Pilot use in orthogonal frequency division multiplexing based spread spectrum multiple access systems

Apparatus for use in a base station in an orthogonal frequency division multiplexing (OFDM) based spread spectrum multiple access wireless system comprising:

• a sequence generator for generating one or more pilot tone hopping sequences each including pilot tones, said pilot tones each being generated at frequency and time instants in a time-frequency grid;
• a waveform generator, responsive to said one or more pilot tone hopping sequences, for generating a waveform for transmission;
• and
• wherein said waveform generator generates a waveform in accordance with
• ∑
• i
• =
• 1
• N
• pil
• ⁢
• ⁢
• C
• k
• S
• i
• ⁢
• ⅇ
• 2
• ⁢
• π
• ⁢
• ⁢
• f
• k
• S
• i
• ⁢
• Δ
• ⁢
• ⁢
• fi
• ,
• where fkSi are given by the sequence Si={fisi, fiSi, . . . } for i=1, . . . Npil. Δf is the basic frequency spacing between adjacent tones, CkSi is a known symbol to be transmitted at the kth symbol instant and tone fkSi.

Apparatus for use in a base station in an orthogonal frequency division multiplexing (OFDM) based spread spectrum multiple access wireless system comprising:

• a sequence generator for generating one or more pilot tone hopping sequences each including pilot tones, said pilot tones each being generated at frequency and time instants in a time-frequency grid;
• and
• a waveform generator, responsive to said one or more pilot tone hopping sequences, for generating a waveform for transmission,
• wherein said waveform generator generates a waveform in accordance with
• ∑
• i
• =
• 1
• N
• pil
• ⁢
• ⁢
• C
• k
• S
• i
• ⁢
• Γ
• k
• S
• i
• ⁢
• ⅇ
• 2
• ⁢
• π
• ⁢
• ⁢
• f
• k
• S
• i
• ⁢
• Δ
• ⁢
• ⁢
• fi
• ,
• where fkSi are given by the sequence Si={fisi, fiSi, . . . } for i=1, . . . Npil, Δf is the basic frequency spacing between adjacent tones, CkSi, is a known symbol to be transmitted at the kth symbol instant and tone fkSi, and εkSi, if fkSiε[0, N, −1], and ΓkSi=0, otherwise.

A method for use in a base station in an orthogonal frequency division multiplexing (OFDM) based spread spectrum multiple access wireless system comprising the steps of:

• generating one or more pilot tone hopping sequences each including pilot tones, said pilot tones each being generated at frequency and time instants in a time-frequency grid;
• in response to said one or more pilot tone hopping sequences, generating a waveform for transmission;
• and
• wherein said step of generating one or more pilot tone hopping sequences includes a step of generating each of said one or more pilot tone hopping sequences in accordance with Si={fisi, fiSi, . . . } for i=1, . . . Npil, and
• wherein fkSi=Z{(a(k mod T)+si)mod p+d}, where “k” is a time instant index, “T”, “a”, “si” and “d” are integer constants, “p” is a prime constant, and “Z” is a permutation operator.

A method for use in a base station in an orthogonal frequency division multiplexing (OFDM) based spread spectrum multiple access wireless system comprising the steps of:

• generating one or more pilot tone hopping sequences each including pilot tones, said pilot tones each being generated at frequency and time instants in a time-frequency grid;
• in response to said one or more pilot tone hopping sequences, generating a waveform for transmission, and wherein said step of generating said waveform includes a step of generating said waveform in accordance with
• ∑
• i
• =
• 1
• N
• pil
• ⁢
• ⁢
• C
• k
• S
• i
• ⁢
• ⅇ
• 2
• ⁢
• π
• ⁢
• ⁢
• f
• k
• S
• i
• ⁢
• Δ
• ⁢
• ⁢
• fi
• ,
• where fkSi are given by the sequence Si={fisi, fiSi, . . . } for i=1, . . . Npil, where Δf is the basic frequency spacing between adjacent tones, CkSi is a known symbol to be transmitted at the kth symbol instant and tone fkSi.

A method for use in a base station in an orthogonal frequency division multiplexing (OFDM) based spread spectrum multiple access wireless system comprising the steps of:

• generating one or more pilot tone hopping sequences each including pilot tones, said pilot tones each being generated at frequency and time instants in a time-frequency grid;
• in response to said one or more pilot tone hopping sequences, generating a waveform for transmission;
• and
• wherein said step of generating said waveform includes a step of generating-said waveform in accordance with
• ∑
• i
• =
• 1
• N
• pil
• ⁢
• ⁢
• C
• k
• S
• i
• ⁢
• Γ
• k
• S
• i
• ⁢
• ⅇ
• 2
• ⁢
• π
• ⁢
• ⁢
• f
• k
• S
• i
• ⁢
• Δ
• ⁢
• ⁢
• fi
• ,
• where fkSi are given by the sequence Si={fisi, fiSi, . . . } for i=1, . . . Npil, where Δf is the basic frequency spacing between adjacent tones, CkSi is a known symbol to be transmitted at the kth symbol instant and tone fkSi and ΓkSi=1, if fkSiε[0, Nt−1], and ΓkSi=0, otherwise.

Apparatus for use in a base station in an orthogonal frequency division multiplexing (OFDM) based spread spectrum multiple access wireless system comprising:

• means for generating one or more pilot tone hopping sequences each including pilot tones, said pilot tones each being generated at frequency and time instants in a time-frequency grid;
• and
• means, responsive to said one or more pilot tone hopping sequences, for generating a waveform for transmission, wherein said step of generating one or more pilot tone hopping sequences includes a step of generating each of said one or more pilot tone hopping sequences in accordance with Si={fisi, fiSi, . . . } for i=1, . . . Npil, and
• wherein fkSi=Z{(a(k mod T)+si)mod p+d}, where “k” is a time instant index, “T”, “a”, “si” and “d” are integer constants, “p” is a prime constant, and “Z” is a permutation operator.

Apparatus for use in a base station in an orthogonal frequency division multiplexing (OFDM) based spread spectrum multiple access wireless system comprising:

• means for generating one or more pilot tone hopping sequences each including pilot tones, said pilot tones each being generated at frequency and time instants in a time-frequency grid;
• means, responsive to said one or more pilot tone hopping sequences, for generating a waveform for transmission;
• and
• wherein said means for generating said waveform includes means for generating said waveform in accordance with
• ∑
• i
• =
• 1
• N
• pil
• ⁢
• ⁢
• C
• k
• ′S
• i
• ⁢
• ⅇ
• 2
• ⁢
• π
• ⁢
• ⁢
• f
• k
• S
• i
• ⁢
• Δ
• ⁢
• ⁢
• fi
• ,
• where fkSi are given by the sequence Si={fisi, fiSi, . . . } for i=1, . . . Npil, where Δf is the basic frequency spacing between adjacent tones, CkSi is a known symbol to be transmitted at the kth symbol instant and tone fkSi.

Apparatus for use in a base station in an orthogonal frequency division multiplexing (OFDM) based spread spectrum multiple access wireless system comprising:

• means for generating one or more pilot tone hopping sequences each including pilot tones, said pilot tones each being generated at frequency and time instants in a time-frequency grid;
• means, responsive to said one or more pilot tone hopping sequences, for generating a waveform for transmission;
• and
• wherein said means for generating said waveform includes means for generating said waveform in accordance with
• ∑
• i
• =
• 1
• N
• pil
• ⁢
• ⁢
• C
• k
• S
• i
• ⁢
• Γ
• k
• S
• i
• ⁢
• ⅇ
• 2
• ⁢
• π
• ⁢
• ⁢
• f
• k
• S
• i
• ⁢
• Δ
• ⁢
• ⁢
• fi
• ,
• where fkSi are given by the sequence Si={fisi, fiSi, . . . } for i=1, . . . Npil, where Δf is the basic frequency spacing between adjacent tones, CkSi is a known symbol to be transmitted at the kth symbol instant and tone fkSi and ΓkSi=1, if fkSiε[0, Nt−1], and ΓkSi=0, otherwise.