CELLULAR NETWORK AVAILABILITY ENHANCEMENT
Technical Field
The present disclosure relates to a wireless network, and more specifically, but not limited to, for enhancement of wireless network service availability.
Glossary
Base Transceiver Station Site - includes at least a BTS, one or more power converters, a charge storage device, a monitoring unit and a control unit.
Power sources - includes AC/DC power supply, solar, or wind.
Charge storage device - includes bank of batteries
Background
The frequency of power supply outage is quite high in the rural areas. Wireless communication networks operating in such environments are therefore constrained to rely on alternate sources of power frequently and for long periods. While such power sources may be available, the maintenance of such systems is itself a major logistics and management issue. Consequently, it is essential to provide batteries as backup source of power in order to maintain operation during such outage periods. It is desirable that these batteries operate the communication system as long as possible to maintain service availability. However, existing wireless communication sites continue to function at full load capacity throughout the battery operation period, resulting in rapid discharge of batteries. When the batteries drain to the minimum threshold level, the system shuts down rendering all network services unavailable.
Summary
It is an object of the present disclosure to provide an arrangement for enhancement of communication network service availability with graceful reduction in the capacity of the network
load when the state of charge goes below a threshold level, thereby providing longer effective operation of network subsystems.
An embodiment of the present disclosure illustrates a Base Transceiver Station site capable of providing enhanced network availability comprising one or more power converters configured to provide a plurality of switchable power outputs, a plurality of subsystems powered through said switchable power outputs, one or more charge storage devices coupled to said power converters, each said charge storage device having a monitoring unit coupled to it for providing power and charge level status of said charge storage device to a remotely located Base Station Controller (BSC); and a control unit coupled to control inputs of said switchable power outputs for selectively enabling said subsystems based on control signals from said Base Station Controller.
Another embodiment of the present disclosure illustrates a Base Station Controller capable of controlling one or more base transceiver station sites and providing enhanced network availability, said Base Station Controller comprising means for receiving power and charge status information from a Base Transceiver Station site and means for providing control signals to said Base Transceiver Station site for enabling selective shutdown of the BTS wireless network subsystems.
Another embodiment of the present disclosure illustrates a method for enhancing network availability by selective shutdown of wireless network subsystems at the wireless Base Transceiver Station site, said method comprising providing monitored power and charge level status information to a Base Station Controller (BSC) and receiving control signals from said Base Station Controller for selective shutdown of BTS site wireless network subsystems.
Brief Description of the Drawings
For a better understanding of the embodiments of the systems and methods described herein, and to show more clearly how they may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, wherein:
FIGURE 1 illustrates a block diagram of an arrangement for enhancement of wireless network availability in accordance with an embodiment of the present disclosure.
FIGURE 2 illustrates an internal arrangement of the BTS subsystems in different 'sets' in accordance with an embodiment of the present disclosure.
FIGURE 3 illustrates a graphical representation of wireless network availability enhancement according to an embodiment of the present disclosure.
Detailed Description
Exemplary embodiments now will be described with reference to the accompanying drawings. The disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. The terminology used in the detailed description of the particular exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting. In the drawings, like numbers refer to like elements.
The specification may refer to "an", "one" or "some" embodiments) in several locations. This does not necessarily imply that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.
As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms "includes", "comprises", "including" and/or "comprising" when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. Furthermore, "connected" or "coupled" as used herein may include operatively connected or coupled. As used herein, the term "and/or" includes any and all combinations and arrangements of one or more of the associated listed items.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure
pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
"Wireless communication system" includes any communication system or any combination of different communication systems. The communication system may be a fixed communication system or a wireless communication system or a communication system utilizing both fixed networks and wireless networks. The protocols used the specifications of communication systems, servers and user terminals, especially in wireless communication, develop rapidly. Such development may require extra changes to an embodiment. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict the embodiment.
The figures depict a simplified structure only showing some elements and functional entities, all being logical units whose implementation may differ from what is shown. The connections shown are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art that the structure may also comprise other functions and structures. It should be appreciated that the functions, structures, elements and the protocols used in communication are irrelevant to the present disclosure. Therefore, they need not be discussed in more detail here.
Also, all logical units described and depicted in the figures include the software and/or hardware components required for the unit to function. Further, each unit may comprise within itself one or more components which are implicitly understood. These components may be operatively coupled to each other and be configured to communicate with each other to perform the function of the said unit.
Figure 1 illustrates a block diagram of an arrangement for enhancement of wireless network availability according to an embodiment of the present disclosure. The arrangement comprises a base transceiver station site which includes a Base Transceiver Station (BTS) 101, one or more power sources 102 configured to provide power supply, one or more charge storage devices 103 such as battery banks, each said charge storage device having a monitoring unit 104 coupled to it for providing power and charge level status of said charge storage device to a remotely located Base Station Controller (BSC), and a control unit 105 coupled to control inputs of said switchable power outputs for selectively enabling said subsystems based on control signals from said Base Station
Controller, and one or more power converters 106 configured to provide power to various subsystems of BTS. Further, the Base Station Controller (BSC) 107 includes an Operation, Administration and Maintenance (OAM) unit 108 and a BTS management unit 109. Furthermore, wireless BTS comprises multiple hardware subsystems such as several transceivers, radio amplifier, active combiners etc. It will be further understood that power source, includes any power source or any combination of multiple power sources such as AC/DC, solar, wind etc.
According to an embodiment of the present disclosure, during regular operation of the wireless network, the monitoring unit 104 located at the BTS site is configured to constantly monitors the following parameters related to power and charge level such as charging current (I-charging) into the charge storage device, drain current (I-drain) from said charge storage device towards the Base Transceiver Station 101 and the charge level (BB-cLevel) of the charge storage device. The output of the monitoring unit is constantly forwarded to the remotely located Base Station Controller (BSC) 107 which is further forwarded to the OAM unit 108. When the charge level of the battery starts decreasing, the OAM unit 108 instructs the BTS management unit 109 to manage the network by providing instructions regarding shut down of low priority subsystems to the control unit 105 located at the BTS site. The optimization of network functions with regard to the available power is handled by the BTS management unit 109 and necessary actions are taken by the control unit 105 located at the BTS site. According to an embodiment, the control unit 105 and the BTS management unit 109 are coupled through a radio link or a terrestrial link. Thus, the network availability is ensured by determining the high priority functions of the network to continue functioning with gradual reduction in the capacity by shutting down low priority functions.
Figure 2 illustrates an internal arrangement of the BTS subsystems in different 'sets' in accordance with an embodiment of the present disclosure. The Base Transceiver Station (BTS) 101 contains various subsystems for transmitting and receiving radio signals (transceivers), antennas, combiners and subsystems for encrypting and decrypting communications with the Base Station Controller (BSC). Typically a BTS has several transceivers (TRXs) which allow it to serve different frequencies and different sectors of the cell (in the case of sectorised base stations). A BTS is controlled by a parent BSC via the Base Station Control Function (BCF). The BCF is implemented as a discrete unit or incorporated in a TRX in compact base stations. It couples the Operations and Maintenance (OAM) unit with wireless network management system (NMS), and manages operational states of each TRX, as well as software handling and alarm collection.
According to an embodiment of the present invention, the GSM broadcast function is implemented on one TRX (transceiver). The GSM broadcast function uses a Broadcast Control Channel (BCCH) with the highest priority. Similarly, there are several other GSM functions which are implemented by assigning a fixed weight to each of the functions. These functions and their respective weights are such as BCCH = 1000, SDCCH = 500, TCH = 100, PDCH =100, and BCCH_Combined= 1500.
Further, according to embodiments of the present invention, a 'set' implements one or more GSM functionalities. The total weight of each set is projected based on the implemented GSM functions. The total weight of each set is sum of all the functions and their assigned weights. Each 'set' is assigned priority based on its functionality and greater value of weight. The highest priority 'set' includes functionalities which are must for network services to be available. The lower priority 'set' contains functionalities which can be shutdown and network services is still available but with reduced capacity. Secondly, mechanism to shutdown and power-on each 'set' is defined between BTS and the BSC. Shutdown of 'set' is carried out in the pre-defined priority order of the sets and this does not affect functionality belonging to other sets.
According to an embodiment of the present disclosure, the following configurable matrix shows a predefined relation between charge level and the different set of subsystems. This particular embodiment illustrates 10 sets implementing GSM functions:

(Table Removed)
During normal operation, the OAM unit (Operation and Maintenance) 108 is configured to periodically invokes the monitoring and control unit (104, 105) for collection of monitoring and control information from the BTS site. Various threshold levels of battery charge level are defined in OAM unit. The OAM unit provides a mechanism to prioritize the 'sets' of subsystems at the BTS site based on the charge threshold level (CTL). When the charge level is falling, the subsystems in reverse priority order are shut down gracefully. When the charge level is rising, the subsystems are power-on
in the priority order. In the following illustration, SET-0 has highest priority subsystems and THRESHOLD-xO is the minimum charge level.
Figure 3 illustrates the performance of the charge storage device with respect to the time according to an embodiment of the present disclosure. As the battery charge level decreases with time, the network service availability gradually decreases towards the threshold value of charge unlike the conventional art where the charge level used to rapidly decrease thereby, making the wireless network services completely unavailable. According to the graph, the portion 301(a) indicates that all 'sets' are functioning normal and there is no lack of power. As time increases, the available charge starts decreasing. Thus, the graph portion 301(b) indicates that only higher priority 'sets' are functionally active while lowest priority 'sets' are shutdown. The graph portion 301(c) further indicates that only highest priority 'sets' are active while remaining 'sets' are shutdown as the battery charge level has decreased to its minimum value. The graph 302 shows wireless network performance according to conventional art where there was an abrupt shutdown of the complete network when the charge level goes below the threshold level.
Embodiments of the wireless network availability enhancement as disclosed in the present disclosure provide monitoring and control mechanism to manage the wireless base transceiver station site. The monitoring of power unit through a monitoring and control unit and managing the wireless network availability from the BSC allows graceful capacity reduction, instead of rendering the services completely unavailable.
The present disclosure is applicable to all types of wireless BTS sites of a wireless network located in rural or roadside areas.
It should be understood that embodiments of the present disclosure may be included in various types of wireless communication networks intended to be within the scope of the present disclosure, although not limited to, a GSM network, a CDMA network, a worldwide interoperability for microwave access (WiMAX) network, a WCDMA network, a time division synchronous code division multiple access (TD-SCDMA) network, a CDMA2000 network, a personal handy phone system (PHS) network, a cluster network, a long term evolution (LTE) network, and an air interface evolution (AIE) network.
It will be apparent to those having ordinary skill in this art that various modifications and
variations may be made to the embodiments disclosed herein, consistent with the present disclosure,
without departing from the spirit and scope of the present disclosure.
Other embodiments consistent with the present disclosure will become apparent from consideration
of the specification and the practice of the description disclosed herein.

We claim:
1. A Base Transceiver Station site capable of providing enhanced network availability
comprising:
- one or more power converters configured to provide a plurality of switchable power outputs
- a plurality of subsystems powered through said switchable power outputs;
- one or more charge storage devices coupled to said power converters;
- each said charge storage device having a monitoring unit coupled to it for providing power and charge level status of said charge storage device to a remotely located Base Station Controller (BSC); and
- a control unit coupled to control inputs of said switchable power outputs for selectively enabling said subsystems based on control signals from said Base Station Controller.
2. The Base Transceiver Station site as claimed in claim 1, wherein said power and charge level
status is provided for parameters:
charging current (I-charging) into said charge storage device; drain current (I-drain) from said charge storage device; and charge level (c-level) of said charge storage device.
3. The Base Transceiver Station site as claimed in claim 1, wherein said selective shutdown of
said subsystems is according to a predetermined priority sequence.
4. The Base Transceiver Station site as claimed in claim 3, wherein the predetermined priority sequence is determined by essentiality of functions used to maintain the availability of the network.
5. A Base Station Controller capable of controlling one or more base transceiver station sites and providing enhanced network availability, said base station controller comprising:
means for receiving power and charge status information from a base transceiver station site; and
means for providing control signals to said Base Transceiver Station site for enabling selective shutdown of the BTS subsystems.
6. The Base Station Controller as claimed in claim 5, wherein said selective shutdown of said subsystems is according to a predetermined priority sequence.
7. The Base Station Controller as claimed in claim 6, wherein the predetermined priority sequence is determined by essentiality of functions used to maintain the availability of the network.
8. The Base Station Controller as claimed in claim 5, wherein said means for receiving power and charge status information is an Operation, Administration and Maintenance Unit.
9. The Base Station Controller as claimed in claim 5, wherein said means for providing control signals is a BTS Management Unit.
10. A wireless network comprising one or more base transceiver station sites for providing enhanced network availability, said base transceiver station site comprising:
one or more power converters configured to provide a plurality of switchable power outputs;
a plurality of subsystems powered through said switchable power outputs;
one or more charge storage devices coupled to said power converters;
each said charge storage device having a monitoring unit coupled to it for providing power and charge level status of said charge storage device to a Base Station Controller (BSC); and
a control unit coupled to control inputs of said switchable power outputs for selectively enabling said subsystems based on control signals from said Base Station Controller.
11. A method for providing enhanced network availability by selective shutdown of wireless
network subsystems at the Base Transceiver Station site, said method comprising:
providing monitored power and charge level status information to a Base Station Controller (BSC); and
receiving control signals from said Base Station Controller for selective shutdown of BTS site subsystems.
12. The method as claimed in claim 11, wherein said selective shutdown of said subsystems is
according to a predetermined priority sequence.
13. The method as claimed in claim 11, wherein the predetermined priority sequence is determined by essentiality of functions used to maintain the availability of the network.