AU2013100806A4 - A Radio Resource Allocation Method for Wireless Sensors in Body Area Networks - Google Patents

Abstract

The present invention is related to a radio resource allocation method for wireless sensors in body area network (BAN). This method includes determining the available radio access 5 technologies (RATs) for establishing a communications connection with the user terminal (UT); accessing attribute and policy data for the available RATs; processing the attribute, policy and sensor application data such as: type of application, Quality of Service (QoS) level or emergency condition to generate usage cost data for each of the RATs; and selecting the RAT having the lowest cost of allocation represented by the usage cost data 10 for establishing connection. ................................... ..................................... ............................... ...... ........................................ ....... ........................................ ....... ........................................... ................................ ......... .................. ..... I. .......... .......... ............... ................ I .......... ...... ................ ............ ........................ ........ .... ........................ ...................... .......................... ........... ...... .............. ........ ....... ... .. ................................ ......................... ........... ........... ....................... .......... ...... ............................. ............................. X-7 ....... ..... ................... .............................. ........................ .............................. .............................. .............................. ........... ...................... ....................... ...................... ............... ....... ..................................... ....................... ................. ........................................ ...................................... .......... ............................ .................... .................... ................... .................. ...... ....... ....... ........ ............... ................ ................. ................ ................. ................ ................ C ) ................. .................. ................... C14 ...................... C14 ......................... ........................ ......................... ......................... ......................... ......................... ........................ ........................ ....................... ....................... ....................... ....................... ........................ ........................ ......................... .......................... .......................... ........................... ........................... ............................ ------------------ - ............................ ............................ ............................. ............................ ............................. ............................ ............................ ........................... ........................... ........................... .......................... .......................... ......................... ....................... ....................... ........................ ...................... ....................... ........................ ......................... ......................... .......................... .......................... ......................... .......................... ......................... ......................... LU ...... ..... C) ............ ................................ L L .............. .................... ...... .......................... ............. ............ C14 ............ ............ ........ ............ X.x. .. ......... ... . ........... ........... ...... ........ ........... ....... ........... ..................... ................................... ...................... ............................ ......................................... .............. .. ............................... . .............. ------------------------------- ------------------------------------------- C) C)

Description

- 1 A RADIO RESOURCE ALLOCATION METHOD FOR WIRELESS SENSORS IN BODY AREA NETWORKS FIELD 5 The present invention is related to a radio resource allocation method and system, and a wireless communications user terminal (UT) including a module for use in executing the method that allows at least one wireless sensor to selectively connect to a network using the UT. The sensor may be part of a wireless body area network (WBAN). 10 BACKGROUND A wireless body area network (WBAN) can be used for monitoring and treating patients remotely, and includes a number of different wireless sensors that can be attached 15 to a person's body, clothes or even under a person's skin. The sensors are able to monitor a variety of physiological and psychological functions, including heart rate, body temperature, blood pressure, glucose levels, etc. and generate and transmit data associated with those functions. The data can be sent to an external administration server in a hospital for processing and analysis. The processed data can also be used to invoke or trigger an 20 emergency condition where a SMS or emergency call is made to a doctor or ambulance service for action. The emergency condition may correspond to a heart attack. With the prevalence of cardio vascular diseases and diseases of the circulatory system, the benefits and demand for use of WBANs for health care purposes is increasing. One of the important features for successful use of a WBAN is effective wireless communication. 25 Wireless communications networks are evolving so as to be heterogeneous in nature, in that network service providers or carriers may operate a composite wireless communications network that uses a wide range of different radio access technologies (RATs) supported by respective different radio access networks (RANs). The RANs may 30 include a wide variety of base stations that support the air interfaces of the RATs, and which each connect back to core network infrastructure, such as a mobile switching centre -2 (MSC) of the composite network. The RATs include a wide variety of current and proposed technologies, such as Long Term Evolution (LTE), UMTS Terrestrial Radio Access network (UTRAN) and Wireless Local Area Network (WLAN). 5 A composite network with multiple RATs addresses the issue that no single RAT can support widespread coverage and provide continuous high Quality of Service (QoS) levels over multiple hotspot areas, e.g. office, cafe, community areas, etc. Multiple access networks that support different technologies can be spread in the same geographic space. The Third Generation Partnership Project (3GPP) has developed communication standards 10 for different interconnected heterogeneous wireless network architectures such as Beyond 3G (B3G), LTE and LTE Advanced. B3G interconnects GSM/EDGE Radio Access Network (GERAN), UTRAN and WLAN through a common platform. LTE interconnects with all 3GPP wireless access networks such as GERAN and UTRAN and all non 3GPP wireless access networks such as WLAN and Mobile Worldwide Interoperability for 15 Microwave Access (WiMAX). Wireless communications user terminals (UTs), such as the iPhone and iPad by Apple Inc and the Galaxy terminals produced by Samsung Electronics, have chip sets that support a wide variety of the different available RATs. These multimode UTs can 20 establish a wireless communication connection with available RANs that support different RATs. A number of approaches have been proposed for RAT selection to address the range and complexity of choices for establishing connections or new calls to 25 communications networks, or handle handover between base stations which may support different RATs. Centralised RAT selection methods are executed in the core network equipment, and include load balancing methods and methods that operate according to network 30 operation policies. For example, the centralised methods are executed by the Radio Network Controller (RNC) in B3G networks or by evolved Nodes B (eNode B) in LTE -3 networks. The disadvantage associated with centralised methods are that they rely primarily on the criteria and metrics of the respective RAN, and also reduce network capacity due to the increased signal load and delay associated with the additional communications introduced between network entities. 5 An alternative is to implement a RAT selection method solely within the UT itself, and a method of this nature is referred as a distributed RAT selection method. A distributed method allows the UT to select a RAT that best suits the UT and reduces signalling in the network, thereby improving network capacity. The inherent difficulty 10 however with distributed methods is they operate on the basis of limited data and cannot take into account critical issues, such as the load on network cells, and network policies and operating constraints or preferences. WBAN sensors include a number of different applications that would normally 15 communicate with a health care provider's network or emergency network using a wireless connection to transmit and receive data using one RAT. Each WBAN application, however, may have different requirements for quality of service (QoS), and the RAT will normally only guarantee a required QoS for all applications of the WBAN. Yet some WBAN applications may require a RAT which offers high data rate (e.g WLAN, LTE) 20 such as: electroencephalography (EEG), electrocardiogram (ECG), glucose monitoring, and blood oxygen monitoring. Others may require a RAT which offers low delay and reliable service, because of a detected emergency situation, such as: heart attack, stroke, insulin injection, blockage of breathing path (choking). 25 Accordingly, it is desired to address the deficiencies associated with both of the centralised and distributed methods, and provide a RAT selection approach that is adaptable and takes into account requirements of a WBAN application. It is desired to address the above or at least provide a useful alternative. 30 -4 SUMMARY In accordance with the present invention there is provided a radio access technology (RAT) selection method, executed by a wireless communications user terminal 5 (UT), including: determining RATs of radio access networks (RANs) available for establishing a communications connection with the UT; accessing attribute and policy data for the RATs provided by the RANs; accessing sensor application data associated with at least one sensor connected to 10 the UT; processing the attribute, policy and sensor application data to generate usage cost data for each of the RATs; and selecting the RAT having the lowest cost of allocation represented by the usage cost data for establishing said connection. 15 Advantageously, the sensor application data may represent at least one of: (i) A type of application; (ii) Quality of Service (QoS) level; (iii) Emergency 20 (iv) best UT battery life; and (v) best coverage. The method may be executed for each new connection by the UT or handover of a connection. The attribute and policy data may be provided by radio resource management 25 (RRM) modules of each the RANs. The present invention also provides a wireless communications user terminal (UT) including a terminal radio resource management (TRRM) module for executing the method. 30 The TRRM module may be an application stored on the UT.

-5 DRAWINGS Embodiments of the present invention are hereinafter described, by way of example 5 only, with reference to the accompanying drawings wherein: FIGURE 1 is a block diagram of a remote healthcare system including a wireless body area network and a composite wireless communications network; 10 FIGURE 2 is a block diagram of the composite wireless communications network including components of an embodiment of a RAT selection system; FIGURE 3 is a block diagram of an embodiment of a wireless communications user terminal (UT) including a terminal radio resource management module for executing a 15 RAT selection method; FIGURE 4 is an embodiment of a RAT selection method executed by the TRRM module. 20 DESCRIPTION A remote healthcare system, as shown in Figure 1, includes a wireless body area network (WBAN) 200, equipment 102 of a network access service provider and a healthcare provider network 202 which includes a healthcare administration server 204. 25 The WBAN 200 includes a number of wireless sensor devices 210 located on or adjacent a person's body. The sensors 210 may be located under or on a person's skin or within the person's clothing. The sensors 210 can be used to monitor and obtain personal body data on a variety of physiological and psychological conditions, including the person's body temperature, heart rate, blood pressure, insulin dose, and glucose levels, etc. The wireless 30 sensors 210 are responsible for monitoring the person.

-6 The WBAN 200 allows communication between the sensor devices 210, and with a wireless communications user terminal (UT) 120, using a short distance wave technology such as: Bluetooth (IEEE 802.15.1), ZigBee (IEEE 802.15.4), or Ultra-Wideband (UWB) (IEEE 802.15.4a). Bluetooth has a low cost operates at 2.4 GHz and can offer a high data 5 rates; however, it has a limitation on supporting a maximum number of seven sensor devices 210. ZigBee operates at 800 MHz, 800 MHz and 2.4 GHz, and has the ability to support up to 65,000 sensor devices 210. ZigBee also uses low power consumption, but has a limitation on data rate. It supports a maximum of 250 kbps when operating at 2.4 GHz. UWB is a short range communication technology that has low power consumption 10 with high bandwidth. However, it has a significant transmission loss which makes it unreliable for a WBAN. The sensors 210 of the WBAN are also able to communicate with the healthcare provider network 202 via the equipment 102 of the network access provider. A wireless 15 communications user terminal (UT) 120 located within range of the WBAN 200 provides a connection from the WBAN 200 to the equipment 102 of the network access provider or another service provider. The UT 120 uses one of the available radio access technologies (RATs) supported by networks 104, 106, 108 of the provider, and the RAT is selected depending on the requested service or sensor application, such as "send recorded heart 20 scan" or "send emergency information" or "make an emergency call". The selected network 104, 106, 108 is able to connect to the healthcare provider network 202 using an Internet protocol network (e.g. the Internet) 220. The healthcare administration server 204 of the healthcare provider network 202 is able to process and analyse the received data from the WBAN 200 and generate and send commands to take the appropriate action, such 25 as saving the data in a medical server 224, or contacting a responsible doctor or ambulance service by a variety of communications technologies, such as email, SMS, voice call, etc. A composite wireless communications network is shown in Figure 2 where equipment 102 of the core network infrastructure of a network service provider provides a 30 number of Radio Access Networks (RANs) 104, 106, 108 that use different Radio Access Technologies (RATs), such as Long Term Evolution (LTE), UMTS Terrestrial Radio -7 Access Network (UTRAN) and Wireless Local Area Network (WLAN). Other RANs 110 using respective RATs may be provided by the network equipment 112 of other service providers. The RANs 104 to 110 each provide an air interface for a wireless communications User Terminal (UT) 120 to enable the terminal 120 to selectively connect 5 to the RANs 104 to 110 using their RATs. The network equipment 102, 112 includes computer gateways and computer servers to support the RANs 104 to 110 and provide the composite wireless network, and include one or more mobile switching centres (MSCs) to support and connect to different 10 base stations of the RANs 104 to 110. In particular, each of the RANs 104 to 110 includes or is supported by a Radio Resource Management (RRM) module 134, 136, 138, 140, respectively. The RRMs 134 to 140 are able to provide attribute and policy data for each of their respective RATs to the terminal 120. The attribute and policy data represents a wide variety of network based information for the respective RAT and RAN, including 15 radio resource availability, network policies, supported services, load threshold conditions, data rates, etc. The RRMs 134 to 140 are able to provide the attribute and policy data associated with their respective RAT to the UT 120 using the IEEE P1900.4 protocol standard. The standard supports a collaborative information exchange between the composite network and UTs using a logical communications channel, referred to as the 20 Radio Enabler (RE). The standard supports distributed decision making so as to enable radio spectrum resource usage amongst different RANs to be optimised. The RRMs 134 to 140 may be implemented using computer program code (stored in memory of computer equipment of the networks 102, 112) or embedded code or Application Specific Integrated Circuits (ASICS), to access and deliver the RAT attribute and policy data in accordance 25 with the IEEE P1900.4 protocol. The user terminal 120 when initially used or turned on is able to scan for the available RANs 104 to 110 that can be selected for connection. Authority to access the RANs can be established by using the terminal 120 to execute network setup methods 30 where a network 104 to 110 is added by, for example, simply entering the network name and a security key. Access authority may also be automatically established by network - 8 configuration data stored in a memory module, such as the Subscriber Identity Module (SIM), of the terminal, or downloaded from network configuration services, such as provided by using iTunes of Apple Inc. 5 The UT 120, as shown in Figure 3, includes a microprocessor 124, solid state memory 126 and other hardware components 128, such as wireless chip sets, to support use of the different RATs and communication with the RANs 104 to 110, as well as chip sets for the display and input controls of the terminal 120. The wireless chip sets also support communication with the sensor devices 210 using at least one of the short distance 10 wave technologies, e.g. Bluetooth or ZigBee. The terminal 120 may, for example, be an iPhone or iPad produced by Apple Inc, one of the Galaxy devices by Samsung Electronics or phones produced by HTC Corporation and ZTE Corporation. An operating system (OS) 130 of the terminal, such as iOS or Android, can be stored and updated on the solid state memory 126. The memory 126 can also be used to store computer program code 132 of a 15 Terminal Radio Resource Management (TRRM) module 132 that is able to run on the OS 130. Whilst the TRRM module 132 may be implemented in application code, that can be downloaded as application from a network service, such as the App Store of iTunes, the TRRM module 132 can also be embedded into the hardware components 124, 128 of the terminal 120. The TRRM module 132 could also be implemented as an Application 20 Specific Integrated Circuit (ASIC) or embedded code in a secure element, such as part of the SIM of the terminal 120. The TRRM module 132 is invoked by an event that is issued by the UT 120 and is associated with at least one of the wireless sensors 210. The event may relate to one of the 25 sensors 210 establishing a data communications session or connection with the UT for a WBAN application; or the application sending specific body data or alert data to the UT 120. The application may be associated with one sensor 210 or a number of different sensors 210. The TRRM module 132 could also be invoked by selection of an icon by a user of the terminal 120 to establish communication with at least one sensor 210 or to 30 simply establish communication with the healthcare provider network 202. Different types of sensor applications have different requirements for QoS. For example, some -9 applications may require a RAT which offers high data rate (e.g WLAN, LTE) such as: electroencephalography (EEG), electrocardiography (ECG), glucose monitoring, and blood oxygen monitoring. Others may require a RAT which offers low delay and reliable service, because of an emergency situation, such as: heart attack, stroke, insulin injection, blockage 5 of breathing path (choking). The TRRM 132 executes a RAT selection method 500, as shown in Figure 4, to ensure the application's requirements are taken into account and to improve or guarantee the required QoS for transmission of the application data. The TRRM 132 uses sensor application data representing attributes of the application, such as the application type, and the application data is obtained when the connection request is 10 made by at least one sensor 210 (step 502). The TRRM 132 is able to communicate with the RRMs 134 to 140 of the available RATs to execute the RAT selection method 500 using the attribute and policy data obtained from the RATs and the sensor application data. The method 500 selects from the 15 available RATs the one which will best meet the mode of operation associated with application data. However, the TRRM 132 selects the best RAT and corresponding RAN 104 to 110 based on the application data and network policy and operation data. The RAT selection method 500 can be executed for each new connection to a RAN 104 to 110 or for handover of any existing connection as the UT 120 moves relative to base stations of the 20 RANs. The RAT selection method 500, as shown in Figure 4, is executed by the TRRM 132 and commences when the TRRM 132 detects or receives a connection request, such as from at least one sensor 210, and the UT 120 seeks to make a new data connection or 25 execute a handover (step 502). For a new data communications session requested by one or more sensors 210, the TRRM 132 either receives requests or obtains the application data associated with the sensors 210 and the data communications session. Handover can be horizontal (between two base stations, transmitters or cells) or vertical (between different RANs, e.g. WLAN to UTRAN) or between network operators (e.g. roaming). The TRRM 30 132 obtains Received Signal Strength (RSS) measurement data for each of the available RATs from the RANs (504). The available RATs are then sorted (506) based on signal - 10 strength so those with the strongest received signal strength are processed or considered before the weakest. For each RAT, application cost data is generated (510) and network cost data is generated (508). To determine the network cost data for the best Quality of Service (QoS), the TRRM module 132 obtains all of the QoS attribute data for each of the 5 available RATs using the IEEE P1900.4 protocol. This attribute data represents QoS parameters such as offered data rates, delay, reliability and load level (low, medium or high) of each RAT. RAT policy data is also obtained representing various parameters, such as supported service types and load threshold of each RAT. The attribute and policy data is processed to obtain the network cost data. The network cost data, CN, can be 10 generated using: N S(W x P ) C N N Y W , j=1 where Wj is the factor weight for each network parameter cost, and Pj is the parameter related to allocation of resources in the network, representing the attribute and policy data 15 such as: offered data rates cost (PODR), RAT delay cost (PRD), RAT reliability cost (PRR), load level cost (PLL), supported service type cost (PssT) and load threshold cost (PLTH). Applying this to Equation (1) gives: 20 C WODR ODR +WRD RD +WRR RR +WL xLL +WSST SST +WLTH LTH 20+ CN w w 2) WODR +WRD +WRR +WLL +Wss +WLTH The application cost data, CA, is obtained by processing attribute data associated with the application (i.e. the sensor application data) and use of the UT 120, and may represent requested service type (such as high data rate transmission or emergency or alarm 25 condition) and mobility status (such as high, medium or low mobility). The attribute data representing the requested service type indicates the type of data rate or delay (QoS requirements) that the UT requires and the emergency condition for the requested - 11 application service. The sensor application data could also represent one or more desired modes of operation for the UT 120. The modes of operation may include best UT battery life and best coverage and other modes apparent to a skilled addressee. The mobility status attribute data is important to determine whether the person being monitored is likely to 5 leave an area that may have a better quality of service than another area. For example, if the person is stationary near a WLAN and the UT 120 has a high data rate requirement and low mobility, then its RAT may be selected, as opposed to another RAT (e.g. UTRAN, LTE) being selected if it is likely that the UT 120 is to move away from the WLAN. 10 The application cost data, CA, can be generating using: N S(W x P,) CA- N (3) ~wi 15 dtiuh=s o eqieet (PR1n mre~ ~dtincs PC n OtO where W, is a factor weight for each application parameter cost, and Pi is the parameter related to the usage of resources depending on application status, and represents attribute 15 data such as: QoS requirements (PQR) and emergency condition cost (PEC) and cost of mobility (PM) for the requested application. Applying this to Equation (3) gives: W xP+Wx +W P c WQR QR+WcX EEC +WMXPM CA =~~ (4) WQR +WEC +WM 20 The TRRM 132 executes a cost of radio resources allocation function, C = CN + CA, for each RAT to process the application and network cost data to generate usage cost data for each of the RATs (512). Whilst a number of sophisticated cost functions can be employed, an effective cost function executed by the TRRM 132 assigns a predetermined weight to 25 each of the parameter values of the attribute data and sums the weighted values so as to produce usage cost data for each of the RATs, as described above. The cost data is compared (514) and the RAT with the cost data representing the lowest cost, and hence - 12 best meeting the selected preferred mode, is selected (516). A determination is made as to whether the selected RAT has enough capacity to handle the connection or handover (518) and if it doesn't this RAT is excluded (520) and a determination made as to whether there are remaining RATs from which a selection can be made (522). If so, operation returns to 5 step 516 otherwise the data connection is blocked or dropped (528) if it is determined (524) that the sensor application data does not represent an emergency condition. If the sensor application data is determined to represent an emergency condition at step 524, then a call from the RAT that has the lowest cost is dropped to make radio resources available to transmit the application's data associated with the emergency condition (526) and 10 operation returns to step 506. Once a RAT with the lowest cost is determined to have sufficient capacity to accept the connection or handover (518), the TRRM 132 generates a command (530) to ensure the UT 120 and the selected RAN allocate sufficient, minimum required or maximum allowed radio resources for the requested new connection or handover to use the selected RAT depending on the wireless application type and 15 requirements. The TRRM 132 may then be able to save power by disabling any transmitters and antennas of the UT 120 associated with the unused RATs. Many modifications will be apparent to those skilled in the art without departing from the scope of the present invention.

Claims (5)

1. A radio access technology (RAT) selection method, executed by a wireless communications user terminal (UT), including: 5 determining RATs of radio access networks (RANs) available for establishing a communications connection with the UT; accessing attribute and policy data for the RATs provided by the RANs; accessing sensor application data associated with at least one sensor connected to the UT; 10 processing the attribute, policy and sensor application data to generate usage cost data for each of the RATs; and selecting the RAT having the lowest cost of allocation represented by the usage cost data for establishing said connection. 15

2. A radio access technology (RAT) selection method, as claimed in claim 1, wherein the sensor application data represents at least one of: (i) A type of application; (ii) Quality of Service (QoS) level; (iii) Emergency; 20 (iv) Best UT battery life; and (v) Best coverage.

3. A radio access technology (RAT) selection method, as claimed in any one of the preceding claims, wherein it is for at least one wireless sensor of a body area network 25 and/or the method is executed for each new connection or handover of a connection and/or the attribute and policy data is provided by radio resource management (RRM) modules of each the RANs.

4. A wireless communications user terminal (UT) including a terminal radio resource 30 management (TRRM) module for executing a radio access technology (RAT) selection method as claimed in any one the preceding claims, wherein the TRRM module is an -2 application stored on the UT and/or the TRRM module is an application accessed remotely by the UT, such as from a network server.

5. A terminal radio resource management (TRRM) module of a wireless 5 communications user terminal (UT) configured to execute a radio access technology (RAT) selection method as claimed in any one claims 1 to 3.