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 a first scrambling sequence is selected when the number of transmit antennas is less than 4 and a second scrambling sequence is selected when the number of transmit antennas is 4; and
scrambling, by the communications device, a plurality of bits of data using the selected scrambling sequence.
2. The method of claim 1 , wherein the 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 to a remote communication device.
4. The method of claim 1 , further comprising transmitting, by the communications device, the plurality of scrambled bits within a broadcast channel.
5. The method of claim 3 , wherein the plurality of scrambled bits are transmitted using a plurality of resource elements.
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 a first scrambling sequence is selected when the number of transmit antennas is less than 4 and a second scrambling sequence is selected when the number of transmit antennas is 4; and
scramble a plurality of bits of data using the selected scrambling sequence.
7. The communications device of claim 6 , wherein the 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.
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.
10. The communications device of claim 8 , wherein the plurality of scrambled bits are transmitted using a plurality of resource elements.
11. 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 a scrambling sequence of (0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1) is selected when the number of transmit antennas is 4; and
scrambling, by the communications device, a plurality of bits of data using the selected scrambling sequence.
12. The method of claim 11 , wherein the data comprises transport data and cyclic redundancy check (CRC) data, wherein the CRC data is computed based on the transport data.
13. The method of claim 11 , further comprising transmitting, by the communications device, the plurality of scrambled bits to a remote communication device.
14. The method of claim 11 , further comprising transmitting, by the communications device, the plurality of scrambled bits within a broadcast channel.
15. The method of claim 13 , wherein the plurality of scrambled bits are transmitted using a plurality of resource elements.
16. 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 a scrambling sequence of (0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1) is selected when the number of transmit antennas is 4; and
scramble a plurality of bits of data using the selected scrambling sequence.
17. The communications device of claim 16 , wherein the data comprises transport data and cyclic redundancy check (CRC) data, wherein the CRC data is computed based on the transport data.
18. The communications device of claim 16 , wherein the communications device is configured to transmit the plurality of scrambled bits to a remote communication device.
19. The communications device of claim 16 , wherein the communications device transmits, to a remote communication device, the plurality of scrambled bits within a broadcast channel.
20. The communications device of claim 18 , wherein the plurality of scrambled bits are transmitted using a plurality of resource elements.