Abstract:
A base station determines whether a mobile unit should handoff based upon the battery level and battery drain of the mobile unit battery. The battery level and battery drain are sent from the mobile unit to the base station. The base station uses this information to determine whether the mobile unit should power up or power down LTE-U or WiFi radio connections and services. In addition, this information allows the base station to determine whether the mobile unit should handoff between LTE-L and LTE-U base stations, in order to control power consumption of the mobile unit and prolong the battery life of the mobile unit.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to communication systems. 
       BACKGROUND OF THE INVENTION 
       [0002]    A battery in a mobile device carries a charge. The battery charge and drain rate are currently measurable at some mobile devices. However, this information is typically not known by network elements. 
         [0003]    Handing off to other base stations consumes more mobile unit battery power than remaining at a current base station due to the powering up of multiple radios. Multiple handoffs of a mobile unit with low battery power can consume enough power of the mobile unit that the mobile unit runs out of battery power and will not be functional until the battery is recharged or replaced. 
         [0004]    Therefore, a need exists for a way to allow handoffs of mobile units without consuming too much power from the battery of the mobile unit. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    An exemplary embodiment of the present invention provides for a determination of whether a mobile unit should handoff based upon the battery level and battery drain of the mobile unit battery. The battery level and battery drain are sent from the mobile unit to a base station. The base station uses this information to determine whether the mobile unit should power up or power down LTE-U and/or WiFi radio connections/services. In addition, this information allows the base station to determine whether the mobile unit should handoff between LTE-L and LTE-U base stations, in order to control power consumption of the mobile unit and prolong the battery life of the mobile unit. 
         [0006]    The base station preferably calculates the transmitting power for LTE-L/LTE-U per channel/path and compares this required power level with the status of the battery level and battery drain rate of the mobile unit, with different level thresholds, to control the power and battery life for the mobile unit. 
         [0007]    In addition, with power control calculations, the base station is developed with new methods and able to mute some cells, such as LTE-L and LTE-U base stations, using coordinated scheduling, in order to prolong the battery life of the mobile unit. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0008]      FIG. 1  depicts the functional architecture of a communication network in accordance with an exemplary embodiment of the present invention. 
           [0009]      FIG. 2  depicts a call flow diagram in accordance with an exemplary embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0010]      FIG. 1  depicts the functional architecture of a wireless communication network  100  in accordance with an exemplary embodiment of the present invention. Communication network  100  preferably includes base station  104 , Metro eNBs  102  and  112 , and mobile unit  103 . It should be understood that additional network elements can be included in communication network  100 , but only these elements are depicted for clarity. 
         [0011]    Wireless network  100  is a wireless communication network that provides subscribers the ability to place and receive calls to other communication units. Network  100  can utilize any wireless network protocol, including but not limited to 3G, WCDMA, CDMA2000, LTE and WiMAX. 
         [0012]    In accordance with an exemplary embodiment, wireless network  100  authorizes carrier grade WiFi. Carrier grade WiFi can preferably belong to any third parties equipped with carrier grade functions. In accordance with an exemplary embodiment, wireless network  100  sets the priority of authorized WiFi which are in the vicinity of multiple small cells or macro cells. 
         [0013]    In accordance with an exemplary embodiment, wireless network  100  provisions a list of authorized WiFi candidate cells into a handover candidate list. The cells can be small cells, macrocells, or both. The list can be static or dynamic. Small cells preferably know the coverage and transmit power strength of WiFi transmitters in the list. In LTE systems, small cells can shift data service to authorized WiFi for LTE service. 
         [0014]    Base station  104  is preferably a macro Evolved Node B (eNodeB or eNB). Base station  104  provides radio coverage within a macrocell  194  using licensed spectrum. Base station  104  is a wireless base station that communicates with mobile units within macrocell  194  and connects the mobile units to the land-line network for call completion. Base station  104  preferably includes a receiver, a transmitter, a processor, and memory. 
         [0015]    Metro eNBs  102  and  112  each comprise a small, low-power cellular base station. Metro eNBs can alternately be referred to as small cells. 
         [0016]    In an exemplary embodiment, carrier grade WiFi is integrated within metro eNBs  102  and  112 . Alternately, carrier grade WiFi is standalone and co-located with metro eNBs  102  and  112 . 
         [0017]    In accordance with the exemplary embodiment, metro eNBs  102  and  112  each include three coverage areas: a carrier-grade WiFi coverage area, a metro LTE eNB unlicensed carrier coverage area, and a metro LTE eNB licensed carrier coverage area. In the exemplary embodiment depicted in  FIG. 1 , metro eNB  102  includes carrier-grade WiFi coverage area  160 , metro LTE eNB unlicensed carrier coverage area  170 , and metro LTE eNB licensed carrier coverage area  180 . In the exemplary embodiment depicted in  FIG. 1 , metro eNB  112  includes carrier-grade WiFi coverage area  161 , metro LTE eNB unlicensed carrier coverage area  171 , and metro LTE eNB licensed carrier coverage area  181 . 
         [0018]    Mobile unit  103  includes an interface, a receiver, a transmitter, a processor, and memory. In the exemplary embodiment depicted in  FIG. 1 , mobile unit  103  is located in coverage area  194  and served by macro eNB  104 . 
         [0019]      FIG. 2  depicts a call flow diagram  200  in accordance with an exemplary embodiment of the present invention. Carrier grade WiFi access points (APs) commonly charge lower rates for wireless data usage. An exemplary embodiment determines whether a mobile unit has sufficient battery power to make a handoff to an LTE-U base station or a WiFi access point logical. If so, the mobile unit is handed over to the LTE-U base station or the WiFi AP. 
         [0020]    In accordance with an exemplary embodiment, base station  104  sends Request Report Message  201  to mobile unit  103 . Request Report Message  201  is a request for mobile unit  103  to report the battery level and the drain rate of the battery in mobile unit  103 . In accordance with an exemplary embodiment, base station  104  sets a time window and report interval, with a timer or the like. 
         [0021]    Mobile unit  103  sends Battery Measurement Message  203  to base station  104  in response to Request Report Message  201 . Battery Measurement Message  203  preferably includes the current battery level and drain rate of mobile unit  103 . Base station  104  retrieves the battery level and drain rate from Battery Measurement Message  203 . 
         [0022]    In accordance with an exemplary embodiment, base station  104  utilizes the battery level and drain rate to analyze the status and trend of battery usage of mobile unit  103 . Base station  104  preferably determines a threshold value at which base station  104  will instruct mobile unit  103  to disable LTE-U and WiFi connections. In addition, base station  104  can utilize the threshold value to determine whether to instruct mobile unit  103  whether mobile unit  103  should handoff between LTE-L and LTE-U base stations. 
         [0023]    In accordance with an exemplary embodiment, base station  104  can utilize any combination of battery status and additional characteristics to determine the threshold value. Battery status preferably includes the battery level and the drain rate of the battery in the mobile unit. Additional characteristics preferably include required transmitting power, signal-to-noise ratio, and smart charging. 
         [0024]    Base station  104  sends Instruction Message  205  to mobile unit  103 . Instruction Message  205  preferably includes an enable LTE-U flag and an enable WiFi flag. If the enable LTE-U flag is set to Yes, it indicates that base station  104  wants to instruct mobile unit  103  to enable LTE-U connections and service, and if the enable LTE-U flag is set to No, it indicates that base station  104  wants to instruct mobile unit  103  to disable LTE-U connections and services. If the enable WiFi flag is set to Yes, it indicates that base station  104  wants to instruct mobile unit  103  to enable WiFi connections and service, and if the enable WiFi flag is set to No, it indicates that base station  104  wants to instruct mobile unit  103  to disable WiFi connections and services. 
         [0025]    Mobile unit  103  receives Instruction Message  205 . In accordance with an exemplary embodiment, if the enable LTE-U flag is set to Yes, mobile unit  103  enables LTE-U radio service. If the enable LTE-U flag is set to No, mobile unit  103  disables LTE-U radio service. In accordance with an exemplary embodiment, if the enable WiFi flag is set to Yes, mobile unit  103  enables WiFi radio connections and services. If the enable WiFi flag is set to No, mobile unit  103  disables WiFi radio connections and services. In accordance with an exemplary embodiment, mobile unit  103  notifies the user of mobile unit  103  with the battery level status and enabling or disabling of LTE-U and WiFi services. 
         [0026]    In addition, base station  104  preferably utilizes the threshold to determine whether mobile unit  103  has sufficient battery power to handoff to an LTE-L or LTE-U base station. In an exemplary embodiment, if a WiFi connection requires higher transmitting power and the battery level of mobile unit  103  is under a threshold level, base station  104  will instruct mobile unit  103  not to handover to the WiFi connection regardless of the status of the WiFi connection, such as the WiFi connection providing superior signaling, greater coverage area, or charges a lower tariff. 
         [0027]    In accordance with an exemplary embodiment, total transmitting power of mobile unit  103  is calculated per all of LTE-L, LTE-U and WiFi channels. Each channel path loss is preferably calculated individually. Each channel transmitting power is a summation of nominal power, which is a function of target SINR and interference level, and path loss, which may consider the fractional power control (FPC). 
         [0028]    Base station  104  sends power control value message  207  to mobile unit  103 . Power control value message  207  preferably includes the power control value for each channel or path available, such as the LTE-L paths, the LTE-U paths, and the WiFi paths. 
         [0029]    While this invention has been described in terms of certain examples thereof, it is not intended that it be limited to the above description, but rather only to the extent set forth in the claims that follow.