Ada-TokenCom: Rate-Adaptive Token Communications via Large-Model-Driven Token Compression and Generation
Authors: Zijun Zhang, Li Qiao, Mahdi Boloursaz Mashhadi, Zhen Gao, Mehdi Bennis, Kaibin Huang
Organizations: School of Information and Electronics, Beijing Institute of Technology (Zhuhai), Zhuhai 519088, China · Department of Electrical and Computer Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong SAR · University of Surrey, Guildford, U.K. · Centre for Wireless Communications, University of Oulu, 90014 Oulu, Finland
Token Communications (TokenCom) has recently emerged as a new paradigm in which tokens serve as unified units for communication and computation, enabling efficient multimodal semantic and goal-oriented transmission. In this paper, we develop Ada-TokenCom, a rate-adaptive TokenCom framework based on large autoregressive models, which integrates next-token prediction with arithmetic coding to achieve ultra-low bitrate semantic communication at the token level. We propose a mixed reconstruction/generation scheme, where the transmitter encodes and transmits the highly informative tokens at the beginning of the token sequence leveraging a pre-trained autoregressive large model, while the receiver uses an identical model to predict the rest. Moreover, we design a Lyapunov-based algorithm to dynamically optimize both the source compression rate and the modulation and coding scheme, adapting to time-varying network conditions. Simulation results demonstrate that our proposed Ada-TokenCom framework outperforms both digital and deep joint source-channel coding-based semantic communication baselines.
Figures & tables
Fig. 1: Block diagram of the proposed Ada-TokenCom framework.
Fig. 2: Self-information as a function of token position (a) with class label as conditional information ( cond ) and (b) with null label ( uncond ), averaged over 1000 images from ImageNet-V2 datatset, for pretrained AR models with different parameter scales.
Fig. 3: Visualization of self-information on a 16×16 VQGAN latent grid using LlamaGen-L. Fluctuations predominantly occur at positions associated with discontinuities, which are induced by flattening the 2D latent grid and mapping the grid into 1D token sequence.
Fig. 4: Visualization for (a) heatmap of conditional entropy on a 16×16 VQGAN latent grid, and (b) samples of their decoded image with specified lengths of head tokens.
Model
Params 1
Inference Cost 2
Avg. Bits (cond)
Avg. Bits (uncond)
LlamaGen-B
72 M + 111 M
52.56 G
11.42
11.54
LlamaGen-L
72 M + 343 M
173.57 G
11.22
11.33
Taming Transf.
76 M + 1411 M
364.00 G
8.09
8.37
TABLE I: Average conditional self-information per token under different AR models.
Fig. 5: Performance comparison between the proposed Ada-TokenCom framework and benchmark image compression methods on the ImageNet-V2 dataset.
Fig. 6: Visualization of image reconstruction at different token truncating levels for t2i and c2i scenarios.
QPSK
16QAM
Code
Rate
Polynominal
αm
βm
αm
βm
Uncoded
1
−
1.742
-2.188
8.662
-13.306
Conv Code
1/2
[5,7]8
0.320
0.011
1.103
-0.277
Conv Code
2/3
[51,31,13]8
0.157
0.225
0.506
0.623
Conv Code
1/5
[35, 33, 27, 37, 23] 8
0.086
0.070
0.268
0.075
Turbo Code
1/3
[1,5/7,5/7]8
0.031
0.560
0.087
1.630
TABLE II: Candidate Sets of Channel Coding and Modulations Schemes
n∗
256
224
192
160
128
96
64
32
A
0.937
0.931
0.922
0.913
0.898
0.880
0.861
0.843
TABLE III: Semantic quality A (CLIP) Under Different Prefix Lengths n∗
Fig. 7: Performance comparison of reconstruction among the proposed LlamaGen-based Ada-TokenCom framework, SwinJSCC with rate and SNR adaptation on the ImageNet-V2 dataset.
Fig. 8: Visualization of image reconstruction at different channel bandwidth ratios for the Ada-TokenCom framework and SwinJSCC with rate and SNR adaptation at SNR=12dB . The value shown on each image denotes CBR / CLIP score.
Fig. 9: Effect of the Lyapunov weight η on terminal budget utilization at (a) Cth=500 and (b) Cth=1500 under four SNR regimes.
Fig. 10: Per-slot cumulative CLIP and (1−LPIPS) (upper row) with their historical average link utilization (lower row) under SNR∼N(12,10) when Cth=500 .
Method
Parameters / M (Encoder + Decoder)
Inference Cost / GFlops (Encoder + Decoder)
Encoder Latency
Decoder Latency
SwinJSCC
18.34 + 14.73
35.01 + 34.11
10 ms
6 ms
HiFiC
24.69 + 168.28
15.28 + 116.47
83 ms
188 ms
BPG
–
–
307–824 ms
29–43 ms
Ada-TokenCom (LlamaGen-L) 2
372.21 + 385.36
311.41 + 422.47
19 ms
1012 ms
TABLE IV: Comparison of model size, inference cost, and computation latency 1 .
5GIC & 6GIC, Institute for Communication Systems (ICS), University of Surrey, U.K. · Smart Internet Lab, University of Bristol, U.K. · British Telecom Research Lab, BT Group plc, U.K.
School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China · 5GIC & 6GIC, Institute for Communication Systems (ICS), University of Surrey, Guildford, United Kingdom · Centre for Wireless Communications, University of Oulu, 90014 Oulu, Finland +1