Wireless communication device capable of efficient network search
View Patent ↗A wireless communication device is disclosed that is capable of performing efficient network searching. Specifically, by utilizing its location information and accessing stored cell information, the device can streamline searching. Further, if a full search is to be performed, the device receives information from multiple radio access technologies together, and processes the received information digitally in order to search the individual radio access technologies. In addition, the device is capable of performing efficient 4G searches by setting its RF module to capture information of multiple raster points simultaneously within a search band, and shifting the search band so as not to duplicatively search raster points.
1. A wireless communication device capable of communicating within a Long-Term Evolution (LTE) wireless communication environment, the LTE wireless communication environment including a plurality of raster points uniformly distributed therein, the wireless communication device comprising:
a radio module configured to receive signals from the LTE wireless communication environment; and
a controller module configured to set a center frequency and a bandwidth of the radio module to define a search band, wherein the bandwidth of the search band is sufficiently large to encompass two or more adjacent raster points of the plurality of raster points, and to detect a presence or absence of a base station within the search band,
wherein the controller module is configured to determine a raster point within the search band corresponding to a center frequency of the detected base station based on an integer frequency offset relative to the set center frequency of the radio module when the controller module detects the presence of the base station within the search band based on a primary synchronization signal associated with the base station, and
wherein after determining the raster point corresponding to the center frequency of the detected base station, the controller module is configured to shift the center frequency of the radio module by a bandwidth shift frequency substantially equal to a bandwidth of the base station plus a difference between a previous center frequency of the radio module and the detected center frequency of the base station.
2. The wireless communication device of claim 1 , wherein the controller module is configured to detect the presence or absence of the base station within the search band by detecting whether the primary synchronization signal associated with the base station is within the search band.
3. The wireless communication device of claim 1 , wherein the controller module is further configured to shift the center frequency of the radio module by a jump shift frequency greater than a frequency spacing between adjacent raster points when the controller module detects the absence of the base station within the search band.
4. The wireless communication device of claim 3 , wherein the jump shift frequency is equal to the bandwidth of the search band.
5. The wireless communication device of claim 3 , wherein the jump shift frequency is less than the bandwidth of the search band.
6. The wireless communication device of claim 1 , wherein the controller module is further configured to, calculate a frequency offset of the radio module relative to the base station when the controller module detects the presence of the base station within the search band.
7. The wireless communication device of claim 6 , wherein the frequency offset includes a fractional frequency portion and an integer frequency portion.
8. The wireless communication device of claim 7 , wherein the integer frequency portion is a representation of a number of orthogonal frequency-division multiplexing (OFDM) sub-carriers between the center frequency of the radio module and a raster point nearest a center frequency of the base station.
9. The wireless communication device of claim 6 , wherein the controller module is configured to update a clock frequency and a center frequency of the radio module based on the calculated frequency offset.
10. The wireless communication device of claim 1 , wherein a frequency separation between adjacent raster points is 100 kHz.
11. The wireless communication device of claim 1 , wherein the bandwidth of the search band set by the controller module is equal to a frequency spacing between a first raster point and a second raster point.
12. The wireless communication device of claim 1 , wherein the bandwidth of the search band set by the controller module is 500 kHz.
13. The wireless communication device of claim 1 , wherein the controller module is configured to initially set the center frequency of the search band to be equal to a raster point nearest a central frequency of the search band having a lowest frequency aligned with a first raster point in an LTE frequency band.
14. The wireless communication device of claim 1 , wherein the controller module is configured to initially set the center frequency of the search band to be 200 kHz.
15. The wireless communication device of claim 1 , wherein the bandwidth of the base station is acquired from the detected base station.
16. The wireless communication device of claim 1 , wherein the bandwidth of the base station is assumed to be a minimum base station bandwidth as set by a corresponding communication standard.
17. The wireless communication device of claim 1 , wherein the bandwidth of the base station is calculated from a found bandwidth acquired from the detected base station, and a minimum bandwidth defined by a corresponding communication standard.
18. The wireless communication device of claim 17 , wherein the bandwidth of the base station is calculated by determining a maximum value from among the minimum bandwidth and an average of the minimum bandwidth and the found bandwidth.
19. The wireless communication device of claim 1 , wherein after the controller module shifts the center frequency of the radio module by the bandwidth shift frequency, the controller module further shifts the center frequency of the radio module by a first number of raster points less than or equal to a second number of raster points that are encompassed by the bandwidth of the search band.
20. The wireless communication device of claim 19 , wherein the first number of raster points is equal to a ceiling of the second number of raster points divided by 2.