Network based location of mobile transmitters

A method of improving receiver sensitivity, for use in a network-based wireless location system (WLS) associated with an wireless communications network (WCN) with a single carrier frequency division multiple access (SC-FDMA)-based uplink wherein said WCN uses dynamic scheduling of physical resources in both a frequency domain and a time domain, wherein both downlink and uplink radio resources are under control of an eNodeB (eNB), comprising:

• using a semi-persistent-scheduling (SPS) function to enable a location measuring unit (LMU) to integrate uplink signal measurements over longer periods of time;
• wherein a frequency band in which a user equipment device (UE) uplink signal is transmitted is divided into twelve (12) subcarriers in 180 kHz bands, wherein each band is divided in time into 0.5 millisecond slots and the slots are grouped into 1.0 millisecond sub-frames, wherein an intersection of the 12 subcarriers and sub-frames defines a respective resource block (RB);
• wherein the eNB uses the SPS function to set a known pattern of resource blocks for a UE of interest;
• and
• wherein, in the first cycle, the UE of interest is allowed to transmit using two resource blocks, and when a certain UE needs more than one RB, the eNB allocates two or more additional contiguous resource blocks in the frequency domain.

A method of improving receiver sensitivity, for use in a network-based wireless location system (WLS) associated with an wireless communications network (WCN) with a single carrier frequency division multiple access (SC-FDMA)-based uplink wherein said WCN uses dynamic scheduling of physical resources in both a frequency domain and a time domain, wherein both downlink and uplink radio resources are under control of an eNodeB (eNB), comprising:

• using a semi-persistent-scheduling (SPS) function to enable a location measuring unit (LMU) to integrate uplink signal measurements over longer periods of time;
• wherein a frequency band in which a user equipment device (UE) uplink signal is transmitted is divided into twelve (12) subcarriers in 180 kHz bands, wherein each band is divided in time into 0.5 millisecond slots and the slots are grouped into 1.0 millisecond sub-frames, wherein an intersection of the 12 subcarriers and sub-frames defines a respective resource block (RB);
• wherein the eNB uses the SPS function to set a known pattern of RBs for a UE of interest;
• and
• wherein, in a first cycle, the UE of interest is allowed to transmit using RBs, and when a certain UE needs more than one RB, the eNB allocates two or more additional non-contiguous RBs in the frequency domain.

A method of improving receiver sensitivity, for use in a network-based wireless location system (WLS) associated with an wireless communications network (WCN) with a single carrier frequency division multiple access (SC-FDMA)-based uplink wherein said WCN uses dynamic scheduling of physical resources in both a frequency domain and a time domain, wherein both downlink and uplink radio resources are under control of an eNodeB (eNB), comprising:

• using a semi-persistent-scheduling (SPS) function to enable a location measuring unit (LMU) to integrate uplink signal measurements over longer periods of time;
• and
• using a sounding reference signal (SRS) to collect uplink signals over a broader bandwidth;
• wherein the eNB instructs a user equipment device (UE) to transmit an SRS, and the UE's uplink SRS transmission is used by the WLS to enhance the time resolution of the received uplink signal.

A method for improving receiver resolution, for use in a network-based wireless location system (WLS) associated with a single carrier frequency division multiple access (SC-FDMA)-based wireless communications network that relies on dynamic scheduling of physical resources in both a frequency domain and a time domain, wherein both downlink and uplink radio resources are under control of an eNodeB (eNB), comprising:

• using a sounding reference signal (SRS) to enable a location measuring unit (LMU) to collect uplink signal measurements over a broader bandwidth;
• wherein the increased bandwidth of the SRS is used to enhance the performance of time difference of arrival (TDOA)-based location calculations;
• wherein the eNB instructs a user equipment device (UE) to transmit the SRS during uplink time difference of arrival (U-TDOA) locations, and LMUs collect radio frequency (RF) data over a wider bandwidth, thereby enabling more accurate TDOA measurements in a multi-path environment;
• and
• wherein an SRS transmission is transmitted with each orthogonal frequency division multiplexing (OFDM) symbol in a known time/frequency portion of the transmission, and the LMUs involved in a location receive the SRS transmissions from the UE.

A network-based wireless location system (WLS) associated with a single carrier frequency division multiple access (SC-FDMA)-based wireless communications network that relies on dynamic scheduling of physical resources in both a frequency domain and a time domain, wherein both downlink and uplink radio resources are under control of an eNodeB (eNB), wherein a user equipment device (UE) communicates over an air interface to a serving eNB, wherein the air interface comprises an orthogonal frequency division multiple access (OFDMA)-based downlink and an SC-FDMA-based uplink, comprising:

• a network of geographically dispersed location measuring units (LMUs);
• and
• a serving mobile location center (SMLC) configured to communicate with the eNB and to use a semi-persistent-scheduling (SPS) function to enable a least one LMU to integrate uplink signal measurements over longer periods of time;
• wherein the SPS function is employed to set a resource block (RB) allocation pattern for a UE of interest;
• wherein the RB allocation pattern causes the UE of interest to transmit uplink signals in defined RBs of a plurality of time cycles;
• and wherein each RB includes a plurality of sub-carriers spanning a frequency band and time slot in which the UE of interest is permitted to transmit uplink signals.

A network-based wireless location system (WLS) associated with a single carrier frequency division multiple access (SC-FDMA)-based wireless communications network that relies on dynamic scheduling of physical resources in both a frequency domain and a time domain, wherein both downlink and uplink radio resources are under control of an eNodeB (eNB), wherein a user equipment device (UE) communicates over an air interface to a serving eNB, wherein the air interface comprises an orthogonal frequency division multiple access (OFDMA)-based downlink and an SC-FDMA-based uplink, comprising:

• a network of geographically dispersed location measuring units (LMUs);
• and
• a serving mobile location center (SMLC) configured to communicate with the eNB and to use a semi-persistent-scheduling (SPS) function to enable a least one LMU to integrate uplink signal measurements over longer periods of time;
• wherein a frequency band in which the UE uplink signal is transmitted is divided into twelve (12) subcarriers in 180 kHz bands, wherein each band is divided in time into 0.5 millisecond slots and the slots are grouped into 1.0 millisecond sub-frames, wherein the intersection of the 12 subcarriers and sub-frames defines a respective resource block (RB);
• wherein the eNB uses the SPS function to set a known pattern of RBs for a UE of interest;
• wherein, in a first cycle, the UE of interest is allowed to transmit using two RBs, and when a certain UE needs more than one RB, the eNB allocates two or more additional contiguous RBs in the frequency domain.

A network-based wireless location system (WLS) associated with a single carrier frequency division multiple access (SC-FDMA)-based wireless communications network that relies on dynamic scheduling of physical resources in both a frequency domain and a time domain, wherein both downlink and uplink radio resources are under control of an eNodeB (eNB), wherein a user equipment device (UE) communicates over an air interface to a serving eNB, wherein the air interface comprises an orthogonal frequency division multiple access (OFDMA)-based downlink and a SC-FDMA-based uplink, comprising:

• a network of geographically dispersed location measuring units (LMUs);
• and
• a serving mobile location center (SMLC) configured to communicate with the eNB and to use a sounding reference signal (SRS) to enable an LMU to collect uplink signal measurements over a broader bandwidth;
• wherein the SMLC is configured to use the eNB to instruct the UE to transmit an SRS, and the UE's uplink SRS transmission is used by the WLS to enhance the time resolution of the received uplink signal;
• wherein the increased bandwidth of the SRS is used to enhance the performance of time difference of arrival (TDOA)-based location calculations;
• wherein the SMLC is configured to use the eNB to instruct the UE to transmit the SRS during uplink time difference of arrival (U-TDOA) locations, and LMUs collect radio frequency (RF) data over a wider bandwidth, thereby enabling more accurate TDOA measurements in a multi-path environment;
• and
• wherein an SRS burst is transmitted with each orthogonal frequency division multiplexing (OFDM) symbol in a known time/frequency portion of the symbol, and the LMUs involved in a location receive the SRS transmissions from the UE.