Detecting the number of transmit antennas in a base station
Data is scrambled at a transmitter according to one of a number of predetermined scrambling sequences which are associated with a particular one of a number of predetermined transmit antenna diversity schemes (i.e., a specific number of transmit antenna ports). Received data is decoded using one or more of the known transmit antenna diversity schemes and the scrambled data is descrambled according to a corresponding descrambling sequence (related to the scrambling sequence). Based on the descrambled data, the receiver determines which transmit antenna diversity scheme (i.e., the number of antenna ports) is used by the transmitter. In one specific embodiment, CRC parity data is scrambled in the transmitter and the receiver descrambles the recovered CRC parity data according to a descrambling sequence, computes CRC parity data from the received data, and compares the descrambled CRC parity data to the newly computed CRC parity data.
1. A method comprising:
selecting, by a communications device in a wireless communication network, a scrambling sequence from a plurality of scrambling sequences dependent upon a number of transmit antennas at a transmitter, wherein the selected scrambling sequence indicates the number of transmit antennas that the transmitter operates with; and
scrambling, by the communications device, a plurality of bits of broadcast channel data using the selected scrambling sequence.
2. The method of claim 1 , wherein the broadcast channel data comprises transport data and cyclic redundancy check (CRC) data, wherein the CRC data is computed based on the transport data.
3. The method of claim 1 , further comprising transmitting, by the communications device, the plurality of scrambled bits within a data frame to a remote communication device, wherein the plurality of scrambled bits are transmitted using a plurality of resource elements.
4. The method of claim 1 , further comprising transmitting, by the communicationsdevice, the plurality of scrambled bits within a broadcast channel in accordance with a Long Term Evolution (LTE) standard.
5. The method of claim 4 , wherein the broadcast channel uses seventy-two subcarriers.
6. A communications device comprising memory and at least one processor coupled to the memory, wherein the at least one processor is configured to execute instructions stored on the memory such that when executed, cause the communications device to:
select a scrambling sequence from a plurality of scrambling sequences dependent upon a number of transmit antennas, wherein the selected scrambling sequence indicates the number of transmit antennas that the communications device operates with; and
scramble a plurality of bits of broadcast channel data using the selected scrambling sequence.
7. The communications device of claim 6 , wherein the broadcast channel data comprises transport data and cyclic redundancy check (CRC) data, wherein the CRC data is computed based on the transport data.
8. The communications device of claim 6 , wherein the communications device is configured to transmit the plurality of scrambled bits to a remote communication device, wherein the plurality of scrambled bits are transmitted using a plurality of resource elements.
9. The communications device of claim 6 , wherein the communications device transmits, to a remote communication device, the plurality of scrambled bits within a broadcast channel in accordance with a Long Term Evolution (LTE) standard.
10. The communications device of claim 9 , wherein the broadcast channel uses seventy-two subcarriers.
11. A method for use with long term evolution (LTE) broadcast channel data, the method comprising:
selecting, by a communications device in an LTE network, a scrambling sequence from a plurality of scrambling sequences dependent upon a number of transmit antennas at a transmitter;
scrambling, by the communications device, at least a portion of the LTE broadcast channel data using the selected scrambling sequence; and
transmitting, by the communications device in a LTE data frame, at least the scrambled LTE broadcast channel data using at least one antenna, wherein the scrambling sequence associated with a particular number of antennas is unique.
12. The method of claim 11 , wherein scrambling at least a portion of the LTE broadcast channel data comprises scrambling the portion of LTE broadcast channel data using a first scrambling sequence when said transmitting uses only one antenna and using a second scrambling sequence when said transmitting uses only two antennas.
13. The method of claim 11 , wherein the LTE broadcast channel data comprises transport data and cyclic redundancy check (CRC) data, wherein the CRC data is computed based on the transport data.
14. The method of claim 11 , wherein transmitting at least the scrambled LTE broadcast channel data further comprises transmitting at least the scrambled LTE broadcast channel data within a broadcast channel in accordance with a LTE standard.
15. The method of claim 14 , wherein the broadcast channel uses seventy-two subcarriers.
16. A communications device comprising a transceiver for transmitting Long Term Evolution (LTE) broadcast channel data, the communications device further comprising memory and at least one processor coupled to the memory, wherein the at least one processor is configured to execute instructions stored on the memory such that when executed, cause the communications device to:
select a scrambling sequence from a plurality of scrambling sequences dependent upon a number of transmit antennas at a transmitter;
scramble at least a portion of the LTE broadcast channel data using the selected scrambling sequence; and
transmit, via the transceiver in a LTE data frame, at least the scrambled LTE broadcast channel data using at least one antenna, wherein the scrambling sequence associated with a particular number of antennas is unique.
17. The communications device of claim 16 , wherein the communications device is configured to scramble at least a portion of LTE broadcast channel data using a first scrambling sequence when the communications device transmits using only one antenna and using a second scrambling sequence when the communications device transmits using only two antennas.
18. The communications device of claim 16 , wherein the LTE broadcast channel data comprises transport data and cyclic redundancy check (CRC) data, wherein the CRC data is computed based on the transport data.
19. The communications device of claim 16 , wherein the communications device is further configured to generate the LTE broadcast channel data.
20. The communications device of claim 16 , wherein the communications device is configured to transmit at least the scrambled LTE broadcast channel data within a broadcast channel in accordance with a long term evolution standard.