Scrambling Sequences for Wireless Networks

Abstract

An integrated circuit includes logic configured to generate scrambling sequences, each based on a different scrambling seed, for a smart-utility-network data packet communication. A Hamming distance between any two scrambling sequences is half the length of a PSDU of the data packet or greater.

What is claimed is: 
     
         1 . An integrated circuit, comprising:
 logic configured to generate scrambling sequences, each based on a different scrambling seed, for a smart-utility-network data packet communication;   wherein when a retransmission is requested for a packet, a scrambling sequence different from the last scrambling sequence is used in the retransmission of the packet; and   wherein when retransmission is requested for a packet, a media access control (MAC) changes a scrambler seed by setting a scramble field to “00” when a physical layer (PHY) is initialized and thereafter increments the scrambler field using a 2-bit rollover counter.   
     
     
         2 . The integrated circuit of  claim 1  wherein the length of a protocol service data unit (PSDU) is 80 bits or less. 
     
     
         3 . The integrated circuit of  claim 1  wherein the logic comprises a PN 9  scrambler. 
     
     
         4 . The integrated circuit of  claim 3  wherein the scrambling seed is selected from the group consisting of: 000010111, 000011100, 101110111, and 101111100. 
     
     
         5 . The integrated circuit of  claim 1  wherein the logic comprises a PN 7  scrambler. 
     
     
         6 . The integrated circuit of  claim 1  wherein the logic is implemented in an orthogonal frequency division multiplexing (OFDM) physical layer. 
     
     
         7 . An apparatus, comprising:
 a transceiver with a physical layer for smart-utility-network data packet communication; and   a processor coupled to the transceiver and configured to generate scrambling sequences, each based on a scrambling seed, for a data packet transmitted by the transceiver;   wherein when a retransmission is requested for a packet, a scrambling sequence different from the last scrambling sequence is used in the retransmission of the packet; and   wherein when retransmission is requested for a packet, a media access control (MAC) changes a scrambler seed by setting a scramble field to “00” when a physical layer (PHY) is initialized and thereafter increments the scrambler field using a 2-bit rollover counter.   
     
     
         8 . The apparatus of  claim 7  wherein the length of the PSDU is 80 bits or less. 
     
     
         9 . The apparatus of  claim 7  wherein the processor generates the scrambling sequences using a PN 9  scrambler. 
     
     
         10 . The apparatus of  claim 9  wherein the scrambling seed is selected from the group consisting of: 000010111, 000011100, 101110111, and 101111100. 
     
     
         11 . The apparatus of  claim 7  wherein the processor generates the scrambling sequences using a PN 7  scrambler.