base station, in time segments 2 and 3, respectively TRX3. The fourth VER / TRX4 transceiver still does not have traffic channels, and is available to carry out verifications as required. TABLE 2 TRXl TRX2 TRX3 SEE / TRX4 Time segment 1 DCC DVC3 DVC6 Time segment 2 DVCI DVC4 DVC7 Time segment 3 DVC2 DVC5 DVC8 When additional mobiles are connected to the base station, they are assigned to the fourth transceiver device VER / TRX4, which acts after very similar way to the other transceivers, during most of the time. For example, it has a frequency specifically assigned to it. Table 3 below shows a situation in which the mobiles DVC9 and DVC10 have been connected to the time segments 1 and 2 respectively of SEE / TRX4, while the time segment 3 remains free. TABLE 3 TRXl TRX2 TRX3 SEE / TRX4 Time segment 1 DCC DVC3 DVC6 DVC9 Time segment 2 DVCI DVC4 DVC7 DVC10 Time segment 3 DVC2 DVC5 DVC8 When operated in this way, VER / TRX4 is also used to carry out the verifications necessary, as illustrated with reference to Figure 2. Figure 2 shows the time histories of transmissions on two frequencies. The upper line represents transmissions in the operating frequency of the VER / TRX4 device. As mentioned above, the frequency has three time segments, the first of said time segments is assigned to DVC9, the second of said time segments to DVC3, and the third is free. The lower line in Figure 2 represents transmissions on the frequency of a white mobile device, for which the base station is now required to carry out a verification in order to determine whether this mobile device must be transferred to the mobile station. base. The frequency of the mobile device also has 3 time segments, one of which is assigned to the mobile device NX. It will be noted that other mobile devices can be assigned to the other two time segments. Both in the upper line and in the upper line, 3 time segments form a frame, with a duration of 20 ms. As shown in Figure 2, in normal operation, ie when no checks are carried out, the VER / TRX4 device is operating on its own assigned frequency handling traffic from the DVC9 and DVX10 mobiles. At TI time, a check is requested in order to determine if the additional mobile device MX should be assigned to the base station. At this point, the VER / TRX4 device retunes its receiver to a frequency of the mobile device that reaches at time t2. The transceiver VER / TRX4 then remains tuned to the frequency of the white mobile device during at least one frame period, ie 20 ms in the illustrated mode, in order to ensure that it receives a signal from the white mobile mx. During this period, the VER / TRX4 device searches for the mobile using the synchronization sequence, and detects the DVCC. The base station controller 14 then uses signal strength measurements in order to perform the required verification. If desired, the system can be adjusted in such a way that the VER / TRX4 device is tuned to the white moving frequency for a longer period, for example, to allow the repetition of the verification, in order to improve its reliability. At time t3, ie after 20ms, the device SEE / TRX4 is tuned again with its own operating frequency, which reaches at time T4. Thus, the device that is handling the traffic channels can also carry out verification. During the period from ti to t4, the VER / TRX4 device is unable to handle traffic, which means that 1 or 2 time segments for DVC9 and DVC10 are lost. However, it is unlikely that users will notice it. Table 4 below shows the situation in which an additional mobile station DVC11 has been assigned to time segment 3 of SEE / TRX4. TABLE 4 TRXl TRX2 TRX3 SEE / TRX4 Time segment 1 DCC DVC3 DVC6 DVC9 Time segment 2 DVCI DVC4 DVC7 DVC10 Time segment 3 DVC2 DVC5 DVC8 DVC11 In this situation, there is no need to impose any quality degradation on the assigned mobile devices to SEE / TRX4 by performing verifications because it is not possible to assign any additional mobile to the base station, and therefore the verification would have no purpose. It is suggested that, in normal use, the VER / TRX4 device will be used only infrequently for traffic channels, since the capacity of the system must be such that normal loads can be handled by the other TRXl, TRX2, and TRX3 transceivers. However, it is an advantage to be able to use a fourth transceiver to handle calls in peak times. Table 5 below shows a situation after a peak traffic load period has just ended and the situation is returning to normal.

TABLE 5 TRXl TRX2 TRX3 SEE / TRX4 Time segment 1 DCC DVC3 DVCß Time segment 2 DVC DVC11 DVC9 Time segment 3 DVC10 DVC5 DVC8 As calls end, the mobiles assigned to the VER / TRX4 device are transferred to time segments in the other devices, as these time segments become free. Thus, as shown in Table 5, the DVC2, DVC4 and DVC7 mobiles have been disconnected, and the DVC9, DVC10, and DVC11 mobiles have been transferred to time segment 2 in TRX3, time segment in TRXl, and segment of time 2 in TRX2, respectively. Thus, the VER / TRX4 device is now free to carry out verifications again and the DVC9, DVC10 and DVC11 mobiles are no longer subject to small quality degradations previously imposed because they are assigned to the VER / TRX4 device. Thus, this aspect of the invention allows the handling of a greater traffic by a base station. Alternatively, base stations can be designed to employ less equipment than conventionally. A further aspect of the present invention relates to the general use of intracellular transfer as described above with reference to Table 5.

It is often necessary for a system operator to remove a traffic transceiver device, for example, to allow the installation of a new programmatic either due to a device failure, or because the frequency of operation of the device is required for other purposes Currently, when a situation of this type arises, the device is blocked, and all existing calls to mobile and from mobiles assigned to this device are terminated. Obviously this causes discomfort for users. In accordance with the present invention, however, intracellular transfers can be used to avoid this problem. Table 6 below shows a situation in which a time segment 1 of TRXl is being used for the digital control channel (DCC); the DVCL and DVC2 mobiles are assigned to TRXl time segments 2 and 3; the DVC3 and DVC4 mobiles are assigned to the TRX2 time segments 1 and 2; and the DVC5 mobile is assigned to time segment 1 of TRX3. The other time segments are free, and the VER / TRX 4 device is being used for verifications. TABLE 6 TRXl TRX2 TRX3 SEE / TRX4 Time segment 1 DCC DVC3 DVC5 Time segment 2 DVC DVC4 Time segment 3 DVC2 - - Now, if you want to remove TRX2 traffic, for example, to load a new program, the driver base station 14 initiates a soft blocking procedure. Specifically, the DVC3 and DVC4 mobiles are transferred to TRX3, specifically to time segments 2 and 3 as shown in table 7. T7ABLA 7 TRXl TRX2 TRX3 SEE / TRX4 Time segment 1 DCC - DVC5 Time segment 2 DVCl - DVC3 Time Segment 3 DVC2 - DVC4 When these intracell transfers are over, and when TRX2 no longer has traffic, the necessary link can be carried out without causing any of the calls to be disturbed. If the soft block procedure becomes necessary in a relatively high demand time, it may not be immediately possible to transfer calls from the device being blocked. In this case, the intracellular transfer can be carried out only when time segments become available, and the debugging of the cell traffic can be slightly delayed. This can be beneficial for the users of the system, without causing an excessive inconvenience for the system operator. Thus, this aspect of the invention allows the blocking of a transceiver device without requiring the premature termination of calls in progress.

Claims (26)

1. CLAIMS A base station, comprising a plurality of transceivers, each transceiver operates on a respective channel divided into a plurality of time segments, where traffic calls are assigned to time segments in transceivers other than a verification transceiver, leaving the verification transceiver is free to carry out verifications, up to a time such that the time segments in the other transceivers are fully occupied, and where traffic calls are also assigned to the time segments in the verification transceiver. A base station according to claim 1, wherein, when the traffic calls have been assigned to time slots in the verification transceiver, said traffic calls are transferred to other transceivers within the base station as the calls end of traffic assigned to time segments in the other transceivers. A base station according to claim 1, wherein when traffic calls have been assigned to time slots in the verification transceiver, said traffic calls are interrupted to allow the verification transceiver to carry out the necessary verifications. A method of operation of a base station comprising a plurality of transceivers, each transceiver operates in a respective channel divided into a plurality of time segments, the method comprising: assigning traffic calls to time segment in transceivers other than a verification transceiver, thus allowing the verification transceiver to be free to carry out verifications until such time as the time segments in the other transceivers are fully occupied; and the assignment of additional traffic calls to time segments in the verification transceiver. A method of operating a base station according to claim 4, wherein, when traffic calls have been assigned to time slots in the verification transceiver, said traffic calls are transferred to other transceivers within the base station as the traffic calls assigned to time segments in the other transceivers end. A method of operating a base station according to claim 4, wherein when traffic calls have been assigned to time slots in the verification transceiver, said traffic calls are interrupted to allow the verification transceiver to perform the necessary verifications. A method of operation of a base station that has one or more transceivers, the method comprises: performing verifications using a transceiver that can also be used for traffic channels. A base station, comprising one or more transceivers, at least one of said transceivers can be used for both verification and traffic purposes. A base station, comprising: a plurality of transceivers, one of which is used for verifications when capacity permits, but is used for traffic channels when the required number of traffic channels exceeds the number of available traffic channels in the other transceivers. . A base station, comprising a plurality of transceivers, each transceiver in the base station operates at a respective different frequency for traffic signals, where a transceiver operates at its respective different frequency for traffic signals and can be tuned to the frequency from any mobile station to perform verifications. A base station, comprising a plurality of transceivers, each transceiver in the base station operates at a respective different frequency for traffic signals, and having a plurality of time segments, a first time segment in a first transceiver is dedicated to a digital control channel, and a plurality of time segments are dedicated to respective traffic channels, where a second transceiver operates at its respective different frequency for traffic signals and can be tuned to the frequency of any mobile station to carry out verifications during time segments that they become unavailable for traffic. A base station, for use in a cellular telephone system comprising a plurality of mobile stations and a plurality of base stations, each mobile station can ensure an acceptable signal quality before carrying out a transfer from a mobile station. base station to a white base station by transmitting a signal on a specific channel, the white base station then carries out a verification by monitoring the signal from the mobile station, where at least one base comprises a plurality of transceivers, i.e., a verification transceiver and at least one traffic transceiver, and wherein the traffic transceiver or the traffic transceivers are used for traffic signals and a control channel signal, and the Verification transceiver can be used for traffic signals and for verifications. 13. A base station according to claim 12, wherein traffic signal and control channel signal are assigned to the traffic transceiver or to the traffic transceivers until all the channels in the traffic transceiver or traffic transceivers are busy and traffic signals are then assigned to the verification transceiver. 14. A base station according to claim 12, wherein as the channels in the transceiver or traffic transceivers become unoccupied, traffic signals assigned to the verification transceiver are transferred to the unoccupied channels in the transceiver or traffic transceivers. . 15. A base station comprising L transceivers, each of which has a transmission frequency allocated there, and having P time segments, and one of the transceivers is designated as a verification device, wherein one of the segments of time the transceiver other than the verification device is designated as the control channel, and all (P * (N-1) -1) other time segments in the transceiver or transceivers other than the verification device are designated as control channels. traffic, and where the P time segments in the verification device are available for use as traffic channels. A base station according to claim 15, wherein the time slots in the verification device are assigned to traffic channels when the number of traffic channels required exceeds (P * (N-1) -1). A method for allocating channels to transceivers in a base station comprising N transceivers, each having an assigned transmission frequency, and having P time segments, the method comprising the designation of one of the transceivers as a verification device, designating one of the time segments in a transceiver other than the verification device as a control channel, and designating all (P * (Nl) -l) other time segments in the transceiver or other transceivers other than the verification device as traffic channels, while the P-time segments in the verification device are made available for use as traffic channels. A method according to claim 17, further comprising assigning the time slots in the verification device to traffic channels when the number of traffic channels required exceeds (P * (N-1) -l). A method for carrying out a verification using a transceiver, the transceiver is usually tuned to an operating frequency, the communications in the operating frequency are carried out in time segments and a group of time segments form a period of time. In the frame, and respective traffic channels are allocated to respective time segments, the method comprises tuning the transceiver back from the operating frequency to an operating frequency of a mobile during at least one frame period to perform verification, and returning the transceiver to its frequency of operation when verification has been made. A base station transceiver, having an operating frequency, the communications in said transceiver are divided into a time segment, a group of time segments forms a frame period, and each time segment can be assigned to a channel of time. respective traffic, the transceiver can be controlled in order to tune again a frequency of operation of a mobile during at least one frame period, in order to perform a verification on said mobile. A base station, comprising a plurality of transceivers in accordance with claim 20. 22. A base station comprising a plurality of transceivers, and programmed to carry out intracell transfers from a first transceiver to a second transceiver when the first transceiver is to be blocked. 23. A station according to claim 22, wherein each transceiver has a respective operating frequency. 24. A base station according to claim 22, wherein each transceiver has a plurality of time segments, and an intracellular transfer is carried out only when there is a free time segment in the second transceiver. 25. A base station according to claim 22, wherein the first transceiver is not completely blocked until all active calls on the first transceiver have been terminated either transferred to the second transceiver or to respective second transceivers. 26. A method of blocking a transceiver of a base station having a plurality of transceivers, the method comprising sending a blocking signal to the transceiver, transferring all the calls currently being used by the transceiver to the other transceiver, or to other respective transceivers, and blocking the transceiver only when all calls that are currently using the transceiver have been transferred or terminated.